%bochsdefs; ]> KevinLawton BryceDenney N. DavidGuarneri VolkerRuppert ChristopheBothamy MichaelCalabrese StanislavShwartsman

Bochs is a program that simulates a complete Intel x86 computer. It can be configured to act like a 386, 486, Pentium, Pentium II, Pentium III, Pentium 4 or even like x86-64 CPU, including optional MMX, SSEx and 3DNow! instructions. Bochs interprets every instruction from power-up to reboot, and has device models for all of the standard PC peripherals: keyboard, mouse, VGA card/monitor, disks, timer chips, network card, etc. Because Bochs simulates the whole PC environment, the software running in the simulation "believes" it is running on a real machine. This approach allows Bochs to run a wide variety of software with no modification, include most popular x86 operating systems: Windows 95/98/NT/2000/XP and Vista, all Linux flavors, all BSD flavors, and more. Bochs is written in the C++ programming language, and is designed to run on many different host platforms Since Bochs can run on one kind of machine and simulate another machine, we have to be clear in our terminology to avoid confusion. The host platform is the machine that runs the Bochs software. The guest platform is the operating system and applications that Bochs is simulating. , including x86, PPC, Alpha, Sun, and MIPS. No matter what the host platform is, Bochs still simulates x86 hardware. In other words, it does not depend on the native instructions of the host machine at all. This is both a strength and a weakness, and it's the major difference between Bochs and many other x86 emulation software such as plex86, VMware, etc. Because Bochs uses software simulation for every single x86 instruction, it can simulate a Windows application on an Alpha or Sun workstation. However, the downside of Bochs' approach is simulation performance. To model the processor accurately, Bochs must run many instructions for every simulated x86 instruction, and this makes the simulated machine many times slower than the physical machine. Commercial PC emulators (VMware, Connectix, etc.) can achieve much high emulation speed using a technique called virtualization Virtualization takes advantage of simulating x86 instructions on an x86 machine, allowing large portions of the simulation to take place at native hardware speed. Whenever the simulated machine talks to the hardware or enters certain privileged modes (such as in kernel code), the simulator typically takes control and simulates that code in software at much slower speed, just like Bochs does. , but they are neither portable to non-x86 platforms nor open source. The Plex86 project is working toward an open-source x86 simulator with virtualization. To do anything interesting in the simulated machine, Bochs needs to interact with the operating system on the host platform (the host OS). When you press a key in the Bochs display window, a key event goes into the device model for the keyboard. When the simulated machine needs to read from the simulated hard disk, Bochs reads from a disk image file on the host machine. When the simulated machine sends a network packet to the local network, Bochs uses the host platform's network card to send the packet out into the real world. These interactions between Bochs and the host operating system can be complicated, and in some cases they are host platform specific. Sending a network packet in FreeBSD requires different code than sending the packet in Windows XP, for example. For this reason, certain features are supported on some host platforms and not others. On GNU/Linux, Bochs can simulate a network card that communicates with the world, but on BeOS the simulated network card may not work because the communication code between the device model and the BeOS operating system has not been written. Bochs was written by Kevin Lawton starting in 1994. It began as a commercial product, which you could buy with source code for ... &NEEDHELP; We need a Bochs historian to help out here. For background, it would be interesting to know how much Bochs used to cost and what it was used for. I thought I saw an interview out there somewhere where Kevin says why he started it and some more background information. Finally, in March 2000, MandrakeSoft (now called Mandriva) bought Bochs and made it open source under the GNU LGPL. In March 2001, Kevin helped a few developers to move all Bochs activities from bochs.com to a new site at bochs.sourceforge.net. Since then the Bochs project has settled into its new home, and around release times has even hit #1 most active project of the week at SourceForge.

It is hard to estimate how many people have tried Bochs or use it on a regular basis, but a few statistics give an indication. The bochs-developers mailing list, which is the primary source of news on bugs and releases, has over 400 subscribers. The latest version has been downloaded over 150,000 times from SourceForge, not counting any mirror website or CVS users. Bochs has many possible uses, and different people use it for different things. Many people use it to run applications in a second operating system without needing two different computers or dual-booting. Running Windows software on a non-x86 workstation or on an x86 Unix box are common uses. Also, because every hardware instruction and every line of simulator code is accessible, Bochs is used extensively for debugging new operating systems. If you were writing boot code for your home-brewed x86 operating system and it didn't work right, booting it in Bochs could give you great visibility into what is really going on. The Bochs debugger lets you simulate quickly or slowly, pausing whenever you want to look at the contents of memory or the CPU registers. Or, if you wanted to study which parts of a program take the most time, you could use Bochs to measure how often certain pieces of the code were executed. Bochs has been used as a teaching tool in Operating Systems classes, in which students used and modified it to learn how the PC hardware works. As a final project the students had to add a new peripheral device, so they had to learn all about I/O ports, interrupts, and device drivers. In industry, it is used to support legacy applications on modern hardware, and as a reference model when testing new x86-compatible hardware. There may be as many uses of Bochs as there are users. Do you want to run your old DOS games? Or learn how to program under GNU/Linux, without leaving your Windows desktop? Or reverse engineer your printer driver? You decide.

Bochs is very useful for some applications, and not well suited to others. This section tries to answer the question, "Is Bochs right for me?" Bochs may or may not be right for you, depending on what it is you want to do. Perhaps all you want to do is run one or two applications native to Microsoft Windows on GNU/Linux, or vice-versa. Perhaps your biggest concern is speed and performance. Maybe you don't mind tweaking a few files here and there when you want another application to work in that setting. In cases where the objective is to simulate x86 hardware on an x86, Plex86, Wine, and VMware might be your best options. On the other hand, perhaps you have a vital application running on an older operating system that only runs well on old hardware. You are concerned that the life cycle of this hardware is coming to an end, and your backup and restoration hardware and tools no longer suffice for the amount of data that you have. You need to transfer backup disk images over a network, and want to use modern procedures for hardware maintenance. Perhaps the application is important enough to run on a larger computer, such as a 64-bit machine, or even a mainframe. Bochs would be an excellent option in such a scenario. Perhaps your objective is to debug software or hardware drivers. Bochs offers a controlled environment that can better assist you in determining cause and effect relationships. You can take snapshots that show you what is going on behind the scenes. You can isolate the line that caused that crash. You can have multiple images and compare them under a microscope. In these situation, Bochs could save you time and resources. Information Technology changes faster than any other field. It is very easy to forget transitional software that came and went. But history is important to all fields, and to build on the future, it is important to understand the past. Computer programmers, however, do not have the same advantage as an architect, who can, for example, take a trip to Greece and touch a pillar. Much of the history of Computer Science is left on corroding floppies and malfunctioning hardware. Bochs gives you the benefit of having one or more complete environments where you can understand firsthand the behavior of operating systems and programs. This cannot be achieved with an "emulator" such as Wine.

Whether Bochs works for you depends on your host hardware, host operating system, guest operating system, guest software, and your ability to work in a command-line environment using documentation. There is no wizard to help you through the setup process. You do not get a recovery or installation disk to assist you in the process of installing a guest operating system. Bochs only provides you with the "virtual hardware", and it is up to you to do the rest. Bochs will run on Windows, GNU/Linux, FreeBSD, OpenBSD, or BeOS. If you are running on x86 hardware, you have a range of choices. Check the installation section for your host platform to see what options Bochs supports on your platform. If the most important factor is speed, you may want to try a virtualization product instead of Bochs (VMware, VirtualBox, plex86). If you are using a non-x86 machine, then Bochs is one of the few choices for running x86 software. Bochs has been known to work on Solaris (Sparc), GNU/Linux (PowerPC/Alpha), MacOS (PowerPC), IRIX (MIPS), BeOS (PowerPC), Digital Unix (Alpha), and AIX (PowerPC). You can also find more detailed testing information on the testing status page on the &bochswebsite;.

Bochs is copyrighted by MandrakeSoft S.A. Mandriva has a web site at http://mandriva.com and distributed under the GNU Lesser General Public License Complete text of the GNU LGPL is included with the source code in a file called COPYING, and is also here. . The following text appears at the top of every source code file in the Bochs distribution: This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Before you install or use any Operating System, BIOS, or other software package within the Bochs PC emulation environment, make sure you are and will be in compliance with all the software licenses pertaining to the software you wish to install. It is completely your responsibility to provide licenses and records on all software that you install and/or use. It is also completely your responsibility to maintain total compliance with all Software Licenses involved. In the process of installing Software within the Bochs PC emulation environment, it may be helpful or necessary to copy or convert files from the original distribution format to a second format to facilitate the installation. You should delete the intermediate files after installation, making certain that only the original distribution files remain.

The following table shows the features of Bochs and which platforms they currently work with. Feature Supported? Description configure script Yes Bochs uses GNU autoconf to configure Makefiles and headers. Autoconf helps Bochs to compile on a wide variety of platforms. 386,486,Pentium Emulation Yes Bochs can be configured to emulate one of several families of Intel hardware. Some Pentium features are incomplete, such as SMM (System Management Mode). P6 and later CPU Emulation Yes Bochs can be configured to emulate any P6 family processor including optional MMX and SSE instructions. Pentium 4 Emulation Incomplete A few Pentium 4 features are incomplete, such as an on-chip APIC extensions (XAPIC) for SMP simulation. x86-64 Extensions Emulation Yes Bochs can be configured to emulate x86-64 with many recent Intel or AMD extensions. Command Line Debugger Yes Powerful command line debugger (optional) that lets you stop execution and examine registers and memory, set breakpoints, etc. GUI Debugger Yes Chourdakis Michael and Bruce Ewing contributed very powerful GUI frontend for Bochs internal debugger. GUI debugger frontend is supported for Win32 and GTK hosts. Floating Point Yes Uses software floating point engine based on SoftFloat floating point emulation library. Enhanced BIOS Yes Implements ElTorito, EDD v3.0, basic APM feature, PCIBIOS features and the PCI interrupt routing table. The latest version of the Bochs BIOS has a 32-bit init for ACPI, SMM and SMP. VGA Yes VGA color graphics emulation in a window. VBE (VESA) Support Yes Currently resolutions up to 2560x1600x32bpp are supported. You must enable VBE with the VGA extension option and use the LGPL'd VGABIOS. For more information see . Cirrus Logic video card Yes Cirrus Logic CL-GD5430 ISA or CL-GD5446 PCI video card support. For more information see . Floppy disk Yes Supports floppy disk images on all platforms: 2.88M 3.5", 1.44M 3.5", 1.2M 5.25", 720K 3.5" and 360K 5.25". On Unix and Windows 9x/NT/2000/XP, Bochs can access the physical floppy drive. It is also possible to use a local directory as VFAT media (1.44M only). Multiple ATA channels Yes Emulates up to 4 ATA channels. Up to 8 ATA/ATAPI emulated devices can be attached, two per ATA channel. So you can have eight hard disks or seven hard disks and a CD-ROM or four hard disks and four CD-ROMs, or one hard disk and seven CD-ROMs, etc... Hard disk Yes Emulates ATA-6/IDE hard drives via image files. Physical hard disk access is supported on some architecture, but NOT recommended, primarily for safety reasons. Hard disks up to 127GB are supported, on any platform that support large files access. It is also possible to use a local directory as VFAT drive. CD-ROM Yes Emulates ATAPI-4/IDE CD-ROM. The CD-ROMs can read from an ISO disk image on any platform. On Windows (9x/ME/NT/2000/XP), Linux, SunOS, FreeBSD, NetBSD, OpenBSD, Amiga/MorphOS, MacOSX and BeOS, Bochs can read from the physical CD-ROM drive. Starting with version 1.4, Bochs is even able to boot from a bootable CD or bootable ISO image. Keyboard Yes Emulates a PS/2 keyboard with North American key mappings. Optional keyboard layout remapping files are provided to support localized keyboard in X11 (Belgian, Danish, French, German, Italian, Russian, Slovenian, Spanish, Swedish, U.K.). Mouse Yes Emulates a serial, PS/2 or USB mouse with 3 buttons + optional mouse wheel support. Sound Blaster Yes Emulates a Sound Blaster 16 card (ISA, no plug&play). On Windows, Linux, FreeBSD, MacOS 9 and MacOSX, the output can be sent to the host computer's sound system, see for details. Network card Yes Emulates an NE2000 compatible network card. On Windows NT/2000, Linux, FreeBSD, and NetBSD, Bochs will forward packets to and from the operating system so that the guest OS can talk on the physical network. Unfortunately, on some platforms the guest OS can talk to any machine on the network BUT NOT the host machine. On Windows and on systems that allow the TAP or TUN/TAP interface, there is no such limitation. Often the host machine may be configured so the guest OS has access to the internet. On MacOSX, you may download the TUN driver from: Parallel Port Yes Parallel port emulation was added by Volker Ruppert for Bochs 1.3. Data that is sent to the parallel port by the guest OS can be saved into a file or sent directly into the parallel port device (Unix only). Serial Port Yes The serial port (16550A UART emulation) is usable, on GNU/Linux, NetBSD, OpenBSD, FreeBSD and MacOSX as host and guest. On other OSes the emulation is present, but the connection to hard- or software of the host is not implemented yet. Up to 4 ports are available. Gameport Yes Emulates a standard PC gameport. The connection to a real joystick is currently supported on Linux and win32 only. PCI Yes Emulates most of the i440FX PCI chipset. The Host-to-PCI bridge (PMC/DBX), the PCI-to-ISA bridge and the PCI IDE controller (PIIX3) are available. For PCI cards there are 5 PCI slots supported. USB incomplete Two types of host controllers (UHCI and OHCI) and the devices 'mouse', 'tablet', 'keypad', 'disk', 'cdrom', 'hub' and 'printer'. are available. Plugging in and removing devices at runtime is possible. Access to real hardware is not implemented yet. Plugins Yes Compiling gui and devices as plugins is supported on Linux, MacOS X, Solaris, Cygwin and MinGW/MSYS. PIC Yes Master and slave programmable interrupt controller. CMOS functions Yes Real time clock (RTC) and CMOS RAM are available Dynamic Translation/Virtualization No Because Bochs is designed to be portable, it does not attempt to do any dynamic code translation or virtualization. See for details. Simulate a Multiprocessor Yes Bochs can be configured to simulate up to 8 processors. This feature is still experimental, but it can boot several Linux or Windows guests with SMP support. Please note that this does NOT mean that Bochs can run faster on a physical SMP machine. Take advantage of your SMP box No At present, Bochs does not use threads or parallel processing, so it will not run any faster on multiprocessor hardware. Copy and Paste Yes Depending on the host platform, the text-mode screen text can be exported to the clipboard. Text in the clipboard can also be pasted, through Bochs, to the guest OS, as simulated keystrokes.

The following table shows the supported platforms with a small description and the available display libraries on these platforms. The display library is the code that displays the Bochs VGA screen and handles keyboard and mouse events. Platform Description Display Libraries Unix/X11 X windows has always been well supported because it was Kevin Lawton's main development platform. Bryce Denney maintains the Unix/X11 platform now. Most features and fixes (not all) are tried first in Unix and then ported to the others; see for compile instructions. x, sdl, wx, term, rfb Win32 This port was done by David Ross and is now maintained by Don Becker. You can compile with Microsoft Visual C++, see for compile instructions, or Cygwin, see . win32, sdl, wx, rfb BeOS Kevin Lawton wrote this port, originally to R3/PPC using CodeWarrior. It now works on R4/x86 with egcs. Simon Huet picked up maintaining/reworking the BeOS GUI port. In September 2001, Bernd Korz of Yellow Tab, Inc. (www.yellowtab.com), took over the BeOS/Zeta port, and is working on raw CD-ROM and raw floppy support. For compiling, see . beos, sdl MacOS X Emmanuel Mailliard ported the Macintosh code to MacOS X with Carbon API. Jeremy Parsons (Br'fin) has been maintaining the MacOS X port since March 2002; see for compile instructions. carbon, x, rfb, sdl PowerPC-Macintosh David Batterham ported Bochs to the Mac. He compiled with CodeWarrior Pro R1 (CW12) but has not had time to maintain the Mac port since early 2000. If you have Mac development tools and want to contribute, contact the &devlist;; see for compile instructions. macos Amiga/MorphOS This port is written and maintained by Nicholai Benalal, see for compile instructions. amigaos OS/2 Nick Behnken used PE2LX to translate David Ross' Win32 port to an OS/2 program. This hasn't been updated for a long time, and Nick Behnken's page seems to be inactive. Also, Craig Ballantyne ported Bochs to OS/2, but his web page has disappeared and his port has not been updated since March 2000. If you want to bring the OS/2 port up to date, contact the &devlist;. ???

Is Bochs Open Source? Yes! Bochs is released under the GNU LGPL, much thanks to MandrakeSoft (now called Mandriva). How do you pronounce "Bochs"? Phonetically the same as the English word "box". It's just a play on the word "box", since techies like to call their machines a "Linux box", "Windows box", ... Bochs emulates a box inside a box. Who is the author of Bochs? Kevin Lawton is the primary author of Bochs. There have been bug fixes, enhancements, and code contributions from some few hundred people, so it is not possible to list them all. Recently, Kevin has been working on a PC virtualization project called plex86. In Fall 2002, he made contributed some major CPU speedups and helped with integration and debugging of the x86-64 emulation code. Who maintains Bochs now? With Kevin's help, in April 2001, the members of the bochs-developers mailing list set up a new official Bochs site hosted by Source Forge. The admins on this project are Greg Alexander, Don Becker, Christophe Bothamy, Bryce Denney, Volker Ruppert and Stanislav Shwartsman. Tell me about performance when running Bochs. Because Bochs emulates every x86 instruction and all the devices in a PC system, it does not reach high emulation speeds. Users who have an x86 processor and want the highest emulation speeds may want to consider PC virtualization software such as plex86 or VirtualBox (free software). Another related project is QEMU. Does Bochs use a disk partition to install the OS? No. It uses a disk image file, which is simply a large file, like any other file, on your platform's disk. Why can't I use Bochs with my current WinXP installation? Think about this. If you had two different PC's, they would require different hardware drivers. So you may not be able to safely move a disk drive with WinXP on it, from one to the other. Bochs is no different. It emulates a certain set of hardware devices, and requires each OS be configured for those devices. Is there a developer's email list for Bochs? Yes. For instructions on joining, refer to . Is there an IRC channel for Bochs? Yes. You will usually find Bochs developers and users on IRC at irc.freenode.net:6667, channel #bochs. Do you know of any snapshots of Bochs running Windows? Yes! Look for "Screen Shots" on &bochs-sf-net; or on other Bochs sites. Does Bochs support a CD-ROM? Yes, a CD-ROM is supported in Linux, Windows, BeOS, and most BSDs. The CD-ROM drivers for Bochs allow the guest operating system to access the host operating system's CD-ROM data directly. Does Bochs support a sound device? Yes, there is Sound Blaster emulation support for most common operation systems, see for details. Does Bochs support a network card? Yes. Bochs contains a model of an NE2000 compatible network card. Networking is not supported on all platforms. See for details. What applications are known to run inside of Bochs? Well, lot's of different OS's run inside of Bochs, so thousands. I'm assuming you are asking about Windows programs. To give you a few, the following ones from the Winstone'98 tests worked: Access 97, CorelDRAW! 7, Excel 97, Lotus 1-2-3 97, Word 97, PowerPoint 97, Quattro Pro 7, WordPerfect 7. Also, I've compiled an entire OS kernel inside Bochs before. Not to mention, running DOOM, though at then-pathetic speeds. I am new to Bochs, how do I start? You should read first. Next, you can check if there specific instructions on how to install your (guest) OS inside of Bochs.

The change log is stored in the Bochs source code in a file called CHANGES. Click here to see the latest version of the CHANGES file. The link above is provided by Source Forge and might change one day. If it stops working, you can download the current source code with CVS and read the CHANGES file there.

You can download Bochs from our web site at &bochs-sf-net;. First, you need to choose what version to get: a recent release or a development version. If you trying to get things working for the first time, a release version is recommended since it has been tested the most. The development versions (sometimes called snapshots) may have some newer bug fixes and new features, but have not been tested as much as the releases. Second, you can choose to compile Bochs from source code or install a binary (if one is available for your platform). Binary packages will be quicker to install, and most include a small demo of a guest operating system called DLX Linux to get you started. However, some features can only be enabled if you compile Bochs yourself, for example the Bochs debugger. For multiuser systems, you will probably need system administrator privileges (root) to install a binary package. If you decide to get a binary, download it to your hard disk, uncompress it, then go to the section called Installing a Binary for more information. If you are going to compile Bochs yourself, you need the gzipped tarball containing the source code, called bochs-version.tar.gz. For Windows and Mac, the prebuilt Makefiles are separate, so also get the Makefiles for your platform. To unpack a compressed TAR file A TAR file is a single file that contains many files packed inside. Bochs TAR files are compressed with a program called gzip, and another program called gunzip is used to uncompress them. on a Unix machine On Windows, look for software called WinZip to unpack the TAR. , type gunzip -c bochs-version.tar.gz | tar -xvf - This creates a directory called bochs-version full of files. This directory will be referred to as &bochsdir;. Go into &bochsdir; and you are ready to compile. Instructions for compiling Bochs are in the section, Compiling Bochs. Alternatively, you can also obtain the sources for any Bochs version using CVS. See the CVS instructions for details.

CVS, or Concurrent Version System, is a software development tool that helps to keep track of the different revisions of each file. It is used by many open source (and commercial) projects to allow multiple developers to share their changes to the source code. The Bochs source code and documentation are available using CVS You can download CVS software and documentation from www.cvshome.org. .

When you have CVS installed, the first step is to do a login and checkout. The initial checkout command is long and ugly, but usually you only have to do it once. The example below shows the CVS checkout process in Unix. On the Windows platform, you can download a CVS client from cvshome.com, or use CVS within Cygwin Cygwin is an open source Unix-like environment for Windows platforms, available at www.cygwin.com. .

user$ cvs -d:pserver:anonymous@bochs.cvs.sourceforge.net:/cvsroot/bochs login (Logging in to anonymous@bochs.cvs.sourceforge.net) CVS password: (there is no password, just press Enter) user$ cvs -z3 -d:pserver:anonymous@bochs.cvs.sourceforge.net:/cvsroot/bochs checkout bochs cvs server: Updating bochs U bochs/.bochsrc U bochs/.conf.beos-x86-R4 U bochs/.conf.macos . . (This might take a few minutes, depending on your network connection.) . U bochs/patches/patch.seg-limit-real user$ cd bochs user$ ls Bochs.proj.hqx bxversion.h fpu/ osdep.cc CHANGES config.h.in gui/ osdep.h COPYING configure* install-x11-fonts* patches/ CVS/ configure.in instrument/ pc_system.cc Makefile.in cpu/ iodev/ pc_system.h README bx_debug/ load32bitOShack.cc state_file.cc TESTFORM.txt disasm/ logio.cc state_file.h bios/ doc/ macintosh.txt win32.txt bochs.h docs-html/ main.cc bochs.rsrc.hqx dynamic/ memory/ build/ font/ misc/ user$ _

This is just an example output of a checkout of an older version of Bochs. You most likely will see more/other files. If you have write access to the Bochs CVS tree, the checkout command is different for you. See the Developers Guide See the Developers Guide and/or look at CVS repository information, section "Developer CVS Access via SSH", for instructions. for details. If you use remote CVS for other projects, you might have already set the environment variable CVS_RSH in your configuration files. For the CVS checkout to work as shown above, the CVS_RSH variable should either be empty or set to rsh. The CVS checkout process (above) gives you a directory called bochs that contains the very latest source code. I will refer to this directory as &bochsdir;. In each subdirectory directory there's also a directory called "CVS" which tells the cvs software where the code was checked out, what version you have, and where to go for future updates.

Most developers use CVS to always give them the latest source code. The minute that any developer checks in a change, they are available to everyone else through CVS. You just have to type cvs update -d -A in the &bochsdir; directory, and CVS will retrieve any files and directories that have been changed since you did a checkout. If you update regularly, each update takes a short time because it downloads only the files that changed. The -d option tells cvs to download new directories that have been checked in, not just files. The -A option means to get the most recent version of each file, as opposed to a release version. See Getting a release version Both -d and -A can be omitted in many cases, once you are familiar with the process. The cvs update -A -d command tells you if any new files have been downloaded from the server, and it also tells you if you have modified any of the CVS-controlled files. As it checks through the source directories, it will list files that have changed, with a single letter before the name that tells the status of that file. The most common status letters are listed below. Letter Meaning Description ? unknown This file is in your bochs directory, but CVS does not know anything about it. For example, when you compile Bochs, any files created during the build process appear as ?. U update cvs downloaded a new version of this file because it changed on the server, usually because someone else did a checkin. P patch This does the same as U, but instead of sending the whole file (update), only a diff/patch is sent, thus, less bandwidth is used. M modified You have changed this file on your disk, so it no longer matches the version on the server. This is not a problem; it's just for your information. If you want, you can discard your changes and get a fresh copy by deleting the file and running cvs update again. C conflict You have changed this file on your disk, but this change conflicts with a change that was checked in. Conflicts occur when two people change the same line of code in different ways. You need to edit the conflicting file(s) and clean it up by hand. Or, sometimes it's easiest to discard your own edits and download a fresh copy, by deleting the conflicting file and running cvs update again. If you have been using cvs update with "sticky tags" to retrieve other versions, as described later, cvs will remember which version you were looking at. In this case, a cvs update will keep your sources consistent with that version. If you want to get back to looking at the latest code again, be sure to use the -A option to clears the sticky tags.

Once you have a CVS checkout, you can also use the update command to get the Bochs source code for any release since March 2000. The command is cvs update -d -r tagname. The tag tells which release you want, and it can be one of the following: Bochs version Release tag for CVS 2.4.1 REL_2_4_1_FINAL 2.4 REL_2_4_FINAL 2.3.7 REL_2_3_7_FINAL 2.3.6 REL_2_3_6_FINAL 2.3.5 REL_2_3_5_FINAL 2.3 REL_2_3_FINAL 2.2.6 (intermediate2) REL_2_2_6_FINAL 2.2.5 (intermediate1) REL_2_2_5_FINAL 2.2.1 (bugfix1) REL_2_2_1_FINAL 2.2 REL_2_2_FINAL 2.1.1 (bugfix1) REL_2_1_1_FINAL 2.1 REL_2_1_FINAL 2.0.2 (bugfix2) REL_2_0_2_FINAL 2.0.1 (bugfix1) REL_2_0_1_FINAL 2.0 REL_2_0_FINAL 1.4.1 (bugfix1) REL_1_4_1_FINAL 1.4 REL_1_4_FINAL 1.3 REL_1_3_FINAL 1.2.1 (bugfix1) REL_1_2_1_FINAL 1.2 REL_1_2_FINAL 1.1.2 (bugfix3) REL_1_1_2_BASE 1.1.1 (bugfix2) REL_1_1_1_BASE 1.1 (bugfix1) REL_1_1_BASE To get a complete list of allowed tags, type cvs stat -v README. Many of the tags are not generally useful. Once you have done an update with -r tagname, you have made a "sticky tag." The stickiness refers to the fact that CVS remembers which tag you have used most recently. The tag is stored in the CVS subdirectory, so it stays around even if you log off and return later. After creating a sticky tag, any future cvs updates will try to keep your directory in sync with the version you chose. In other words, when developers check in changes you will not see them because your directory is "stuck" looking at an old version. To clear the sticky tag, use cvs update -A. A variation on the sticky tag concept is a sticky date According to some sources, this is when you eat dinner with someone, and accidentally spill a drink on him/her. . If some feature was working at some time in the past, but is no longer working, you can ask CVS to give you the sources from any date. cvs update -D 2001-06-14 will download the Bochs source as they were on June 14, 2001. Again, use -A to clear the sticky date and track the current sources.

Entire books have been written on CVS, so there's no sense in duplicating it all here in the Bochs documentation. Some sources of additional information are listed below. The cvshome.com site has tons of CVS FAQs and documentation, including the official CVS manual by Per Cederqvist. Another CVS FAQ is available at University of Utah.

This section is divided up by platform, since installing a binary package is different on different platforms.

The Bochs binaries for Windows are distributed in an EXE installer package. The Bochs installer can be started like any other Windows program and it brings up the installation wizard. Here you can select the destination folder and the installation options. The wizard installs the files and creates the registry keys, start menu and desktop links. Previous releases of Bochs were distributed as ZIP packages, too. These packages contained the same set of files as the installer package from the same version. If you are new to Bochs you should try out the DLX Linux demo distributed with Bochs. The installation wizard has created a link on the desktop if you decided to install the demo. If you doubleclick the icon two windows will appear: one is the Bochs Display window, and the other is text window that is used for the runtime configuration and for log messages if no logfile is specified. You can find more information on the DLX Linux demo in the next section below the DLX Linux screenshot. File Description BIOS-bochs-latest default ROM BIOS image for Bochs BIOS-bochs-legacy ROM BIOS image without 32-bit init code bochs.exe the main Bochs executable bochs.ico the Bochs icon (used for links in start menu and on the desktop) bochsdbg.exe the main Bochs executable with debugger enabled bochsrc-sample.txt sample Bochs configuration file bxcommit.exe tool for committing redologs to flat disk images bximage.exe tool for making new disk images CHANGES.txt what has changed between versions COPYING.txt copy of the LGPL license README.txt the read-me file from the source distribution. TODO.txt the TODO file from the source distribution. niclist.exe tool to find out the network interface name penguin.ico the Linux logo (used for the DLX link in start menu) sb16ctrl.exe tool to control sb16 in Bochs sb16ctrl.txt examples of sb16ctrl commands VGABIOS-elpin-2.40 VGA BIOS image for Bochs VGABIOS-elpin-LICENSE.txt license for VGA BIOS VGABIOS-lgpl-latest LGPL'd VGA BIOS image for Bochs VGABIOS-lgpl-latest-debug LGPL'd VGA BIOS image for Bochs with debug output to the logfile VGABIOS-lgpl-latest-cirrus LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled VGABIOS-lgpl-latest-cirrus-debug LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled and debug output to the logfile VGABIOS-lgpl-README.txt readme for the LGPL'd VGA BIOS uninstall.exe uninstall program for Bochs (created by the installation wizard) dlxlinux\ directory containing DLX linux sample disk image and configuration files dlxlinux\readme.txt description of DLX linux dlxlinux\bochsrc.txt Bochs configuration file for DLX dlxlinux/hd10meg.img disk image file (10 meg) dlxlinux\start.bat Run this BAT file to try out DLX Linux inside Bochs! dlxlinux\testform.txt Form for reporting success or failure doc\index.html a local copy of all Bochs documentation (online copy) keymaps\*.map keymap tables (on Windows used for the paste feature only)

RPM stands for "RedHat Package Manager." An RPM is a compressed file containing files to be installed on your system. Many Linux distributions, not just RedHat ones, can install files from an RPM. First, download the Bochs RPM for your architecture to your computer. For example, if you have an Intel-compatible computer, be sure to get the RPM that says "for Linux x86 distributions" or "i386". Once you have the package on your local disk, you should become the root user and install it as follows Many distributions have their own RPM installer program, often graphical, and they should work ok. It is helpful to be able to see the text output from RPM, so if you use a fancy RPM installer, be sure to find the text output and check that it looks correct. :

user$ su Password: root# ls -l bochs-1.2.1.i386.rpm -rw-rw-r-- 1 user user 1877515 Sep 14 09:02 bochs-1.2.1.i386.rpm root# rpm -i bochs-1.2.1.i386.rpm Looking for fonts to install... /usr/local/bochs/latest/ Looking for X11 Font Path... /usr/lib/X11/fonts Installing vga.pcf... ok (it was already there) Running mkfontdir... Done installing Bochs fonts for X11. root# exit user$ _

All RPM installations are done as the root user because they require permission to update system files and directories. If you do not have root access you need to compile Bochs in your home directory. RPM installation can fail for a few reasons. It will fail if you already have a Bochs package installed. In this case, try upgrading the old package to the new package with rpm --upgrade NAME.i386.rpm. Another potential problem is missing RPM dependencies. If you are getting errors about missing files or RPMs, then first you should try to install the RPMs that provide the missing pieces. If that cannot be done, download the source RPM and build a new binary RPM that is appropriate for your platform. The command is rpmbuild --rebuild NAME.src.rpm. As a last resort, you can run rpm with the --nodeps option to ignore dependencies and install it anyway, but if it is missing important pieces it may not run properly. The Bochs RPM installs four new commands and associated manual pages: bochs, bochs-dlx, bximage and bxcommit. First, let's try out the DLX Linux demo by typing bochs-dlx. user$ bochs-dlx --------------------------------------------------------------- DLX Linux Demo, for Bochs x86 Emulator --------------------------------------------------------------- Checking for bochs binary...ok Checking for DLX linux directory...ok Checking for /bin/gzip...ok Checking for /usr/users/bryce/.bochsdlx directory... --------------------------------------------------------------- To run the DLX Linux demo, I need to create a directory called /usr/users/bryce/.bochsdlx, and copy some configuration files and a 10 megabyte disk image into the directory. --------------------------------------------------------------- Is that okay? [y/n] y Copying /usr/share/bochs/dlxlinux/bochsrc.txt -> /usr/users/bryce/.bochsdlx/. Copying /usr/share/bochs/dlxlinux/README -> /usr/users/bryce/.bochsdlx/. Copying /usr/share/bochs/dlxlinux/testform.txt -> /usr/users/bryce/.bochsdlx/. Uncompressing /usr/share/bochs/dlxlinux/hd10meg.img.gz -> /usr/users/bryce/.bochsdlx/hd10meg.img Entering /usr/users/bryce/.bochsdlx Running bochs ======================================================================== Bochs x86 Emulator 2.0.pre3 Build from CVS snapshot on December 4, 2002 ======================================================================== Then you get a new X11 window containing the VGA display of the simulated machine. First you see the VGA BIOS screen, then Linux uncompresses and boots, and you get a login prompt. Type "root" and ENTER to log in to DLX linux.

Booting is complete when you see "dlx login:" and a cursor. At this login prompt, type "root". On UNIX systems, root is the system admin user. There is no password for root on this sample disk image, so it lets you log in without typing any password. Now you should see a UNIX prompt, and you can begin to type UNIX commands. Welcome to DLX V1.0 (C) 1995-96 Erich Boehm (C) 1995 Hannes Boehm dlx login: root Linux 1.3.89. dlx:~# pwd /root dlx:~# cd / dlx:~# ls bin/ etc/ lost+found/ root/ usr/ boot/ fd/ mnt/ sbin/ var/ dev/ lib/ proc/ tmp/ zip/ dlx:/# df Filesystem 1024-blocks Used Available Capacity Mounted on /dev/hda1 10060 2736 6005 29% / dlx:/# _ When you get tired of playing with DLX Linux, just type "reboot" in the Bochs window to shut down the DLX Linux operating system, and when it starts to reboot again press the "Power" button at the top of the Bochs display to end the application. Here is a list of the files that are installed by the RPM, and a brief description of each one. File Description /usr/share/doc/bochs/CHANGES what has changed between versions /usr/share/doc/bochs/COPYING copy of the LGPL license /usr/share/doc/bochs/README the read-me file from the source distribution. /usr/share/doc/bochs/TODO the TODO file from the source distribution. /usr/bin/bochs the main Bochs executable /usr/bin/bximage tool for making new disk images /usr/bin/bxcommit tool for committing redologs to flat disk images /usr/lib/bochs/plugins/* device and gui plugins for Bochs (plugin version only) /usr/share/doc/bochs/bochsrc-sample.txt sample Bochs configuration file /usr/share/man/man1/* man pages for bochs, bochs-dlx, bximage and bxcommit /usr/share/man/man5/* man page for bochsrc /usr/share/doc/bochs/index.html a local copy of all Bochs documentation ( Online copy ) /usr/share/bochs/BIOS-bochs-latest default ROM BIOS image for Bochs /usr/share/bochs/BIOS-bochs-legacy ROM BIOS image without 32-bit init code /usr/share/bochs/VGABIOS-elpin-2.40 VGA BIOS image for Bochs /usr/share/bochs/VGABIOS-elpin-LICENSE license for VGA BIOS /usr/share/bochs/VGABIOS-lgpl-latest LGPL'd VGA BIOS image for Bochs /usr/share/bochs/VGABIOS-lgpl-latest-debug LGPL'd VGA BIOS image for Bochs with debug output to the logfile /usr/share/bochs/VGABIOS-lgpl-latest-cirrus LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled /usr/share/bochs/VGABIOS-lgpl-latest-cirrus-debug LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled and debug output to the logfile /usr/share/bochs/VGABIOS-lgpl-README readme for the LGPL'd VGA BIOS /usr/bin/bochs-dlx run this script to try out DLX Linux inside Bochs! /usr/share/bochs/dlxlinux/ directory containing DLX linux sample disk image and configuration files /usr/share/bochs/dlxlinux/readme.txt description of DLX linux /usr/share/bochs/keymaps/*.map keymap tables for X11 and SDL

This was contributed by Aard Vark in January 2003 The MacOS X binary distribution is a mountable disk image (.dmg file). Once you've downloaded the binary distribution file, just double click on it to automatically unpack the archive and mount the volume on the desktop. An icon will appear exactly as if you'd inserted a CD-ROM or removable storage device, and a finder window containing the volume should automatically open. It is likely to have an odd name such as _dmg_top, but don't worry about that. Copy the Bochs-2.0 (or whatever version) folder from the disk image onto your hard disk. Either Home or Applications would be sensible places to put it. Because the disk image is mounted read only, you can't run the included dlxlinux guest OS until you've copied it to the hard disk. Once you've installed the binaries, it's probably a good idea to drag the _dmg_top volume to trash to unmount it, so you don't get confused and try to run bochs from there. Then open the bochs folder from wherever you installed it. The MacOS X version of bochs requires a terminal window to run. If you just double click on the Bochs icon, you'll get an error message telling you to double click on "bochs.scpt" to start Bochs in a new terminal window. You'll need to configure Bochs before you will get very far with the bochs.scpt in the top folder, so to try out bochs open the dlxlinux folder and double click on the bochs.scpt icon inside. This will open a new terminal window which will contain the Bochs startup messages, and a configuration menu. The default option is [5], which starts the simulation, so press enter to do so. You will then get a new window containing the VGA display of the simulated machine. The new window will probably appear behind the current terminal window, so either click on the bochs icon in the dock or the simulation window to bring it to the front. If you're quick enough you'll then see the VGA BIOS screen, then Linux uncompresses and boots, and you get a login prompt. Type "root" and ENTER to log in to DLX Linux. Once you've finished playing with DLX Linux, just type "reboot" in the Bochs window to shut down the DLX Linux operating system, and when it starts to reboot again press the "Power" button in the "MacBochs Hardware Controls" window (it's the circle containing a vertical bar at the far right - have a look at the Linux screenshots, since the Mac version doesn't seem to have descriptions or tool-tips).

Bochs is written in C++, so you need a C++ compiler on your system. Most platforms have been tested with GNU gcc/g++, but other compilers are known to work too. By now, you should have unpacked your source TAR file or checked out Bochs from CVS. If not, you can return to Downloading Bochs for details. The top level directory of the source code will be referred to as &bochsdir;. (&bochsdir; contains the files bochs.h and main.cc and subdirectories cpu and bios.) The standard compile process has three basic steps: configure, make, and make install. Each step is described in a separate section below. The standard compile process is used on all Unix machines, MacOS X, BeOS, and Cygwin (win32). There are separate instructions for compiling for Win32 with Microsoft VC++.

There is a script called configure which tests your machine, C/C++ compiler and libraries to discover what settings should work on your system. If you run configure with no arguments after it, defaults will be used for all settings. To change the settings, you can run configure with options that override the defaults. You can get a list of valid configure options by typing configure --help. One useful configure option is --prefix=directory, which sets the directory in which Bochs will be installed. All the possible configure options are documented in a later section. Among other things, the configure script tries to detect your platform and which compile options to use. If you want to control this, set these environment variables before running configure: CC, CXX, CFLAGS, CXXFLAGS. Here is an example that sets the environment variables, using bash/ksh The syntax for bash and ksh is given. In csh and variants, use the syntax setenv VARIABLE value to change environment variables. Do not use an equal sign for csh! syntax: export CC=egcs export CXX="$CC" export CFLAGS="-Wall -O2 -m486 -fomit-frame-pointer -pipe" export CXXFLAGS="$CFLAGS" Once the configure script knows what options are selected, it creates a Makefile in every source code directory, and creates $BOCHS/config.h with all the option values written as preprocessor #defines. Now the sources are ready to compile.

In the Bochs source directory, you will see a series of scripts called .conf.platform. These scripts run the configure script for you, with a set of options that are appropriate for that platform. It is not necessary to use the shortcut scripts; they are simply there to show you an example that the developers have used. Some of these scripts have been used to build official binary packages. If a shortcut script is "almost right" for you, just edit it and then run it! If you run a shortcut script, you don't need to run configure manually. Run a shortcut script using Bourne shell, like this: sh .conf.win32-vcpp These .conf.platform have been tested in recent Bochs versions: .conf.linux .conf.sparc .conf.macos .conf.macosx .conf.win32-vcpp .conf.win32-cygwin .conf.beos

The make command compiles Bochs. Make is a program used by many software projects that reads the &Makefile; in each source directory and follows the instructions that it finds there. A &Makefile; tells which files depend on which other files, what commands to use to compile and link the code, and more. After you have finished the configure step, just type make to build the source code. The reason that make is so popular is that it is smart about when to compile and when not to compile. If you run make once, it compiles every file. But when you run it again, it checks to see if any source files have been modified; if not, there's nothing to do! For example, the &Makefile; says that main.o depends on main.cc. Knowing this, it will only compile main.cc if it is newer than main.o. Of course, make can only do the right thing if the &Makefile; lists all the dependencies correctly, so human error can sometimes lead make astray. If make refuses to build something that you think it should, or you are getting strange compile errors, try doing make all-clean and then make again. All-clean means to clean up the compiled files in every subdirectory, while make clean means to clean up just the current directory This is different from the terminology of some other projects, and it may cause confusion. Sometimes "clean" implies that all subdirectories are affected. . However, it's important to note that make all-clean leaves the configuration intact. You do not have to run configure again. If you're really in the mood for cleaning, make dist-clean erases all the configuration information too. In theory, after a dist-clean your directory should look much like when you first untarred it or checked it out. There's usually some extra stuff lying around, but the &Makefile; tries at least to erase any files that it created.

Once the program has been built, the next step is typically to run make install to copy the executables, documentation, and other required files into a public place so that all users can use it. By default the files are copied to some directories in /usr/local. The following tables shows the directories and their contents. &FIXME; make install_dlx option bin binary executables (bochs, bxcommit, bximage) lib/bochs/plugins plugins (if present) man/man1 manpages for installed binaries man/man5 manpage for the config file (bochsrc) share/bochs BIOS images, VGABIOS images, keymaps share/doc/bochs HTML docs, license, readme, changes, bochsrc sample

This section describes the configure options for Bochs. Perhaps the most important option is --help, since it gives you a list of all the other options. The configure script will detect your platform and choose the default GUI for your platform. If the default choice is not what you want, use the --with-* options to override the default. The options in the first table tell which GUI library is the default for each platform. Starting in version 2.0, you can use multiple --with-* options at once to compile with multiple display libraries, and then choose between them at runtime with the display_library option in the configuration file. Or, you can let the configure script detect which libraries are on your system and use them all, by configuring with --with-all-libs. The concept of platform detection and default GUIs was added in Bochs 1.4. In Bochs 1.3 and before, the X11 GUI was always the default. Platform Default GUI Extra compile flags win32, Cygwin or MinGW/MSYS --with-win32 If using nmake method, compile using cl /nologo /MT /W3 /EHs-c- /DNDEBUG /DWIN32 /D_WINDOWS /D_CRT_SECURE_NO_WARNINGS. If using Visual C++ workspace, see the workspace file for compile settings. See Compiling on Win32 with Microsoft VC++ for instructions. MacOS X or Darwin --with-carbon -fpascal-strings -fno-common -arch ppc -Wno-four-char-constants -Wno-unknown-pragmas -Dmacintosh MacOS 9 or before --with-macos none BeOS --with-beos none AmigaOS --with-amigaos none any other platform --with-x11 none Option Comments --with-x11 Use X windows user interface. On many operating systems, Bochs will use X windows by default. --with-win32 Use the native Win32 GUI. This is the default on win32 platforms. --with-carbon Compile for MacOS X with the Carbon GUI. See the .conf.macosx file for the correct MacOS X compile options. --with-amigaos Compile for Amiga MorphOS. This code is written by Nicholai Benalal. --with-rfb Enable support for the RFB protocol to talk to AT&T's VNC Viewer. Refer to for details. --with-sdl Enable support for the SDL GUI interface; see . --with-beos Use BeOS GUI. The configure script will run natively on BeOS; use this option when doing so. --with-term Use text-only gui with curses library. Almost certainly won't work right with the debugger or the control panel. --with-macos Use Macintosh/CodeWarrior environment. This is for running configure on a platform which supports running configure, so that you may then transfer the configured code over to the real compile environment. --with-wx Enable support for wxWidgets configuration and display interface; see . --with-svga Use SVGALIB library for Linux. This allows a full-screen text and graphics display without X windows. The SVGALIB port was written by Igor Popik. --with-nogui No native GUI; just use blank stubs. This is if you don't care about having video output, but are just running tests. --with-all-libs Automatically detect which libraries are installed on your system and enable them. This option is still experimental; it might enable libraries that are not usable and cause the compile to fail. If you have trouble, just list the --with-* options for the specific display libraries that you want. The remaining options can generally be used with any GUI. For each option such as --enable-cdrom, you can also write --disable-cdrom to explicitly turn it off. &NEEDHELP; Link CPU link to the proper row, not to the beginning of the whole table, as it is now. Option Default Comments --enable-cpu-level={3,4,5,6} 6 Select which CPU level to emulate. Choices are 3,4,5,6 which mean to target 386, 486, Pentium, or Pentium Pro and later emulation. --enable-smp no Compile in support for SMP simulation. This allows you to boot Linux and maybe other OSes in SMP mode, and bochs will simulate all the different CPUs and communication between them. Do not expect this option to speed up your simulation! On the contrary, it has to spend extra time simulating the different CPUs (even if they're mostly idle) and the communication between them. Use it to try out an SMP OS if you don't have an SMP machine, or to debug SMP OS drivers. Refer to for more details on SMP in Bochs. --enable-fpu yes If you want to compile Bochs to make use of the FPU emulator written by Stanislav Shwartsman, use this option. --enable-x86-64 no Add support for x86-64 instruction set, written by Peter Tattam and Stanislav Shwartsman. --enable-vmx no Intel Virtualization Extensions (VMX) support --enable-avx no AVX instructions support --enable-x86-debugger no X86 debugger support. If the software you run in bochs needs to use the x86 hardware debugging facilities such as DR0..DR7, instruction and data breakpoints etc., then you should use this option. Otherwise don't use it, as it will slow down the emulation. --enable-monitor-mwait no MONITOR/MWAIT instructions support (still experimental) --enable-misaligned-sse no support for AMD's misaligned SSE extension --enable-configurable-msrs no support for user configurations of emulated MSR registers (see example in msrs.def) --enable-long-phy-address no support for guest physical address larger than 32 bit --enable-cdrom yes Enable use of a real CDROM. The cdrom emulation is always present, and emulates a drive without media by default. You can use this option to compile in support for accessing the media in your workstation's cdrom drive. The supported platforms are Linux, Solaris, FreeBSD, OpenBSD, and Windows. For other platforms, a small amount of code specific to your platform must be written. The module iodev/cdrom.cc is the place to add more support. For the most part, you need to figure out the right set of ioctl() calls. --enable-sb16 no Enable Sound Blaster emulation. The lowlevel sound interface is autodetected. See section Sound Blaster 16 Emulation for supported platforms and more info. This option also enables the standard PC gameport which is a part of the SB16. If you don't want to use it, you might use --disable-gameport. --enable-es1370 no Enable ES1370 sound emulation. Just like the SB16 option, the lowlevel sound interface is autodetected and the gameport is turned on. --enable-gameport no Enables the standard PC gameport. This option is only necessary if you want to have a gameport, but no SB16 (see above). The connection to a real joystick is currently supported on Linux and win32 only. --enable-idle-hack no Enables Roland Mainz's experimental idle code, which is intended to keep Bochs from always using 100% of CPU time. When Bochs is waiting around for an interrupt, the idle code uses a select() loop and some X11 tricks to wait until user input arrives. This is designed to keep Bochs responsive while still yielding to other processes when Bochs is idle. It only works with X11 or term GUI. --enable-ne2000 no Enable NE2000 network card support. This requires a low-level component to be written for each OS. The NE2000 option is only supported on FreeBSD, OpenBSD, Linux, and Windows 9x/NT/2K/XP. When enabled and configured, the NE2000 device model can talk to any computer on the network EXCEPT FOR the local host. Exception: Under most circumstances, Bochs can talk to the local host on Windows, and in the ethertap interface for Linux. --enable-pnic no Enable PCI pseudo NIC (network card) support. --enable-clgd54xx no Enable Cirrus Logic GD54xx (CL-GD5430 ISA or CL-GD5446 PCI) video card support. For more information see . --enable-plugins no Plugins are shared libraries that can be loaded on demand. Example: the serial device is implemented as a plugin. In Unix, the serial plugin is called libbx_serial.so. When Bochs reads its configuration file, if the serial device is enabled it loads libbx_serial.so. See the Features section for supported platforms. --enable-repeat-speedups no support repeated I/O and memory copy speedups --enable-trace-cache no support instruction trace cache for faster execution --enable-host-specific-asms yes support for running native x86 instructions on an x86 machine --enable-fast-function-calls no support for fast function calls (gcc on x86 only) --enable-all-optimizations no Turn on the enables for all speed optimizations that the developers believe are safe to use: --enable-trace-cache, --enable-repeat-speedups, --enable-host-specific-asms, --enable-fast-function-calls. --enable-debugger no Compile in support for Bochs internal command-line debugger. This has nothing to do with x86 hardware debug support. It is a more powerful and non-intrusive native debugger. Enabling this will of course slow down the emulation. You only need this option if you know you need it. After you have run ./configure, you may want to edit config.h to customize the debugger further; see for more information. --enable-readline detected by configure Compile the debugger with the GNU readline library, which gives command line editing and history. --enable-disasm yes Compile in support for built-in disassembler. Bochs has a built-in disassembler, which is useful if you either run the built-in debugger (--enable-debugger), or want disassembly of the current instruction when there is a panic in bochs. --enable-cpp no Use .cpp as C++ suffix. Renames all the .cc files to .cpp for use with compilers which want that, like older MS C++ compilers. Don't use this option unless you know you need it. --enable-docbook detected Build the docbook documentation in doc/docbook. The configure script will enable this option automatically if you have a program called docbook2html installed. --enable-iodebug yes if debugger is on Dave Poirier has written an experimental interface to the debugger using I/O ports, so that software running in the guest OS can access features of the debugger. You only want this option if you are developing guest OS code for use in Bochs. In other words, most people don't. Also, it should only be used with --enable-debugger. See the developer documentation for details. --enable-compressed-hd no Add support for compressed disk (not implemented yet). zlib must be installed on your system, as it will be dynamically linked to Bochs. --enable-pci no Enable limited i440FX PCI support. This is still incomplete, but usable. --enable-pcidev no Enable PCI host device mapping support. This requires --enable-pci to be set as well as Linux 2.4 or 2.6 as host. --enable-usb no Enable i440FX PCI USB support (UHCI). The host controller with 2-port root hub and 6 USB device types are available. --enable-usb-ohci no Enable experimental USB OHCI support. The host controller with 2-port root hub is available (USB device types: same as UHCI). --enable-instrumentation=directory no Compile in support for instrumentation. This allows you to collect instrumentation data from bochs as it executes code. You have to create your own instrumentation library and define the instrumentation macros (hooks in bochs) to either call your library functions or not, depending upon whether you want to collect each piece of data. [Kevin wrote: I broke some of the hooks when I recoded the fetch/decode loop.] --enable-xpm yes Enables the check for the XPM library. This option is only valid if the x display library is enabled (--with-x11). --enable-show-ips no Enables logging of measured IPS, see the ips parameter of the cpu option.

user$ ls -l bochs-1.2.1.tar.gz -rw-rw-r-- 1 user user 887993 Sep 15 23:24 bochs-1.2.1.tar.gz user$ gunzip -c bochs-1.2.1.tar.gz | tar -xvf - bochs-1.2.1/ bochs-1.2.1/bios/ bochs-1.2.1/bios/BIOS-bochs-2-processors bochs-1.2.1/bios/Makefile.in . . . bochs-1.2.1/patches/NOTES bochs-1.2.1/patches/patch.4meg-pages bochs-1.2.1/patches/patch.goswin-changes user$ cd bochs-1.2.1 user$ ./configure --enable-cdrom creating cache ./config.cache checking for gcc... gcc checking whether the C compiler (gcc ) works... yes checking whether the C compiler (gcc ) is a cross-compiler... no checking whether we are using GNU C... yes checking whether gcc accepts -g... yes . . . creating misc/Makefile creating dynamic/Makefile creating fpu/Makefile creating config.h user$ make cd iodev && \ make CC="gcc" CXX="c++" CFLAGS="-g -O2 " CXXFLAGS="-g -O2 " LDFLAGS="" LIBS="" X_LIBS="-L/usr/X11R6/lib" X_PRE_LIBS="-lSM -lICE" prefix="/usr/local" exec_prefix="/usr/local" bindir="/usr/local/bin" infodir="" libiodev.a make[1]: Entering directory `/tmp/bochs-1.2.1/iodev' c++ -c -g -O2 -I.. -I../instrument/stubs devices.cc -o devices.o c++ -c -g -O2 -I.. -I../instrument/stubs pic.cc -o pic.o c++ -c -g -O2 -I.. -I../instrument/stubs pit.cc -o pit.o c++ -c -g -O2 -I.. -I../instrument/stubs unmapped.cc -o unmapped.o c++ -c -g -O2 -I.. -I../instrument/stubs cmos.cc -o cmos.o . . . echo done done c++ -o bochs -g -O2 main.o load32bitOShack.o state_file.o pc_system.o osdep.o \ iodev/libiodev.a \ cpu/libcpu.a memory/libmemory.a gui/libgui.a \ fpu/libfpu.a \ -L/usr/X11R6/lib -lSM -lICE -lX11 gcc -c -g -O2 -I. -Iinstrument/stubs misc/bximage.c -o misc/bximage.o c++ -o bximage -g -O2 misc/bximage.o user$ su root# make install cd iodev && \ make CC="gcc" CXX="c++" CFLAGS="-g -O2 " CXXFLAGS="-g -O2 " LDFLAGS="" LIBS="" X_LIBS="-L/usr/X11R6/lib" X_PRE_LIBS="-lSM -lICE" prefix="/usr/local" exec_prefix="/usr/local" bindir="/usr/local/bin" infodir="" libiodev.a make[1]: Entering directory `/tmp/bochs-1.2.1/iodev' . . . /usr/local/bochs/1.2.1/install-x11-fonts Looking for fonts to install... font/ Looking for X11 Font Path... /usr/lib/X11/fonts Installing vga.pcf... ok (it was already there) Running mkfontdir... Done installing Bochs fonts for X11. root# exit user$ _

The standard compile uses the configure script, but the Windows platform cannot run the configure script natively. The current solution to this problem is that the Bochs configure script must be run on a different platform that does support shell scripts, with options that cause it to configure for a Win32 platform instead of the native one. Many people have access to a UNIX machine that could run the configure script, or you can use Cygwin or MinGW/MSYS to run the configure script. Because Bochs depends so much on the configure script, if you are doing much win32 Bochs development, you should consider downloading Cygwin or MinGW/MSYS so that you can run the configure step natively. . Download the Bochs sources on a machine that can run shell scripts. Edit the configure shortcut script .conf.win32-vcpp if you want to adjust the configure options. Then type these commands in the Bochs source directory: sh .conf.win32-vcpp make win32_snap These commands will run the configure step, produce VC++ makefiles and workspace files, and pack it all into a .zip file in the directory above the source directory If the source directory is /home/joe/bochs-win32, the resulting .zip file is in /home/joe/bochs-win32-msvc-src.zip. . The .zip file is all ready to transfer to the target Windows machine to be unzipped and compiled. Or, if you run the sh/make steps in Cygwin, you are already on the target machine so you don't need the .zip file. When you have the Win32 sources transferred to a Windows machine with VC++, find the workspace file called bochs.sln in the folder "vs2008" and load it in VC++. Choose Project:Set Active Project and be sure that "bochs" is selected. Then choose Build:Build bochs.exe. This will build all the required libraries (iodev, cpu, etc.) and the auxiliary programs bximage.exe, bxcommit.exe and niclist.exe. Using workspaces is easy and intuitive, but there is one caveat. The workspaces come directly out of a ZIP file in build/win32/vs2008ex-workspace.zip, and they are not controlled by the configure script. When you compile with certain configure options (e.g. --with-sdl) you need to link with additional libraries. For now you must add them to the VC++ workspace by hand. In version 2.0, we have improved the situation considerably by adding #if...#endif around every optional file and including nearly every Bochs source file in the workspace. This solves the problem of having to manually add source files to the workspace when you turn on configure options such as --enable-debugger. The problem of adding link libraries remains unresolved. To compile with the Bochs debugger enabled, add "--enable-debugger" to the configure line in .conf.win32-vcpp before running it. No modifications to the workspace are necessary. An alternative way to compile is to run nmake.exe in an MS-DOS window. Instead of using the workspace files, nmake uses the Bochs makefiles that are generated by configure. The workspace file was new in version 1.3; before that, nmake was the only way to compile Bochs in VC++. Starting with version 1.4, the workspace is used to build the release binaries. The make install for Win32 is presently broken. In the future, a make install that runs in Cygwin may be provided.

Cygwin is a free Unix-like environment for Windows written by Steve Chamberlain and now maintained by RedHat, Inc. You can download it from www.cygwin.com. Because Cygwin supports the configure script and uses GNU gcc/g++, you can use the standard compile process. The configure script should automatically detect Cygwin and add "-mno-cygwin -DWIN32" to the compiler options. You should get a working Bochs if you just type: configure make Optionally, you can use the configure shortcut script for Cygwin, .conf.win32-cygwin, instead of running configure directly. If this script is close to what you need, just edit the script and then run it. To use the configure shortcut script and compile in Cygwin, the commands are sh .conf.win32-cygwin make To find out the options which are known to work in Cygwin, open the file .conf.win32-cygwin in any text editor/viewer and have a look at the end of that file.

It is possible that this hasn't been tried since 1999. In theory, you run sh .conf.macos on a Unix box to build the makefiles and headers, copy the whole thing over to a Mac, and then use CodeWarrior to compile. Since it hasn't been tested in so long, it is quite likely that some work is needed to bring the Mac port up to date. If you are interested and have the required MacOS development tools, please let us know by contacting the &devlist;. Someone requests a MacOS port almost once a month, but none of the developers know how to help them.

The port to MacOS X with Carbon API by Emmanuel Mailliard is quite new, and the configure and makefile support was added by Bryce Denney. You will need the compiler and libraries from the development tools CD. Bochs should configure and compile with the Carbon GUI if you simply type: configure make Optionally, you can use the configure shortcut script for MacOS X, .conf.macosx, instead of running configure directly. If this script is close to what you need, just edit the script and then run it. To use the configure shortcut script and compile, the commands are sh .conf.macosx make MacOS X has a special format for an application bundle, which looks like a directory that contains the required resource files and binaries. The Makefile currently creates this application bundle "by hand" using mkdir and copy, which is surely the wrong way to do it. Bryce doesn't know the official way to create an application from a Makefile, so this hack will remain until a real Mac developer helps to clean it up. On MacOS X the default GUI is the Carbon interface, but you can also try other Bochs GUIs. Use --with-x11 for X windows, --with-rfb for VNC/RFB, or --with-sdl for SDL.

Kevin Lawton ported Bochs to BeOS. Bernd Korz has taken over the port. Since Bochs 1.4, you can use the same compile and install process as on Unix, that is, configure will detect the BeOS platform and assume you want the BeOS GUI. configure make Optionally, you can use the configure shortcut script for BeOS, .conf.beos, which uses the SDL GUI by default.

Nicholai Benalal created this port to MorphOS running on Amiga. It should compile with: configure make If the platform is not detected properly, you might need to use --enable-amigaos as a configure option. Optionally, you can use the configure shortcut script, .conf.amigaos.

The RFB code was written by Don Becker x-odus@iname.com, who has a Bochs-RFB web page on his site, http://www.psyon.org/bochs-rfb/. This interface allows you to view the Bochs display with AT&T's VNC Viewer. The protocol used between a VNC server and a VNC viewer is called RFB. Because the RFB code in Bochs is written with portable network socket and POSIX thread code, it can be compiled on many platforms and has been tested in Linux and Win32. No additional libraries are required. To try it, type: configure --with-rfb make RFB currently uses this setup: port range 5900 to 5949 (using the first one available) no authentification 30 seconds waiting for client 8 bpp (BGR233) supported only desktop size 720x480 (for text mode and standard VGA)

Dave Poirier has written an SDL interface for Bochs. Simple DirectMedia Layer, or SDL, is a cross-platform multimedia library distributed from libsdl.org. SDL is available for many platforms including Win32, Linux, BSD, IRIX, MacOS, MacOS X, BeOS, and AmigaOS. To compile Bochs with SDL, you must first install the SDL library from libsdl.org. You can either get the source code and compile it yourself, or install the development libraries for your platform (already compiled). Then, go into the Bochs directory and type: configure --with-sdl make If you are on FreeBSD and have SDL installed using the ports collection, Bochs won't be able to find the library automatically, as the SDL config script is called sdl11-config in that case (even for version 1.2). The easiest way to make Bochs find it, is to create a symlink to that script called sdl-config inside a directory which is in the path. For example: ln -s /usr/local/bin/sdl11-config ~/bin/sdl-config To compile in Microsoft VC++, you have to configure on a different system. Here's the procedure: - On a machine that can run shell scripts, such as Cygwin, run configure --target=pentium-windows --with-sdl make win32_snap - Copy the resulting ZIP file to your Windows box and unzip it. - Load up workspace called bochs.dsw in VC++ 6.0 - Double click "gui files" - Remove gui/win32.cpp from the project, and add gui/sdl.cpp instead. - Edit the settings of "gui files". Under C/C++ tab, category=preprocessor, additional include directories, add the directory where SDL/SDL.h can be found. - Edit the settings of the "bochs files" project. Under the Link tab, category=General, add SDL.lib to object/library modules list. Then in category=Input, add the path of SDL.lib to additional library path. Click ok. - Select Build:Build Bochs.exe

wxWidgets is a cross-platform C++ user interface library which you can download for free at wxwidgets.org. The wxWidgets port of Bochs provides both a graphical configuration interface for editing bochsrc options (see config_interface option) and a display (see display_library option). It was written by Bryce Denney, Don Becker, Dave Poirier, and Volker Ruppert. configure --with-wx make If you want Bochs to use a wxWidgets installation not in your path (but installed somewhere else), you need to set the WX_CONFIG environment variable to the proper wx-config script, before running configure (example for csh): setenv WX_CONFIG '/home/compile/wx/bin/wx-config'

RPM stands for "RedHat Package Manager." An RPM is a compressed file containing files to be installed on your system. Bochs has a special shell script called make-rpm that helps to build an RPM of Bochs. Start with a clean source directory. Edit .conf.linux first if you want to adjust the configure options. Then, type: ./build/redhat/make-rpm | tee /tmp/build.txt When this command completes, you should have a source RPM and a binary RPM of Bochs in the current directory. The tee part of the command (optional) saves a transcript of the build process into /tmp/build.txt, which is very useful if anything goes wrong. Instructions for installing an RPM are here. In the past, you had to build rpms as root, but as of version 2.0 you can build them as a normal user.

&FIXME; what if configure fails? - tar up config.* and send to bochs-developers - report the problem with a source forge bug report. what if make fails? - try make dist-clean, and run configure and make again - use configure options to disable options. For example, if errors in fpu/fpu.cc, you could try --disable-fpu. - search for the error on the Bochs website (bug reports, patches) - if familiar with C++, many minor problems can be corrected - move to more stable code. if it's CVS, see if a release version will compile. Report problem to bochs-developers. - report the problem with a source forge bug report.

These are the minimum requirements for running an OS inside of Bochs: the Bochs executable the BIOS image (usually called BIOS-bochs-latest) the VGA BIOS image (e.g. VGABIOS-lgpl-latest or VGABIOS-elpin-2.40) at least one bootable media, either as disk image (floppy, hard disk or CD-ROM) or physical disk (floppy or CD-ROM) Both VGA BIOS versions as well as the ROM BIOS are part of Bochs. No separate download is necessary. If you want to use the Cirrus SVGA adapter instead of VGA + Bochs VBE, you should have a look at . In that case you have to pass the configuration options on the command line or to use the configuration interface to set up Bochs for the simulation. Running Bochs is easier if you use a configuration file (we call it bochsrc). See for all supported options. The easiest way to setup Bochs for the first time is to use the example configuration file called bochsrc-sample.txt. Locate that file (location depends on the (host) OS and on the installation facility used) and copy it to a location where Bochs looks for that file, see . The next step is to change the configuration so that it fits your needs: You most likely want to setup a hard disk (see and ), and install some OS on it using either a set of floppy disks (see ) or a CD-ROM (see again) as installation media. Make sure you boot the emulation from the media you want, using the right setting as boot option. If your keyboard output inside of Bochs is wrong, you may also need a keymap file to remap your keyboard layout to the U.S. layout. A set of keymap files for the X window system and SDL (Linux port) is distributed with Bochs. If your keyboard layout is not supported yet, you can create your own one by following the instructions given in . A collection of disk images of different operating systems can be found at . Some disk images are the size of a floppy disk (1 meg compressed) and others are gigantic (160 meg compressed). If you want to create a disk image yourself, please see . &FIXME; This should be completed - BIOS/VGABIOS, what do they do?

Bochs uses a configuration file called bochsrc to know where to look for disk images, how the Bochs emulation layer should work, etc. When you first start up Bochs, it looks around for its configuration file (see ), and parses it. Here are a few lines from a sample file: ata0-master: type=disk, path="30M.sample", cylinders=615, heads=6, spt=17 boot: disk The format is very strict, so be sure to put the right number of spaces and use lowercase letters. As you can see, most lines have a keyword telling what is being configured, followed by a colon, followed by a few variable=value pairs, separated by commas. For very simple options, sometimes just a single value is needed. The source and binary distributions come with a sample bochsrc, so you can just copy the sample file and edit the settings you need to change. The syntax used for bochsrc can also be used as command line arguments for Bochs. If you have any spaces in your command line arguments, they should be enclosed in single quotes, for example: bochs 'boot:floppy' 'floppya: 1_44=a.img, status=inserted' For other arguments, see section Command line arguments. Starting with version 1.3, you can use environment variables in the bochsrc file, for example: floppya: 1_44="$IMAGES/bootdisk.img", status=inserted boot: floppy Starting with version 2.0, two environment variables have a built-in default value which is set at compile time. $BXSHARE points to the "share" directory which is typically /usr/local/share/bochs on UNIX machines. See the $(sharedir) variable in the Makefile for the exact value. $BXSHARE is used by disk images to locate the directory where the BIOS images and keymaps can be found. If $BXSHARE is not defined, Bochs will supply the default value. Also, $LTDL_LIBRARY_PATH points to a list of directories (separated by colons if more than one) to search in for Bochs plugins. A compile-time default is provided if this variable is not defined by the user. On Win32 and MacOSX, the default for the share directory is determined by a platform-specific specific algorithm. On Win32, we use the registry to see what directory Bochs and its support files were installed in. On MacOSX, the share directory is the directory where the application is located. Starting with version 2.0, you can can use #include in the bochsrc to read the configuration from other files. Now it is possible to put platform or installation defaults in a global config file (e.g. location of rom images). Put this on top of your config file if the global configuration is stored in /etc: #include /etc/bochsrc The section below lists all the supported bochsrc options.

Examples: megs: 32 megs: 128 Set the number of megabytes of physical memory you want to emulate. The default is 32MB; most OS's won't need more than that. The maximum amount of memory supported is 2048MB. Due to limitations in the host OS, Bochs fails to allocated even 1024MB on most systems.

Example: cpu: count=2, ips=10000000 This defines the parameters of the cpu inside Bochs: count Set the number of processors:cores per processor:threads per core when Bochs is compiled for SMP emulation. Bochs currently supports up to 8 processors. If Bochs is compiled without SMP support, it won't accept values different from 1. For more information on SMP see . quantum Maximum amount of instructions allowed to execute by processor before returning control to another cpu. This option exists only in Bochs binary compiled with SMP support. reset_on_triple_fault Reset the CPU when triple fault occur (highly recommended) rather than PANIC. Remember that if you are trying to continue after triple fault the simulation will be completely bogus ! msrs Define path to user CPU Model Specific Registers (MSRs) specification. See example in msrs.def. ignore_bad_msrs Ignore MSR references that Bochs does not understand; print a warning message instead of generating #GP exception. This option is enabled by default but will not be avaiable if configurable MSRs are enabled. ips Emulated Instructions Per Second. This is the number of IPS that Bochs is capable of running on your machine. You can recompile Bochs with --enable-show-ips option enabled, to find your workstation's capability. Measured IPS value will then be logged into your log file or in the status bar (if supported by the gui). IPS is used to calibrate many time-dependent events within the Bochs simulation. For example, changing IPS affects the frequency of VGA updates, the duration of time before a key starts to autorepeat, and the measurement of BogoMips and other benchmarks. The table below lists some typical IPS settings for different machinesIPS measurements depend on OS and compiler configuration in addition to processor clock speed.. Bochs Speed Machine/Compiler Typical IPS 2.3.73.2GhzIntel Core 2 Q9770 with WinXP/g++ 3.4 50 to 55 MIPS2.3.72.6GhzIntel Core 2 Duo with WinXP/g++ 3.4 38 to 43 MIPS2.2.62.6GhzIntel Core 2 Duo with WinXP/g++ 3.4 21 to 25 MIPS2.2.62.1GhzAthlon XP with Linux 2.6/g++ 3.4 12 to 15 MIPS2.0.11.6GhzIntel P4 with Win2000/g++ 3.3 5 to 7 MIPS

Example: cpuid: mmx=1, sep=1, sse=sse4_2, apic=xapic, aes=1, movbe=1, xsave=1, cpuid_limit_winnt=0 This defines features and functionality supported by Bochs emulated CPU: mmx Select MMX instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 5. apic Select APIC configuration (LEGACY/XAPIC/X2APIC). This option exists only if Bochs compiled with BX_CPU_LEVEL >= 5. sep Select SYSENTER/SYSEXIT instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. sse Select SSE instruction set support. Any of NONE/SSE/SSE2/SSE3/SSSE3/SSE4_1/SSE4_2 could be selected. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. aes Select AES instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. movbe Select MOVBE Intel(R) Atom instruction support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. xsave Select XSAVE extensions support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. xsaveopt Select XSAVEOPT instruction support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. avx Select AVX instruction set support. This option exists only if Bochs compiled with --enable-avx option. 1g_pages Enable 1G page size support in long mode. This option exists only if Bochs compiled with x86-64 support. pcid Enable Process-Context Identifiers (PCID) support in long mode. This option exists only if Bochs compiled with x86-64 support. mwait Select MONITOR/MWAIT instructions support. This option exists only if Bochs compiled with --enable-monitor-mwait. mwait_is_nop When this option is enabled MWAIT will not put the CPU into a sleep state. This option exists only if Bochs compiled with --enable-monitor-mwait. family Set family information returned by CPUID. Default family value determined by configure option --enable-cpu-level. model Set model information returned by CPUID. Default model value is 3. stepping Set stepping information returned by CPUID. Default stepping value is 3. vendor_string Set the CPUID vendor string returned by CPUID(0x0). This should be a twelve-character ASCII string. brand_string Set the CPUID brand string returned by CPUID(0x80000002 .. 0x80000004]). This should be at most a forty-eight-character ASCII string. cpuid_limit_winnt Determine whether to limit maximum CPUID function to 3. This mode is required to workaround WinNT installation and boot issues.

Examples: romimage: file=bios/BIOS-bochs-latest, address=0xe0000 romimage: file=$BXSHARE/BIOS-bochs-legacy, address=0xf0000 romimage: file=mybios.bin, address=0xfff80000 romimage: file=mybios.bin The ROM BIOS controls what the PC does when it first powers on. Normally, you can use a precompiled BIOS in the source or binary distribution called BIOS-bochs-latest. The default ROM BIOS is usually loaded starting at address 0xe0000, and it is exactly 128k long. The legacy version of the Bochs BIOS is usually loaded starting at address 0xf0000, and it is exactly 64k long. You can also use the environment variable $BXSHARE to specify the location of the BIOS. The usage of external large BIOS images (up to 512k) at memory top is now supported, but we still recommend to use the BIOS distributed with Bochs. The start address is optional, since it can be calculated from image size.

Example: optromimage1: file=optionalrom.bin, address=0xd0000 This enables Bochs to load up to 4 optional ROM images. Be sure to use a read-only area, typically between C8000 and EFFFF. These optional ROM images should not overwrite the rombios (located at F0000-FFFFF) and the videobios (located at C0000-C7FFF). Those ROM images will be initialized by the BIOS if they contain the right signature (0x55AA). It can also be a convenient way to upload some arbitrary code/data in the simulation, that can be retrieved by the boot loader

Examples: vgaromimage: file=bios/VGABIOS-elpin-2.40 vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest-cirrus This tells Bochs what VGA ROM BIOS to load (at 0xC0000). A VGA BIOS from Elpin Systems, Inc. as well as a free LGPL'd VGA BIOS are provided in the source and binary distributions. Please check with the vga option to decide what VGA BIOS to use.

Examples: vga: extension=cirrus vga: extension=vbe Here you can specify the display extension to be used. With the value 'none' you can use standard VGA with no extension. Other supported values are 'vbe' for Bochs VBE (needs VGABIOS-lgpl-latest as VGA BIOS, see vgaromimage option) and 'cirrus' for Cirrus SVGA support (needs VGABIOS-lgpl-latest-cirrus as VGA BIOS).

Examples: 2.88M 3.5" media: floppya: 2_88=a:, status=inserted 1.44M 3.5" media (write protected): floppya: 1_44=floppya.img, status=inserted, write_protected=1 1.2M 5.25" media: floppyb: 1_2=/dev/fd0, status=inserted 720K 3.5" media: floppya: 720k=/usr/local/bochs/images/win95.img, status=inserted auto-detect floppy media type: floppya: image=floppy.img, status=inserted use directory as VFAT media: floppya: 1_44=vvfat:path, status=inserted 1.44M 3.5" floppy drive, no media: floppya: type=1_44 Floppya is the first drive, and floppyb is the second drive. If you're booting from a floppy, floppya should point to a bootable disk. To read from a disk image, write the name of the image file. In many operating systems Bochs can read directly from a raw floppy drive. For raw disk access, use the device name (Unix systems) or the drive letter and a colon (Windows systems). Following floppy media types are supported: 2_88, 1_44, 1_2, 720k, 360k, 320k, 180k, 160k, as well as "image" to let Bochs auto-detect the type of floppy media (does only work with images, not with raw floppy drives). In that case the size must match one of the supported types. You can set the initial status of the media to ejected or inserted. Usually you will want to use inserted. The parameter 'type' can be used to enable the floppy drive without media and status specified. Usually the drive type is set up based on the media type. The optional parameter 'write_protected' can be used to control the media write protect switch. By default it is turned off.

Examples: ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14 ata1: enabled=1, ioaddr1=0x170, ioaddr2=0x370, irq=15 ata2: enabled=1, ioaddr1=0x1e8, ioaddr2=0x3e0, irq=11 ata3: enabled=1, ioaddr1=0x168, ioaddr2=0x360, irq=9 These options enables up to 4 ata channels. For each channel the two base io addresses and the irq must be specified. ata0 and ata1 are enabled by default, with the values shown above.

Examples: ata0-master: type=disk, path=10M.img, mode=flat, cylinders=306, heads=4, spt=17, translation=none ata1-master: type=disk, path=2GB.cow, mode=vmware3, cylinders=5242, heads=16, spt=50, translation=echs ata1-slave: type=disk, path=3GB.img, mode=sparse, cylinders=6541, heads=16, spt=63, translation=auto ata2-master: type=disk, path=7GB.img, mode=undoable, cylinders=14563, heads=16, spt=63, translation=lba ata2-slave: type=cdrom, path=iso.sample, status=inserted This defines the type and characteristics of all attached ata devices: Option Comments Possible values type type of attached device [disk | cdrom] path path of the image mode image type, only valid for disks [flat | concat | external | dll | sparse | vmware3 | vmware4 | undoable | growing | volatile | vvfat ] cylinders only valid for disks heads only valid for disks spt only valid for disks status only valid for cdroms [inserted | ejected] biosdetect type of biosdetection [none | auto], only for disks on ata0 [cmos] translation type of translation done by the BIOS (legacy int13), only for disks [none | lba | large | rechs | auto] model string returned by identify device ATA command journal optional filename of the redolog for undoable, volatile and vvfat disks You have to tell the type of the attached device. For Bochs 2.0 or later, it can be disk or cdrom. You have to point the "path" at a hard disk image file, cdrom iso file, or physical cdrom device. To create a hard disk image, try running bximage (see ). It will help you choose the size and then suggest a line that works with it. In Unix it is possible to use a raw device as a Bochs hard disk, but we don't recommend it for safety reasons. In Windows, there is no easy way. Disk geometry autodetection works with images created by bximage if CHS is set to 0/0/0 (cylinders are calculated using heads=16 and spt=63). For other hard disk images and modes the cylinders, heads, and spt are mandatory. In all cases the disk size reported from the image must be exactly C*H*S*512. Flat hard disk images from other projects might store additional information at the end of the file that makes this check fail. Only in this case it is safe to select "continue" when Bochs panics. The disk translation scheme (implemented in legacy int13 BIOS functions, and used by older operating systems like MS-DOS), can be defined as: none : no translation, for disks up to 528MB (1032192 sectors) large : a standard bitshift algorithm, for disks up to 4.2GB (8257536 sectors) rechs : a revised bitshift algorithm, using a 15 heads fake physical geometry, for disks up to 7.9GB (15482880 sectors). (don't use this unless you understand what you're doing) lba : a standard lba-assisted algorithm, for disks up to 8.4GB (16450560 sectors) auto : autoselection of best translation scheme. (it should be changed if system does not boot) Please see for a discussion on translation scheme. The mode option defines how the disk image is handled. Disks can be defined as: flat : one file flat layout concat : multiple files layout external : developer's specific, through a C++ class dll : developer's specific, through a DLL sparse : stackable, commitable, rollbackable vmware3 : vmware version 3 disk support vmware4 : vmware version 4 disk support undoable : flat file with commitable redolog growing : growing file volatile : flat file with volatile redolog vvfat: local directory appears as VFAT disk (with volatile redolog / optional commit) Please see for a discussion on disk modes. Default values are: mode=flat, biosdetect=auto, translation=auto, model="Generic 1234" The biosdetect option has currently no effect on the BIOS. Make sure the proper ata option is enabled when using a device on that ata channel.

Examples: boot: floppy boot: cdrom, disk boot: network, disk boot: cdrom, floppy, disk This defines the boot sequence. You can specify up to 3 boot drives, which can be 'floppy', 'disk', 'cdrom' or 'network' (boot ROM). Legacy 'a' and 'c' are also supported.

Example: floppy_bootsig_check: disabled=1 This disables the 0xaa55 signature check on boot floppies The check is enabled by default.

The configuration interface is a series of menus or dialog boxes that allows you to edit all the settings that control Bochs' behavior. Depending on the platform there are up to 3 choices of configuration interface: a text mode version called "textconfig" and two graphical versions called "win32config" and "wx". The text mode version uses stdin/stdout and is always compiled in, unless Bochs is compiled for wx only. The choice "win32config" is only available on win32 and it is the default there. The choice "wx" is only available when Bochs is compiled with wxWidgets support, see . If you do not write a config_interface line, Bochs will choose a default for you (usually textconfig). wxWidgets provides both a configuration interface and a display library. So if you use the "wx" configuration interface, you must also use the "wx" display library, see display_library option. Examples: config_interface: textconfig config_interface: win32config config_interface: wx

The display library is the code that displays the Bochs VGA screen. Bochs has a selection of about 10 different display library implementations for different platforms. If you run configure with multiple --with-* options, the display_library option lets you choose which one you want to run with. If you do not use a display_library line, Bochs will choose a default for you. wxWidgets provides both a configuration interface and a display library. So if you use the "wx" display library, you must also use the "wx" configuration interface, see config_interface option. Examples: display_library: x display_library: sdl Some display libraries now support specific option to control their behaviour. See the examples below for currently supported options. display_library: rfb, options="timeout=60" # time to wait for client display_library: sdl, options="fullscreen" # startup in fullscreen mode display_library: win32, options="gui_debug" # use win32 debugger gui frontend display_library: x, options="hideIPS" # disable IPS output in status bar display_library: x, options="gui_debug" # use GTK debugger gui frontend Option Description x use X windows interface, cross platform win32 use native win32 libraries carbon use Carbon library (for MacOS X) beos use native BeOS libraries macintosh use MacOS pre-10 amigaos use native AmigaOS libraries sdl use SDL library, cross platform, details in svga use SVGALIB library for Linux, allows graphics without X windows term text only, uses curses/ncurses library, cross platform rfb provides an interface to AT&T's VNC viewer, cross platform, details in wx use wxWidgets library, cross platform, details in nogui no display at all

Examples: log: bochsout.txt log: - log: /dev/tty (Unix only) log: /dev/null (Unix only) log: nul (win32 only) Give the path of the log file you'd like Bochs debug and misc. verbiage to be to be written to. If you don't use this option or set the filename to '-' the output is written to the console. If you really don't want it, make it "/dev/null" (Unix) or "nul" (win32). :^(

Examples: logprefix: %t-%e-@%i-%d logprefix: %i%e%d This handles the format of the string prepended to each log line. You may use those special tokens : %t : 11 decimal digits timer tick %i : 8 hexadecimal digits of current cpu eip (ignored in SMP configuration) %e : 1 character event type ('i'nfo, 'd'ebug, 'p'anic, 'e'rror) %d : 5 characters string of the device, between brackets Default is %t%e%d

Examples: debug: action=ignore info: action=report error: action=report panic: action=ask During simulation, Bochs encounters certain events that the user might want to know about. These events are divided into four levels of importance: debug, info, error, and panic. Debug messages are usually only useful when writing Bochs code or when trying to locate a problem. There may be thousands of debug messages per second, so be careful before turning them on. Info messages tell about interesting events that don't happen that frequently. Bochs produces an "error" message when it finds a condition that really shouldn't happen, but doesn't endanger the simulation. An example of an error might be if the emulated software produces an illegal disk command. Panic messages mean that Bochs cannot simulate correctly and should probably shut down. A panic can be a configuration problem (like a misspelled bochsrc line) or an emulation problem (like an unsupported video mode). The debug, info, error, and panic lines in the bochsrc control what Bochs will do when it encounters each type of event. The allowed actions are: fatal (terminate bochs), ask (ask the user what to do), report (print information to the console or log file), or ignore (do nothing). The recommended settings are listed in the sample above. The safest action for panics is "fatal" or "ask". If you are getting lots of panics and get tired of telling it to continue each time, you can try action=report instead. If you allow Bochs to continue after a panic, don't be surprised if you get strange behavior or crashes after a panic occurs. Please report panic messages to the bochs-developers mailing list unless it is just a configuration problem like "could not find hard drive image."

Examples: debugger_log: debugger.out debugger_log: /dev/null (Unix only) debugger_log: - Give the path of the log file you'd like Bochs to log debugger output. If you really don't want it, make it '/dev/null', or '-'.

Examples: com1: enabled=1, mode=null com1: enabled=1, mode=mouse com1: enabled=1, mode=term, dev=/dev/ttyp9 com2: enabled=1, mode=file, dev=serial.out com3: enabled=1, mode=raw, dev=com1 com3: enabled=1, mode=socket-client, dev=localhost:8888 com3: enabled=1, mode=socket-server, dev=localhost:8888 com4: enabled=1, mode=pipe-client, dev=\\.\pipe\mypipe com4: enabled=1, mode=pipe-server, dev=\\.\pipe\mypipe This defines a serial port (UART type 16550A). When using the mode 'term', you can specify a device to use as com1. This can be a real serial line, or a pty. To use a pty (under X/Unix), create two windows (xterms, usually). One of them will run Bochs, and the other will act as com1. Find out the tty of the com1 window using the `tty' command, and use that as the `dev' parameter. Then do `sleep 1000000' in the com1 window to keep the shell from messing with things, and run Bochs in the other window. Serial I/O to com1 (port 0x3f8) will all go to the other window. When using socket* and pipe* (win32 only) modes Bochs becomes either socket/named pipe client or server. In client mode it connects to an already running server (if connection fails Bochs treats com port as not connected). In server mode it opens socket/named pipe and waits until a client application connects to it before starting simulation. This mode is useful for remote debugging (e.g. with gdb's "target remote host:port" command or windbg's command line option -k com:pipe,port=\\.\pipe\pipename). Note: 'socket' is a shorthand for 'socket-client', 'pipe' for 'pipe-client'. Socket modes use simple TCP communication, pipe modes use duplex byte mode pipes. Other serial modes are 'null' (no input/output), 'file' (output to a file specified as the 'dev' parameter), 'raw' (use the real serial port - under construction for win32), 'mouse' (standard serial mouse - requires mouse option setting 'type=serial' or 'type=serial_wheel').

Examples: parport1: enabled=1, file="parport.out" parport2: enabled=1, file="/dev/lp0" parport1: enabled=0 This defines a parallel (printer) port. When turned on and an output file is defined, the emulated printer port sends characters printed by the guest OS into the output file. On some platforms, a device filename can be used to send the data to the real parallel port (e.g. "/dev/lp0" on Linux, "lpt1" on win32 platforms).

Example: sb16: midimode=1, midi=/dev/midi00, wavemode=1, wave=/dev/dsp, loglevel=2, log=sb16.log, dmatimer=600000 The example is wrapped onto several lines for formatting reasons, but it should all be on one line in the actual bochsrc file. This defines the Sound Blaster 16 emulation, see for more information. It can have several of the following properties. All properties are in the usual "property=value" format. midi: The filename is where the midi data is sent to. This can be a device or just a file if you want to record the midi data. On a Windows host this parameter is ignored when using output to the sound device. On a Linux host with ALSA present and this parameter starting with "alsa:", the default sequencer device will be used with the given client and port parameters instead of an OSS device. midimode: 0 = No data should be output. 1 = output to device (system dependent - midi denotes the device driver). 2 = SMF file output, including headers. 3 = Output the midi data stream to the file (no midi headers and no delta times, just command and data bytes). wave: This is the device/file where wave output is stored. On a Windows host this parameter is ignored when using output to the sound device. On a Linux host with ALSA present and this parameter set to "alsa", the default PCM output device will be used instead of an OSS device. wavemode: 0 = no data 1 = output to device (system dependent - wave denotes the device driver). 2 = VOC file output, including headers. 3 = Output the raw wave stream to the file. log: The file to write the sb16 emulator messages to. loglevel: 0 = No log. 1 = Resource changes, midi program and bank changes. 2 = Severe errors. 3 = All errors. 4 = All errors plus all port accesses. 5 = All errors and port accesses plus a lot of extra information. It is possible to change the loglevel at runtime. dmatimer: Microseconds per second for a DMA cycle. Make it smaller to fix non-continuous sound. 750000 is usually a good value. This needs a reasonably correct setting for the ips parameter of the cpu option. It is possible to adjust the dmatimer value at runtime.

Examples: es1370: enabled=1, wavedev="" # win32 es1370: enabled=1, wavedev=alsa # Linux with ALSA This defines the ES1370 sound emulation. The parameter 'enabled' controls the presence of the device. In addition to this, it must be assigned to a PCI slot. The 'wavedev' parameter is similar to the 'wave' parameter of the SB16 soundcard. Currently only the output of the DAC2 is sent to the wave device.

Examples: vga_update_interval: 50000 # default vga_update_interval: 250000 Video memory is scanned for updates and screen updated every so many virtual microseconds. Keep in mind that you must tweak the ips parameter of the cpu option to be as close to the number of emulated instructions-per-second your workstation can do, for this to be accurate.

Example: keyboard_serial_delay: 250 # default Approximate time in microseconds that it takes one character to be transferred from the keyboard to controller over the serial path.

Example: keyboard_paste_delay: 100000 # default Approximate time in microseconds between attempts to paste characters to the keyboard controller. This leaves time for the guest os to deal with the flow of characters. The ideal setting depends on how your operating system processes characters. The default of 100000 usec (.1 seconds) was chosen because it works consistently in Windows.

This defines the parameters of the clock inside Bochs: sync This defines the method how to synchronize the Bochs internal time with realtime. With the value 'none' the Bochs time relies on the IPS value and no host time synchronization is used. The 'slowdown' method sacrifices performance to preserve reproducibility while allowing host time correlation. The 'realtime' method sacrifices reproducibility to preserve performance and host-time correlation. It is possible to enable both synchronization methods. time0 Specifies the start (boot) time of the virtual machine. Use a time value as returned by the time(2) system call. If no time0 value is set or if time0 equal to 1 (special case) or if time0 equal 'local', the simulation will be started at the current local host time. If time0 equal to 2 (special case) or if time0 equal 'utc', the simulation will be started at the current utc time. Syntax: clock: sync=[none|slowdown|realtime|both], time0=[timeValue|local|utc] Examples: clock: sync=none, time0=local # Now (localtime) clock: sync=slowdown, time0=315529200 # Tue Jan 1 00:00:00 1980 clock: sync=none, time0=631148400 # Mon Jan 1 00:00:00 1990 clock: sync=realtime, time0=938581955 # Wed Sep 29 07:12:35 1999 clock: sync=realtime, time0=946681200 # Sat Jan 1 00:00:00 2000 clock: sync=none, time0=1 # Now (localtime) clock: sync=none, time0=utc # Now (utc/gmt) Default value are sync=none, time0=local

Examples: mouse: enabled=1 mouse: type=imps2, enabled=1 mouse: type=serial, enabled=1 mouse: enabled=0, toggle=ctrl+f10 This defines parameters for the emulated mouse type, the initial status of the mouse capture and the runtime method to toggle it. type With the mouse type option you can select the type of mouse to emulate. The default value is 'ps2'. The other choices are 'imps2' (wheel mouse on PS/2), 'serial', 'serial_wheel' and 'serial_msys' (one com port requires setting 'mode=mouse', see com option). To connect a mouse to an USB port, see the usb_uhci or 'usb_ohci' option (requires PCI and USB support). enabled The Bochs gui creates mouse "events" unless the 'enabled' option is set to 0. The hardware emulation itself is not disabled by this. Unless you have a particular reason for enabling the mouse by default, it is recommended that you leave it off. You can also toggle the mouse usage at runtime (see headerbar and the 'toggle' option below). toggle The default method to toggle the mouse capture at runtime is to press the CTRL key and the middle mouse button ('ctrl+mbutton'). This option allows to change the method to 'ctrl+f10' (like DOSBox) or 'ctrl+alt' (like QEMU) or 'f12' (replaces win32 'legacyF12' option).

Example: private_colormap: enabled=1 Requests that the GUI creates and uses its own non-shared colormap. This colormap will be used when in the Bochs window. If not enabled, a shared colormap scheme may be used. Once again, enabled=1 turns on this feature and 0 turns it off.

Examples: i440fxsupport: enabled=1 # default if compiled with PCI support i440fxsupport: enabled=1, slot1=pcivga, slot2=ne2k This option controls the presence of the i440FX PCI chipset. You can also specify the devices connected to PCI slots. Up to 5 slots are available. These devices are currently supported: cirrus, es1370, ne2k, pcivga, pcidev, pcipnic and usb_ohci.

Example: pcidev: vendor=0xbabe, device=0x2bad Enables the mapping of a host PCI hardware device within the virtual PCI subsystem of the Bochs x86 emulator. The arguments vendor and device should contain the PCI vendor ID respectively the PCI device ID of the host PCI device you want to map within Bochs. The PCI device mapping is still in a very early stage of development and thus it is very experimental. This feature requires Linux as a host operating system. Besides the pcidev config line you will need to load a pcidev kernel module within your Linux host OS. This kernel module is located in the bochs/host/linux/pcidev/ directory.

Examples: usb_uhci: enabled=1, port1=mouse, port2=disk:usbstick.img usb_uhci: enabled=1, port1=hub:7, port2=disk:growing:usbdisk.img usb_uhci: enabled=1, port2=disk:undoable:usbdisk.img, options1=journal:redo.log usb_uhci: enabled=1, port1=printer:printdata.bin, port2=cdrom:image.iso This option controls the presence of the USB root hub which is a part of the i440FX PCI chipset. With the portX option you can connect devices to the hub (currently supported: 'mouse', 'tablet', 'keypad', 'disk', 'cdrom', 'hub' and 'printer'). The optionsX parameter can be used to assign specific options to the device connected to the corresponding USB port. Currently this feature is only used to set the speed reported by device and by the 'disk' device to specify an alternative redolog file of some image modes. If you connect the mouse or tablet to one of the ports, Bochs forwards the mouse movement data to the USB device instead of the selected mouse type. When connecting the keypad to one of the ports, Bochs forwards the input of the numeric keypad to the USB device instead of the PS/2 keyboard. To connect a 'flat' mode image as an USB hardisk you can use the 'disk' device with the path to the image separated with a colon. To use other disk image modes similar to ATA disks the syntax 'disk:mode:filename' must be used (see above). To emulate an USB cdrom you can use the 'cdrom' device name and the path to an ISO image or raw device name also separated with a colon. An option to insert/eject media is available in the runtime configuration. The device name 'hub' connects an external hub with max. 8 ports (default: 4) to the root hub. To specify the number of ports you have to add the value separated with a colon. Connecting devices to the external hub ports is only available in the runtime configuration. The device 'printer' emulates the HP Deskjet 920C printer. The PCL data is sent to a file specified in bochsrc.txt. The current code appends the PCL code to the file if the file already existed. It would probably be nice to overwrite the file instead, asking user first. PCI support must be enabled.

Example: usb_ohci: enabled=1 This option controls the presence of the USB OHCI host controller with a 2-port hub. The portX option accepts the same device types with the same syntax as the UHCI controller (see the usb_uhci option). The OHCI HC must be assigned to a PCI slot.

Example: gdbstub: enabled=1, port=1234, text_base=0, data_base=0, bss_base=0 Default: gdbstub: enabled=0 This enables the GDB stub. See .

The ne2k line configures an emulated NE2000-compatible Ethernet adapter, which allows the guest machine to communicate on the network. To disable the NE2000 just comment out the ne2k line. Examples: ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=xl0 ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=en0 #macosx ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0 ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=win32, ethdev=MYCARD ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=vde, ethdev="/tmp/vde.ctl" ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=vnet, ethdev="c:/temp" ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tap, ethdev=tap0 ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tuntap, ethdev=/dev/net/tun0, script=./tunconfig ne2k: mac=fe:fd:00:00:00:01, ethmod=slirp, script=/usr/local/bin/slirp ioaddr, irq: You probably won't need to change ioaddr and irq, unless there are IRQ conflicts. These parameters are ignored if the NE2000 is assigned to a PCI slot. mac: The MAC address MUST NOT match the address of any machine on the net. Also, the first byte must be an even number (bit 0 set means a multicast address), and you cannot use ff:ff:ff:ff:ff:ff because that's the broadcast address. For the ethertap module, you must use fe:fd:00:00:00:01. There may be other restrictions too. To be safe, just use the b0:c4... address. ethmod: The ethmod value defines which low level OS specific module to be used to access physical ethernet interface. You can also specify a network simulator or a module with no input/output ("null"). See the table below for currently supported values. ethdev: The ethdev value is the name of the network interface on your host platform. On UNIX machines, you can get the name by running ifconfig. On Windows machines, you must run niclist to get the name of the ethdev. Niclist source code is in misc/niclist.c and it is included in Windows binary releases. script: The script value is optional, and is the name of a script that is executed after bochs initialize the network interface. You can use this script to configure this network interface, or enable masquerading. This is mainly useful for the tun/tap devices that only exist during Bochs execution. The network interface name is supplied to the script as first parameter The following table shows the available ethernet modules with description, whether the "ethdev" and "script" parameters are used or not and the Bochs version where this module was added. Module Description ethdev script Bochs version arpback ARP simulator - disabled by default. No No 1.3 fbsd FreeBSD / OpenBSD packetmover. Yes No 1.0 linux Linux packetmover - 'root' privileges required, no connection to the host machine. Yes No 1.3 null Null packetmover. All packets are discarded, but logged to a few files. No No 1.0 tap TAP packetmover. Yes Yes 1.4 tuntap TUN/TAP packetmover - see Configuring and using a tuntap network interface. Yes Yes 2.0 vde Virtual Distributed Ethernet packetmover. Yes Yes 2.2 vnet ARP, ping (ICMP-echo), DHCP and read/write TFTP simulation. The virtual host uses 192.168.10.1. DHCP assigns 192.168.10.2 to the guest. The TFTP server uses the ethdev value for the root directory and doesn't overwrite files. Yes, for TFTP No 2.2 slirp Ethernet backend for Slirp and a builtin DHCP server. Adds user mode networking to Bochs using Slirp. Only tested with the most recent Slirp version with Debian patches applied. The fullbolt Slirp version should be used. The "script" parameter should point to the Slirp binary. No Yes 2.2 win32 Win32 packetmover - WinPCap driver required. Yes No 1.3

Example: pnic: enabled=1, mac=b0:c4:20:00:00:00, ethmod=vnet To support the Bochs/Etherboot pseudo-NIC, Bochs must be compiled with the --enable-pnic configure option. It accepts the same syntax (for mac, ethmod, ethdev, script) and supports the same networking modules as the NE2000 adapter. In addition to this, it must be assigned to a PCI slot.

Examples: keyboard_mapping: enabled=0, map= keyboard_mapping: enabled=1, map=gui/keymaps/x11-pc-de.map This enables a remap of a physical localized keyboard to a virtualized U.S. keyboard, as the PC architecture expects. If enabled, the keymap file must be specified. Keyboard mapping is available for X windows, SDL (Linux port) and wxWidgets (GTK port). For SDL you have to use keymaps designed for SDL, the wxWidgets GUI uses the keymaps for X windows.

Examples: keyboard_type: xt keyboard_type: at keyboard_type: mf Type of keyboard returned by a "identify keyboard" command to the keyboard controller. It must be one of "xt", "at" or "mf". Defaults to "mf". It should be ok for almost everybody. A known exception is French macs, that do have a "at"-like keyboard.

Examples: user_shortcut: keys=ctrl-alt-del user_shortcut: keys=ctrl-alt-esc This defines the keyboard shortcut to be sent when you press the "user" button in the headerbar. The shortcut string is a combination of maximum 3 key names (listed below) separated with a '-' character. Valid key names: "alt", "bksl", "bksp", "ctrl", "del", "down", "end", "enter", "esc", "f1", ... "f12", "home", "ins", "left", "menu", "minus", "pgdwn", "pgup", "plus", "right", "shift", "space", "tab", "up", "win", "print" and "power".

Example: cmosimage: file=cmos.img, rtc_init=time0 This defines image file that can be loaded into the CMOS RAM at startup. The rtc_init parameter controls whether initialize the RTC with values stored in the image. By default the time0 argument given to the clock option is used. With 'rtc_init=image' the image is the source for the initial time.

Example: plugin_ctrl: biosdev=0, speaker=0 Controls the presence of optional plugins without a separate option. By default all existing plugins are enabled. These plugins are currently supported: 'acpi', 'biosdev', 'extfpuirq', 'gameport', 'iodebug', 'pci_ide', 'speaker' and 'unmapped'.

Example: user_plugin: name=testdev Load user-defined plugin. This option is available only if Bochs is compiled with plugin support. Maximum 8 different plugins are supported. See the example in the Bochs sources how to write a plugin device.

Example: magic_break: enabled=1 This enables the "magic breakpoint" feature when using the debugger. The useless cpu instruction XCHG BX, BX causes Bochs to enter the debugger mode. This might be useful for software development.

Example: port_e9_hack: enabled=1 The 0xE9 port doesn't exists in normal ISA architecture. However, we define a convention here, to display on the console of the system running Bochs anything that is written to it. The idea is to provide debug output very early when writing BIOS or OS code for example, without having to bother with setting up a serial port or etc. Reading from port 0xE9 will will return 0xe9 to let you know if the feature is available. Leave this 0 unless you have a reason to use it.

Example: debug_symbols: file=mysymbols.sym debug_symbols: file=mysymbols.sym, offset=0x1000 This loads symbols from the specified file for use in Bochs' internal debugger. Symbols are loaded into global context. This is equivalent to issuing ldsym debugger command at start up.

This section is a detailed description for configuring Sound Blaster 16 from source. If you have a binary and all you want to know is what to put in your bochsrc file, see sb16 option. The original version of the Sound Blaster 16 (SB16) emulation for Bochs was written and donated by Josef Drexler. The entire set of his SB16 patches have been integrated into Bochs, however, so you can find everything you need here.

Right now, MPU401 emulation is next to perfect. It supports UART and SBMIDI mode, because the SB16's MPU401 ports can't do anything else as well. The digital audio basically works, but the emulation is too slow for fluent output unless the application doesn't do much in the background (or the foreground, really). The sound tends to looping or crackle on slower computer, but the emulation appears to be correct. Even a MOD player works, although only for lower sampling speeds. Also, the MIDI data running through the MPU401 ports can be written into a SMF, that is the standard midi file. The wave output can be written into a VOC file, which has a format defined by Creative Labs. This file format can be converted to WAV by sox for example.

Output is supported on Windows, Linux, FreeBSD, MacOS 9 and MacOSX at the moment. On Linux, the output goes to any file or device. If you have a wavetable synthesizer, midi can go to /dev/midi00, otherwise you may need a midi interpreter. For example, the midid program from the DosEmu project would work. Wave output should go to /dev/dsp. These devices are assumed to be OSS devices, if they're not some of the ioctl's might fail. If ALSA is present on Linux and the wave device is set to alsa, Bochs uses it's default PCM output device instead of an OSS device. On Windows, midi and (wave) output go to the midi mapper and the wave mapper, respectively. A future version might have selectable output devices.

A wavetable synthesizer on /dev/midi00 and a working /dev/dsp if you want real time music and sound, otherwise output to midi and wave files is also possible. Optionally, you can use a software midi interpreter, such as the midid program from the DosEmu project instead of /dev/midi00.

You need to configure Bochs using the --enable-sb16 option. There are a few values in config.h that are relevant to the sound functions. Edit config.h after running configure, but before compiling. BX_USE_SB16_SMF should be 1 unless you intend to have several sound cards running at the same time. BX_SOUND_OUTPUT_C is the name of the class used for output. The default is to have no output functions, so you need to change this if you want any sound. The following are supported at the moment: bx_sound_linux_c for output to /dev/dsp and /dev/midi00 on Linux, FreeBSD and maybe other OSes that use the OSS driver. bx_sound_windows_c for output to the midi and wave mapper of Windows 3.1 and higher. bx_sound_output_c for no output at all. Setup the SB16 emulation in your bochsrc, according to instructions in that file (see sb16 option).

The source for the SB16CTRL program that is used to modify the runtime behavior of the SB16 emulation is included in misc/sb16/. It is a C program that can be run from inside the emulation. It currently supports the following commands: Option Description -i number Show the selected emulator info string, e.g. sb16ctrl -i 3 to show how many patch translations are active. -t six numbers Load a translation into the translation table. The numbers are: "OldBankMSB,OldBankLSB,OldProgram,NewBankMSB,NewBankLSB,NewProgram". All values can be 0..127 or 255. 255 for "Old" values means match any and for "New" values means don't change, e.g. sb16ctrl -t 255,255,0,255,255,32 to change patch 0 (Piano) to patch 32 (Acoustic Bass). -r Reset the patch translation table e.g. sb16ctrl -r. -m some numbers Upload the given numbers to the midi output device. Note that it should be a complete midi message, and also that it is subject to patch translation, e.g. sb16ctrl -m 0x80,64,0 to send a note-off message to channel 0. -f filename Read in a file and execute the commands in it. These have the same format as the above commands, except that they don't have the dash "-" in front of them. Comment lines are supported and start with a hash sign "#". -h Show a brief summary of the commands. All numbers can be valid parameters to the strtol() function, so hex and octal notation is fine. They have to be delimited by either commas "," or slashes "/", spaces are not allowed. The command line can have any number of commands. However, if none are given, "-f -" is assumed, which means commands are taken from stdin.

Port it to more OS's. Finish the OPL3 FM emulation by translating the music to midi data.

You can find a description of the sound output classes and more details on Sound Blaster 16 emulation in the developer documentation.

Christophe Bothamy wrote the keymapping code for Bochs, and provided this documentation for how to create new keymaps. Keymapping was first implemented for X windows only, so there are many references to X-specific values in this section. In Bochs 2.0 keymapping is also available for SDL (Linux port) and wxWidgets (wxGTK port). The standard US Keyboard looks like this: ------------------------------------------- Top row Esc F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 ------------------------------------------- 2nd row ` 1 2 3 4 5 6 7 8 9 0 - = \ Back ------------------------------------------- 3rd row Tab Q W E R T Y U I O P [ ] Enter ------------------------------------------- 4rd row Caps A S D F G H J K L ; ' ------------------------------------------- 5rd row lShift l\ Z X C V B N M , . / rShift ------------------------------------------- 6rd row lCtrl lAlt Space rAlt rCtrl ------------------------------------------- Each key of the US keyboard maps to a Bochs constant named BX_KEY_symbol. You can find the current list of BX_KEY_symbol in the BX_KEY table, below. Please note that there is only one BX_KEY_symbol for each physical key. Now, for each key of the US keyboard, look at which symbols you can type on your real keyboard. Each symbol maps to a X-windows XK_symbol constant. In X11/keysymdef.h, you will find the list of all possible XK_symbol on your system. Alternatively, you can use a small utility called "xev" that prints out the symbol names of a pressed key. Note that the symbol name given by xev does not contain the XK_ prefix. Don't forget to add a line for every symbol you can type on each key. For the key BX_KEY_A, you can type both lowercase 'a' and uppercase 'A', so you would need two different entries. You can then create your own map file. Keymap files are found in the "gui/keymaps" directory in the source code, or in the "keymaps" directory in binary releases. Look at the existing keymap file as an example, and create a file containing one line for each symbol. The first column tells what key or combination of keys can be used to produce a given symbol. The second column is the ASCII equivalent for that symbol, or a special keyword (none, space, return, tab, backslash, or apostrophe). The third column is the X windows keysym for that symbol. For example : BX_KEY_0 '0' XK_0 BX_KEY_1 '1' XK_1 BX_KEY_2 '2' XK_2 BX_KEY_0+BX_KEY_SHIFT_L ')' XK_parenright BX_KEY_1+BX_KEY_SHIFT_L '!' XK_exclam BX_KEY_2+BX_KEY_SHIFT_L '@' XK_at BX_KEY_A 'a' XK_a BX_KEY_B 'b' XK_b BX_KEY_A+BX_KEY_SHIFT_L 'A' XK_A BX_KEY_B+BX_KEY_SHIFT_L 'B' XK_B BX_KEY_TAB tab XK_Tab BX_KEY_ENTER return XK_Return BX_KEY_F1 none XK_F1 BX_KEY_F2 none XK_F2 BX_KEY_F3 none XK_F3 Now that there are several keymap files in the Bochs distribution, it is easiest to copy an existing keymap and follow the examples you see. When it works, be sure to send it to the mailing list or post it on Source Forge so that we can include it in the next release. You may need to look up some of your country specific X11 symbols in X11/keysymdef.h. BX_KEY constant Keyboard Symbol BX_KEY_CTRL_L left Ctrl BX_KEY_SHIFT_L left Shift BX_KEY_F1 F1 BX_KEY_F2 F2 BX_KEY_F3 F3 BX_KEY_F4 F4 BX_KEY_F5 F5 BX_KEY_F6 F6 BX_KEY_F7 F7 BX_KEY_F8 F8 BX_KEY_F9 F9 BX_KEY_F10 F10 BX_KEY_F11 F11 BX_KEY_F12 F12 BX_KEY_CTRL_R right Ctrl BX_KEY_SHIFT_R right Shift BX_KEY_CAPS_LOCK CapsLock BX_KEY_NUM_LOCK NumLock BX_KEY_ALT_L left Alt BX_KEY_ALT_R right Alt BX_KEY_A A BX_KEY_B B BX_KEY_C C BX_KEY_D D BX_KEY_E E BX_KEY_F F BX_KEY_G G BX_KEY_H H BX_KEY_I I BX_KEY_J J BX_KEY_K K BX_KEY_L L BX_KEY_M M BX_KEY_N N BX_KEY_O O BX_KEY_P P BX_KEY_Q Q BX_KEY_R R BX_KEY_S S BX_KEY_T T BX_KEY_U U BX_KEY_V V BX_KEY_W W BX_KEY_X X BX_KEY_Y Y BX_KEY_Z Z BX_KEY_0 0 BX_KEY_1 1 BX_KEY_2 2 BX_KEY_3 3 BX_KEY_4 4 BX_KEY_5 5 BX_KEY_6 6 BX_KEY_7 7 BX_KEY_8 8 BX_KEY_9 9 BX_KEY_ESC Esc BX_KEY_SPACE SpaceBar BX_KEY_SINGLE_QUOTE ' BX_KEY_COMMA , BX_KEY_PERIOD . BX_KEY_SLASH / BX_KEY_SEMICOLON ; BX_KEY_EQUALS = BX_KEY_LEFT_BRACKET [ BX_KEY_BACKSLASH \ BX_KEY_RIGHT_BRACKET ] BX_KEY_MINUS - BX_KEY_GRAVE ` BX_KEY_BACKSPACE BackSpace BX_KEY_ENTER Enter BX_KEY_TAB Tab BX_KEY_LEFT_BACKSLASH left \ BX_KEY_PRINT PrintScreen BX_KEY_SCRL_LOCK ScrollLock BX_KEY_PAUSE Pause BX_KEY_INSERT Ins BX_KEY_DELETE Del BX_KEY_HOME Home BX_KEY_END End BX_KEY_PAGE_UP PageUo BX_KEY_PAGE_DOWN PageDown BX_KEY_KP_ADD Numeric Keypad + BX_KEY_KP_SUBTRACT Numeric Keypad - BX_KEY_KP_END Numeric Keypad 1 BX_KEY_KP_DOWN Numeric Keypad 2 BX_KEY_KP_PAGE_DOWN Numeric Keypad 3 BX_KEY_KP_LEFT Numeric Keypad 4 BX_KEY_KP_5 Numeric Keypad 5 BX_KEY_KP_RIGHT Numeric Keypad 6 BX_KEY_KP_HOME Numeric Keypad 7 BX_KEY_KP_UP Numeric Keypad 8 BX_KEY_KP_PAGE_UP Numeric Keypad 9 BX_KEY_KP_INSERT Numeric Keypad 0 BX_KEY_KP_DELETE Numeric Keypad . BX_KEY_KP_ENTER Numeric Keypad Enter BX_KEY_KP_MULTIPLY Numeric Keypad * BX_KEY_KP_DIVIDE Numeric Keypad / BX_KEY_UP UpArrow BX_KEY_DOWN DownArrow BX_KEY_LEFT LeftArrow BX_KEY_RIGHT RightArrow BX_KEY_WIN_L Left Windows BX_KEY_WIN_R Right Windows BX_KEY_MENU Menu BX_KEY_ALT_SYSREQ Alt-Sysreq BX_KEY_CTRL_BREAK Ctrl-Break BX_KEY_INT_BACK Internet - back BX_KEY_INT_FORWARD Internet - forward BX_KEY_INT_STOP Internet - stop BX_KEY_INT_MAIL Internet - mail BX_KEY_INT_SEARCH Internet - search BX_KEY_INT_FAVInternet - favoritesBX_KEY_INT_HOME Internet - home BX_KEY_POWER_MYCOMP Powerkeys - my computer BX_KEY_POWER_CALC Powerkeys - calculator BX_KEY_POWER_SLEEP Powerkeys - sleep BX_KEY_POWER_POWER Powerkeys - power BX_KEY_POWER_WAKE Powerkeys - wake

&FIXME; - using plugins? - Resources for users testing status page: tells what has been tried and who got it working search on bochs web site SourceForge - look for bug reports - how to report problems (present as FIXME request in chapter 6 as well) - How to make feature requests?

The following table shows the arguments that can be used on the command line. For other arguments, see section bochsrc. Argument Description -q quick start (skip configuration interface) -f filename specify configuration file -log filename specify Bochs log file -dbglog filename specify Bochs internal debugger log file -n don't try to load a configuration file -r path specify path for restoring state --help display help message and exit These arguments are handled directly after starting Bochs. The next step is to load a default or specified configuration file (unless disabled with -n). Then the rest of the command line (bochsrc options) is parsed. This is done after reading the configuration file so that the command line arguments can override the settings from the file.

If no configuration file is specified on the command line and config file loading is not disabled, Bochs searches for a default configuration file. This is the search order: .bochsrc in the current directory bochsrc in the current directory bochsrc.txt in the current directory (win32 only) bochsrc.bxrc in the current directory (Unix only) .bochsrc in the user's home directory (Unix only) bochsrc in the /etc directory

The configuration interface 'textconfig' is the text mode version of the Bochs configuration system. It is a series of menus (using stdin/stdout) that allows you to edit all the settings that control Bochs' behavior. If you do not write a config_interface line, Bochs will choose it as the default for you (unless Bochs is compiled for Win32 or wxWidgets only). It consists of these three parts: the start menu the headerbar buttons the runtime configuration

If you start Bochs without the quickstart argument (-q), the Bochs configuration main menu appears: ------------------------------ Bochs Configuration: Main Menu ------------------------------ This is the Bochs Configuration Interface, where you can describe the machine that you want to simulate. Bochs has already searched for a configuration file (typically called bochsrc.txt) and loaded it if it could be found. When you are satisfied with the configuration, go ahead and start the simulation. You can also start bochs with the -q option to skip these menus. 1. Restore factory default configuration 2. Read options from... 3. Edit options 4. Save options to... 5. Restore the Bochs state from... 6. Begin simulation 7. Quit now Please choose one: [5] Here you can load, edit and save the configuration and finally start the simulation. It is possible to start Bochs without a config file and to edit all the settings using the item "Edit options". Don't forget to save the configuration if you want to use this setup for another Bochs session.

The headerbar appears on top of the Bochs simulation window. Here you can control the behavoiur of Bochs at runtime if you click on one of these buttons: floppy buttons Here you can toggle the status of the floppy media (inserted/ejected). Bochs for win32 presents you a small dialog box for changing the floppy image. You can setup floppy drives using floppya/floppyb option. cdrom button Here you can toggle the status of the cdrom media (inserted/ejected). CD-ROM drives can be set up using ata(0-3)-master/-slave option. On some platforms this button brings a up a small dialog box for changing the CD-ROM image. mouse button Here you can enable the creation of mouse events by the host. Once mouse events are captured, you cannot reach the button anymore, in order to disable capturing again. By default you can enable and disable the mouse capture pressing the CTRL key and the third (middle) mouse button. See the mouse option parameter 'toggle' for other methods to toggle the mouse capture. &FIXME; Support for 2 button mouse to toggle the capture mode not yet complete. Some display libraries still don't support changing the mouse capture at runtime, but it is already supported on RFB, SDL, Win32, wxWidgets and X11. user button Press this button if you want to send the keyboard shortcut defined with the user_shortcut option to the guest. Depending on the used display_library option, it may even be possible to edit the shortcut before sending it. copy button The text mode screen text can be exported to the clipboard after pressing this button. The button has no effect in graphics mode. paste button Text in the clipboard can also be pasted, through Bochs, to the guest OS, as simulated keystrokes. Keyboard mapping must be enabled to make this feature work. snapshot button Press this button if you want to save a snapshot of the text mode screen. Bochs for win32 presents you a "Save as..." dialog box. All other platforms are using the fixed filename "snapshot.txt". config button This button stops the Bochs simulation and starts the runtime configuration. (see below). reset button Press this button to trigger a hardware reset. suspend button Press this button to save current simulation state to a disk. The simulation could be restored back using bochs -r command. For more details read "Save and restore simulation" section of the user manual. power button This button stops the simulation and quits bochs. Some of this features may not be implemented or work different on your host platform.

If you want to change certain settings at runtime, you have to press the "config" button in the headerbar. The simulation stops and the runtime menu appears on the console window / xterm. --------------------- Bochs Runtime Options --------------------- 1. Floppy disk 0: /dev/fd0, size=1.44M, inserted 2. Floppy disk 1: floppyb.img, size=1.44M, inserted 3. 1st CDROM: (master on ata1) /dev/cdrom, ejected 4. 2nd CDROM: (slave on ata1) /dev/cdrecorder, ejected 5. 3rd CDROM: (not present) 6. 4th CDROM: (not present) 7. (not implemented) 8. Log options for all devices 9. Log options for individual devices 10. Instruction tracing: off (doesn't exist yet) 11. USB runtime options 12. Misc runtime options 13. Continue simulation 14. Quit now Please choose one: [15] In the runtime configuration you can change the floppy/cdrom image or device, change the log options or adjust some other settings. If you have trouble with a specific device, you can change the log options for this device only to get more information (e.g. report debug messages). This cannot be done in the configuration file yet.

Starting with version 2.3, Bochs has limited save/restore support. The state of cpu(s), memory and all devices can be saved now. When running Bochs with there will be a button in the header bar called "Suspend". Depending on config interface and gui there will be a prompt where you can enter a path to an existing directory or a gui folder selection dialog box. It is possible to save the state at any time, but we recommend to do it when the simulation is idle. After pressing OK/Enter, Bochs will save a set of files into the selected folder. The state of hard disk images is not handled yet, so Bochs will ask you if you want to continue after saving state. We don't recommend to continue unless you are running a read-only guest system (e.g. Live-CD). To restore the saved simulation state you can select the restore function in the text mode start menu or specify the restore path at the command line: bochs -r /path/to/save-restore-data Then Bochs will start up using the saved configuration and log options, restores the state of the hardware and begins the simulation. In the restore mode Bochs will ignore bochsrc options from the command line and does not load a normal config file.

&FIXME; How to report a panic to the bug tracker? Keyboard mapping problems [...]

Bochs does a very good job in emulating an x86 compatible computer, however, it does not (yet) include a full (100%) emulation of every possible instruction, (BIOS) function call or (hardware) device. Thus, in case something unusual happens, either a not-so-common call to some (BIOS) function or device by some software running inside of it, Bochs has two possibilities to react: If the command doesn't look important (mainly happens only to non-implemented functions in the BIOS), a notice is logged to the log file and the emulation continues. If, however, the command looks important, Bochs panics, because the software being emulated might depend on the successful execution of the given instruction or behavior of the device. A panic does not always mean that the software won't run inside of Bochs, as the software might just be probing the computer for the presence of some instruction/device, and in case it is not found, it simply won't be used at all, by the software. You can tell Bochs what to do in case of a panic, by re-configuring the panic option. If you change the action to "ask", Bochs reports what has happened and asks you what to do. The appearance of the "ask" feature depends on the display library used and the platform. Some display libraries don't support it at all. Some of the device names reported in the panic message are abbreviations, since the length of the names is limited to 5 characters. This small list may help you finding out the name of the device that caused the panic. Prefix Description CLVGA Cirrus SVGA EFIRQ External FPU IRQ IOAP I/O APIC KMAP Keyboard mapping P2I PCI-to-ISA bridge PIDE PCI IDE controller PLGIN Plugin interface STIME Slowdown timer UNMP Unmapped I/O handler VTIME Virtual timer

Refer to for information on how to enable or disable the mouse inside of Bochs at run-time. &FIXME; Mouse behavior

If you are using a program written for DOS which seems to use the text-mode but doesn't display the text properly, you can try the other VGA BIOS, either VGABIOS-lgpl-latest or VGABIOS-elpin-2.40, see the vgaromimage option. &NEEDHELP; Maybe it is a bug in the LGPL VGA BIOS, but for now, it seems to work.

The Bochs community uses three mailing lists to communicate, called bochs-developers, bochs-cvs and bochs-announce.

Bochs-developers is the forum for all Bochs discussions and questions. On average, subscribers get between five and ten messages per day. There are about 350 subscribers. If this sounds like too much email, maybe the bochs-announce list is more appropriate for you. Anyone may join the list, unless they abuse it of course. To subscribe, go to the Bochs-Developers Info Page and type your email address and a password into the web form and click Subscribe. In a few minutes you will get a confirmation email. Follow the directions in the email to complete the subscription process. To unsubscribe, go to the same page and type your email address in the blank at the bottom and click on Edit Options. Then type your password and click Unsubscribe. Once you have subscribed, you can write to bochs-developers@lists.sourceforge.net to send a message to everyone on the list. While it's possible to post without being a subscriber, it's not recommended. If you aren't a subscriber, you might miss the response to your question. Archive of bochs-developers messages

Bochs-announce is a moderated, low-traffic list which carries only periodic announcements of Bochs releases and important events. If you have a very important and truly relevant Bochs announcement, you can try posting it to bochs-announce, but the moderator will have to approve it before it will go out. On average, bochs-announce subscribers get one or two messages per month. There are about 75 subscribers. Anyone may join the list. To subscribe, go to the Bochs-Announce Info Page and type your email address and a password into the web form and click Subscribe. In a few minutes you will get a confirmation email. Follow the directions in the email to complete the subscription process. To unsubscribe, go to the same page and type your email address in the blank at the bottom and click on Edit Options. Then type your password and click Unsubscribe. There is no need to subscribe to both lists, because all bochs-announce messages are forwarded to the developers list. If you subscribe to both, you will get 2 copies of every announcement. Archive of bochs-announce messages

This is the cvs commit mailinglist (a unified diff email will be sent whenever someone does a checkin in the bochs cvs repository). Archive of bochs-cvs messages

Here are a few guidelines for use of the Bochs mailing lists: Please check the documentation before asking questions, but on this list you are very UNLIKELY to get flamed and insulted for being a Bochs beginner. Sending commercial promotions to the list probably will get you some angry responses though. If you are having difficulty finding what you are looking for, try doing a search on Google. If you are searching for Bochs options, for example, you can use this syntax in the Google search box: configuration options site:bochs.sourceforge.net For best results, be sure not to put a space between "site:" and "bochs.sourceforge.net". Be sure to look at more than the first item on the search results. If you still cannot find what you are looking for, be sure you are prepared when you post your question, and post in the right forum. Be sure you include important details, such as the operating system and version of your host, and what it is you are trying to do. If you are getting errors or something is not working, summarize what you checked and what you changed. This will help isolate the problem. Bochs is for everyone. If you are an experienced Bochs user or developer and are helping someone else, be considerate of the other person's feelings. We share a common interest, and we need to encourage each other and be supportive. Also, keep in mind that messages are limited to 40K, so if you want to share a large screen shot or disk image, put it on a web or FTP site and tell people how to find it. Patches are usually small enough that they aren't a problem, especially if compressed. Distribution of copyrighted material, or even offers to distribute copyrighted material WILL NOT be tolerated. The Bochs Project does not distribute any software (disk images) in violation of the license agreement, and users who do so will be warned first and then blocked from the list if it happens again. As an open source project, we rely on donated services from Source Forge and other groups, and we can't afford to put them or ourselves at risk of legal action. It is possible to subscribe and unsubscribe by email. If you do this, you must write to bochs-announce-request or bochs-developers-request. Don't forget the "-request" part or your subscribe message will go to 300+ people.

This was contributed by Greg Alexander in October 2001. What you need: An executable version of Bochs. See Downloading Bochs and Compiling Bochs. The bximage program, included with Bochs. A FreeDOS boot disk, or a boot disk from another OS capable of producing DOS partitions (e.g. a Linux install disk). (Optional) mtools, a program for manipulating DOS disks/images.

Option 1: Using the Unix dd utility: You will need to know the geometry of the disk you want to create. You have to compute the disk sector count: Sectors = Cylinders * Heads * SectorsPerTrack Use the dd command to create your file: dd if=/dev/zero of=teaching.img bs=512 count=sectors (replace "sectors" with the number you computed at the previous step). When you'll update your configuration file, please fill in the same cylinders, heads and sector per track values. Option 2: Run bximage to create a disk image file. You will be greeted with the following prompt: ======================================================================== bximage Disk Image Creation Tool for Bochs ======================================================================== Do you want to create a floppy disk image or a hard disk image? Please type hd or fd. [hd] Since we are creating a hard disk image, accept the default of hd by pressing Enter or typing 'hd' and pressing Enter. Next, bximage will ask for the type of hd to create: What kind of image should I create? Please type flat, sparse or growing. [flat] We want to create a simple flat image, so accept the default by pressing Enter. Then, bximage will ask for the size of the disk image you want to create, in Megabytes: Enter the hard disk size in megabytes, between 1 and 32255 [10] Enter the size of the hard disk you want to create, and press Enter. Bochs will give you some information about the image it is creating, and ask you for a filename to use for the file it is creating. I told it to use the default of 10 megabytes, and was given the following information along with the prompt for a filename: [10] 10 I will create a hard disk image with cyl=20 heads=16 sectors per track=63 total sectors=20160 total size=9.84 megabytes What should I name the image? [c.img] At this point, type in the filename you want to use for the image. The default of "c.img" is appropriate if this will be your only hard disk image. After you have typed in the name of the filename you want to use, press Enter. Bximage will tell you it is writing the disk and will display a status bar as you wait. When it is finished, it will give you a final status report and tell you a line that should be added to your bochsrc when you want to use this disk image. I named my 10 Megabyte image "teaching.img" and the output of bximage looked like this: [c.img] teaching.img Writing: [..........] Done. I wrote 10321920 bytes to teaching.img. The following line should appear in your bochsrc: ata0-master: type=disk, path="teaching.img", mode=flat, cylinders=20, heads=16, spt=63 At this point, a file called "teaching.img" was created in my current directory and is ready to be used as an image file for a Bochs session. You may want to name your image teaching_20-16-63.img so that you always know the values to use for CHS.

Option 1: Using FreeDOS (Advantage: Creates a MBR on the partition.) First, you need to edit the bochsrc file that Bochs uses for configuration information (see ). Open bochsrc with a text editor. Remove all lines in the file which start with "ata0-master:". Add the "ata0-master:" line that was displayed when you ran bximage to bochsrc at the same place where you removed the old "ata0-master:" lines from. Also, you need to download or create a FreeDOS (or DOS, or Windows, or Linux) disk image. Modify the "floppya:" line in your bochsrc to point at the downloaded FreeDOS floppy image and change its status to "status=inserted". Save and close your bochsrc. Now run Bochs (see ). Use the standard FreeDOS commands fdisk and format to format your hard drive image. You must make the image bootable to be able to boot without a floppy disk. However, creating a bootable disk image is best done with a boot disk from the OS you intend to install on the image. Option 2: Using mtools (Disadvantage: Cannot create bootable images without a MBR image.) Use a text editor to add the following line to the file ~/.mtoolsrc: drive c: file="path/filename.img" partition=1 Save and close .mtoolsrc. Next, execute the following commands to create a partition table for the drive image: mpartition -I -s spt -t cyl -h heads c: mpartition -cpv -s spt -t cyl -h heads c: For example, for my 10 meg drive, I used: mpartition -I -s 63 -t 20 -h 16 c: mpartition -cpv -s 63 -t 20 -h 16 c: Next, format the partition you just created using the mformat command: mformat c: And you now have a formatted disk image containing a single DOS partition. The mpartition command doesn't handle images larger than 1024 cylinders properly. The partition size reported by fdisk is okay, but mformat reports only 504 MB (tested with mtools 3.9.9).

Mtools is a set of programs that can read, write, and format DOS disk images. There are links to the Mtools main page and a Win32 port of Mtools on the Bochs Links page, under Resources. The mtools web site has a detailed manual. If anyone wants to write instructions specific to Bochs, we can add it right here.

&FIXME; Bochs tools are external tools developed by ..., and useful to copy to / from guest partition from a GNU/Linux host.

Someone on the bochs-developers list mentioned that they use a program called WinImage, from www.winimage.com to read and write disk images (floppy and hard disk). Winimage is a commercial product with a 30-day trial. If anyone wants to write a tutorial, send mail to &devlist; and volunteer.

This section was contributed by Luca Cassioli and Stanislav Shwartsman I eventually found what all of you were looking for for a long time: a freeware, graphical, win32 compatible HardDisk image editor! It can handle a large variety of formats, but the one you need is VMWARE 2.0 PLAIN DISK: you can import/export to/from Bochs images COMPLETE DIRECTORIES! You can find it at http://hp.vector.co.jp/authors/VA013937/editdisk/index_e.html

Ben Lunt wrote a set of utilities for Dos/Win32 to manipulate flat disk images. You can find it at http://www.frontiernet.net/~fys/mtools.htm These utilities includes : BOCHSRC.EXE "Bochs Resource" A utility to create/modify a Bochs resource file. MKDOSFS.EXE "Make DOS FS" A utility to create a FAT disk image of specified size. MCOPYF.EXE "Copy From" A utility to copy an existing file from a FAT disk image to the current directory. MDEL.EXE "Delete file" A utility to delete an existing file from a FAT disk image. MDIREX.EXE "Directory Extended" A utility to view a FAT disk images directory and FAT contents. MGETIMG.EXE "Get Disk Image" A utility to create a disk image from a floppy (multiple formats). MBOOTCD.EXE "Create a CDROM Image with boot options" Create a CDROM image capable of booting with only a ROOT and a single file. MGETCD.EXE "Get Disk Image of Physical CD" A utility to create a disk image from a CD. MCDINFO.EXE "Get CD Info" A utility to the info from a CD. Not much yet, but a little.

One common problem in X windows is that the screen colors can be abnormal if other X programs have already allocated all the colors. If the colors don't look right, try quitting colorful applications such as Netscape, clearing any complex images in the background, etc. so that Bochs has a chance to allocate the colors it needs. If Bochs continues to have problems, or you want Bochs to have perfect colors without having to quit any other application, you can try turning on the private_colormap option in the configuration file. Using a private colormap causes the Bochs window to have its own set of 256 colors to work with. When the cursor is over the Bochs display, Bochs will look correct and other parts of the screen may change to very strange colors. When the cursor goes to any other window, the other windows will look correct and Bochs will have strange colors. A better solution, if your hardware can support it, is to run your X server with 24-bit or 32-bit color.

One thing you may notice is that the screen saver turns on (screen goes blank) very quickly after you have stopped typing. The reason is that Bochs simulates everything as fast as it can. If the CPU is very busy (running instructions nonstop), simulated time goes by slowly. If the CPU is idle (just waiting for you to type, for example), simulated time speeds up dramatically. In any case, if the screen saver blanks out the screen, just press a key (try shift or control) to restore the screen. There are two strategies to fix this problem. One is to increase the ips parameter of the cpu option in your configuration file. This will cause the simulation time to pass more slowly. The other strategy is to enable the experimental realtime PIT, which tries to keep Bochs in sync with real time. See the bochsrc option clock.

This section describes how to access a floppy or hard disk image within Linux using the loop device. Why would you want to do this? Let's say you have made a small Linux disk image for Bochs, and you want to install some more software on it. You have already downloaded the software onto your real system, so now you want to transfer it to the Bochs disk image. A fast way to transfer the files is to mount the disk image using the loop device.

This section was contributed by Volker Ruppert. Today I have made some tests with the loop device, because I want to exchange files with the bochs disk images. This is what I found out: 1. Using Floppy images is easy, because there is no partition table: losetup /dev/loop0 /usr/local/bochs/dlxlinux/floppya.img Now you can use the image like a real floppy: - format : mkfs.minix /dev/loop0 - filesystem check : fsck.minix /dev/loop0 - mount : mount /dev/loop0 -o loop /mnt/floppy Before you want to restart bochs you must do this: losetup -d /dev/loop0 Don't forget to umount before. 2. If you want access to a hard disk image, you have to calculate the size of the first cylinder. This value is the offset argument for losetup. offset = bytes per sector * sectors per cylinder The command for dlxlinux image looks like this: losetup /dev/loop0 /usr/local/bochs/dlxlinux/hd10meg.img -o 8704 For images created by bximage you must use the value 32256. 3. The hard disk image access doesn't work if the image contains more than one partition. 4. I have made this tests with Linux and I don't know how this could be done with other operating systems.

This section was contributed by Alexander Schuch. The following example mounts a Windows 95 hard disk image called Windows 95 B (2031-16-63) into the FreeBSD file system. It is specific to FreeBSD 5.x; for hints on how to do the same task on FreeBSD 4.x, or for more information in general, check the proper section of the FreeBSD handbook: Network, Memory, and File-Backed File Systems. You can use the same procedure for mounting floppy disk images. # mdconfig -a -t vnode -f "Windows 95 B (2031-16-63)" md0 mdconfig returns the device, your file now is accessable from. # mount -t msdosfs /dev/md0s1 /mnt If you already have other md devices configured, you need to substitute md0s1 with, for example, md6s1. Once you are done working with the image, unmount the md device and detach it. # umount /mnt # mdconfig -d -u 0 And again, if there are other md devices configured, use the proper device number. In case you forgot the number, just ask mdconfig, like: # mdconfig -l md7 # mdconfig -d -u 7

Bochs can now simulate an SMP machine when you use "--enable-smp" in the configure command. SMP support was added by Bryce Denney, who was very interested in watching a multiprocessor operating system work at a low level. It should also be helpful to operating system developers who are writing SMP drivers, or just for users who want to test drive an SMP machine to see what it looks like. Starting with Bochs 2.2.6 you can set up the number of processors in the bochsrc. See how to set up the number of processors. It is important to understand that configuring bochs for 4 processors will NOT make your single-threaded applications run faster in general! On the contrary, it has to spend time simulating idle processors as well as the ones doing your task. The point is to simulate an SMP system, not to speed up a uniprocessor application. What was required to make SMP work in Bochs? local APIC on each processor with timer one I/O APIC model implement RDTSC (read time stamp counter) a data structure called the Intel Multiprocessor Configuration must be present in BIOS memory space. An SMP-aware operating system probes BIOS memory to find the structure, which contains information about how many processors, their IDs, interrupt sources, etc. Starting with Bochs 2.2.5 these structures are dynamically created by Bochs. ACPI support is required to boot SMP system in most of modern operating systems. For example WinXP 64 bit require ACPI support even for single processor configuration. What needs to be done to improve SMP support? debugger support is still limited. For example, you can set breakpoints, but you can't specify which processor you want to set the breakpoint for. test on any possible SMP operating systems. Currently success reported for Knoppix 4.0.2, WinNT 4.0 and WinXP SMP. several parts of the APIC model which weren't needed before are not implemented yet. A number of people have suggested using threads to simulate each CPU in a different thread. Then on a real SMP machine, the threads can execute in parallel. This is a great idea, but it's not done at present.

All Bochs binaries come with a working version of DLX Linux. This section describes how to configure networking in Bochs and enable it within DLX Linux. First you must add a ne2k line in your bochsrc file. Then, when you boot the DLX Linux image, you need to type some Linux commands to set up an IP address, a network route, and a name server. When you have an ne2k line in your bochsrc file, Bochs will emulate a network card called an NE2000. Below are some examples of valid ne2k lines for various operating systems. Choose the one that's closest to what you need, add it to your bochsrc file, and edit the values if necessary. # sample for Mac OS X ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=en0 # sample for FreeBSD ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=xl0 # sample for Linux ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0 # sample for Windows ne2k: ioaddr=0x300, irq=9, mac=00:c4:3B:00:C3:00, ethmod=win32, ethdev=NE2000 You see the pattern. Usually you won't need to change the I/O address, IRQ number, or MAC address. The ethmod value depends on your host operating system, and it must be either null, fbsd (for FreeBSD or OpenBSD), linux, or win32. The ethdev setting is the name of the network interface on your system, and is also OS-dependent. On UNIX systems you can get the name of the network interface by running ifconfig. (Don't choose the loopback interface.) On Windows systems, the correct ethdev setting is not always obvious, so we provide a utility called niclist to list the names of network interfaces to use. When you run niclist, it will suggest an ne2k line which is a very good first try. Next, if you are on a UNIX machine you will need to become the root user. Since bochs is sending and receiving raw network packets, you need to be root to use the network device. To allow normal users to do this would be a security problem. Now run Bochs to boot DLX Linux. Press enter a few times to accept the default configuration choices. This tells Bochs read the configuration file and then begin. DLX Linux should boot in the Bochs window, and you should see that Linux detects the NE2000 card. Eventually it gets to a login prompt. ne.c:v1.10 9/23/94 Donald Becker (becker@cesdis.gsfc.nasa.gov) NE*000 ethercard probe at 0x300: b0 c4 20 00 00 00 eth0: NE2000 found at 0x300, using IRQ 9. At the login prompt, type "root" to log in as root. Then type the ifconfig and route commands to set up networking. The exact IP numbers in the example won't work for you; you must choose an IP configuration that is legal on your network. dlx login: root Linux 1.3.89. dlx:~# ifconfig eth0 192.168.0.99 # set bochs IP address dlx:~# route add -net 192.168.0.0 # first 3 numbers match IP dlx:~# route add default gw 192.168.0.1 # your gateway to the net dlx:~# _ The bochs IP address must be an unused IP address on your network. If you duplicate someone else's IP address, your network will become very confused. Finally, the network is ready and you can test it out with ping, telnet, or ftp to various machines by their numerical IP address. Keep in mind that for all UNIX host platforms, Bochs networking cannot talk to the host machine. That means the host machine can't be the gateway either. You need another physical machine on the network that bochs can talk to. On Win32 this restriction does not apply. When you have a working network configuration, you can make DLX Linux recreate the same settings the next time you boot. Just add the ifconfig and route commands to the end of /etc/rc.d/rc.inet1. I won't try to describe how to use the vi editor in this limited amount of space... To configure a name server, set up /etc/resolv.conf with the IP address of your name server as shown. dlx:~# echo 'nameserver 192.168.0.1' > /etc/resolv.conf

If you use linux (optionally FreeBSD and Solaris, not tested), you may want to access the network through a tuntap interface. The main advantage of this interface, is that the guest has access to the host. The guest can even have access to the whole network if the host routes or masquerades the guest requests. No extra IP address is needed, all can be done using private IP addresses. You'll find here instructions to set up Linux/Bochs to provide network access to the guest OS through a tuntap interface and private IP network. We're going to see howto : enable the tuntap interface in the Linux Kernel configure Bochs to use the tuntap interface set up the private network between the host and the guest set up the host to masquerade the guest network accesses

From the tuntap.txt file in the Linux kernel tree : TUN/TAP provides packet reception and transmission for user space programs. It can be viewed as a simple Point-to-Point or Ethernet device, which instead of receiving packets from a physical media, receives them from user space program and instead of sending packets via physical media writes them to the user space program. When a program opens /dev/net/tun, driver creates and registers corresponding net device tunX or tapX. After a program closed above devices, driver will automatically delete tunXX or tapXX device and all routes corresponding to it.

First make sure the tuntap module is included in the kernel : if you use a recent distribution, chances are that the needed modules are already build Make sure that "Kernel module loader" - module auto-loading support is enabled in your kernel. Add following line to the /etc/modules.conf: alias char-major-10-200 tun Run: depmod -a The driver will be automatically loaded when application access /dev/net/tun. Otherwise, recompile the kernel, including the configuration option CONFIG_TUN (Network device support -> Universal TUN/TAP device driver support) Make sure there is a /dev/net/tun device. (Can be created with 'mkdir /dev/net ; mknod /dev/net/tun c 10 200'). In the same way, to use masquerading, you need a kernel with the following options : CONFIG_IP_NF_CONNTRACK (Connection tracking) CONFIG_IP_NF_IPTABLES (IP tables support) CONFIG_IP_NF_NAT (Full NAT) Some of the other options in this group is probably also needed, (but the default setting should be OK).

Make sure Bochs has ne2000 support. If you have to recompile Bochs, --enable-ne2000 when running ./configure (see ) edit your .bochsrc configuration file and add something like : ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tuntap, ethdev=/dev/net/tun0, script=/path/to/tunconfig Since the tuntap interface cannot be configured until a process opens it, Bochs may run a script file for you. In this case /path/to/tunconfig should be changed to match the actual place where you'll create this script.

We'll set up a private network between the host and the guest with the following parameters: Host IP : 192.168.1.1 Guest IP : 192.168.1.2 If your parameters are different, adapt the rest of the section to suit your needs. Create the /path/to/tunconfig script : #!/bin/bash /sbin/ifconfig ${1##/*/} 192.168.1.1 The script get the interface name as the first parameter. Linux will forward incoming packets between interfaces. Make it executable :chmod 755 /path/to/tunconfig Run Bochs, install the guest OS, and set the following network parameters in the guest OS: IP: 192.168.1.2 netmask: 255.255.255.0 gateway: 192.168.1.1 nameserver: whatever is used in linux Bochs must be started by root (at least for now - the script won't have root privileges otherwise). You may also have to edit /etc/hosts.allow in the host OS and add : ALL: 192.168.1.2 Don't forget to set up the route on the guest. At this point, you should be able to ping/telnet/ftp/ssh the guest from the host and vice-versa.

We are going to set up standard masquerading configuration. Edit the /path/to/tunconfig script ans add : /sbin/iptables -D POSTROUTING -t nat -s 192.168.1.0/24 -d ! 192.168.1.0/24 -j MASQUERADE >& /dev/null /sbin/iptables -t nat -s 192.168.1.0/24 -d ! 192.168.1.0/24 -A POSTROUTING -j MASQUERADE echo 1 > /proc/sys/net/ipv4/ip_forward The configuration assumes the default policy is ACCEPT (can be examined by doing '/sbin/iptables -L') The iptables package must be installed. And voila... The host should forward the packets of the guest to the rest of your network. You could even have acces to the internet... &FIXME; add nice screenshot You may need to load other modules if you want to use other fancy protocols (ftp,etc...)

Note, if you are looking for a graphical front-end for the bochs debugger, you may want to check out BFE. This is a package written by a Bochs user which can interface with the text based Bochs debugger. No linking is necessary. It's not part of Bochs, but you may find it useful. You can now conditionally compile in a GDB like command line debugger, that allows you to set breakpoints, step through instructions, and other useful functions. If there isn't a command for something you believe is generally useful for the debugger, let me know and I'll implement it if possible. To use the debugger, you must configure Bochs with the --enable-debugger and --enable-disasm flags. For example: ./configure --enable-debugger --enable-disasm You must use flex version 2.5.4 or greater. I have heard that version 2.5.2 will not work. When you first start up Bochs, you will see the command line prompt bochs:1> From here, you may use the following commands:

c continue executing cont continue s [count] execute count instructions, default is 1 step [count] s [cpu] [count] for SMP simulation, execute count instructions on cpu, default is 1 step [cpu] [count] s all [count] for SMP simulation, execute count instructions on all cpus step all [count] Ctrl-C stop execution, and return to command line prompt Ctrl-D if at empty line on command line, exit q quit debugger and execution quit exit

NOTE: The format of 'seg', 'off', and 'addr' in these descriptions, are as follows. I don't have any way to set the current radix. hexidecimal: 0xcdef0123 decimal: 123456789 octal: 01234567 vbreak seg:off Set a virtual address instruction breakpoint vb seg:off lbreak addr Set a linear address instruction breakpoint lb addr pbreak [*] addr Set a physical address instruction breakpoint pb [*] addr (the '*' is optional for GDB compatibility) break [*] addr b [*] addr info break Display state of all current breakpoints bpe n Enable a breakpoint bpd n Disable a breakpoint delete n Delete a breakpoint del n d n

watch read addr Insert a read watch point at physical address addr watch r addr Insert a read watch point at physical address addr watch write addr Insert a write watch point at physical address addr watch w addr Insert a write watch point at physical address addr watch Display state of current memory watchpoints watch stop Stop simulation when a watchpoint is encountered (default) watch continue Do not stop simulation when a watchpoint is encountered unwatch addr Remove watchpoint to specific physical address unwatch Remove all watch points trace-mem on/off Enable/Disable memory access tracing

x /nuf addr Examine memory at linear address addr xp /nuf addr Examine memory at physical address addr n Count of how many units to display u Unit size; one of b Individual bytes h Halfwords (2 bytes) w Words (4 bytes) g Giant words (8 bytes) NOTE: these are *not* typical Intel nomenclature sizes, but they are consistent with GDB convention. f Printing format. one of x Print in hexadecimal d Print in decimal u Print in unsigned decimal o Print in octal t Print in binary n, f, and u are optional parameters. u and f default to the last values you used, or to w(words) and x(hex) if none have been supplied. n currently defaults to 1. If none of these optional parameters are used, no slash should be typed. addr is also optional. If you don't specify it, it will be the value the next address (as if you had specified n+1 in the last x command). setpmem addr datasize val Set physical memory location of size datasize to value val. crc addr1 addr2 Show CRC32 for physical memory range addr1..addr2

r|reg|regs|registers List of CPU integer registers and their contents fp|fpu List of all FPU registers and their contents mmx List of all MMX registers and their contents sse|xmm List of all SSE registers and their contents ymm List of all AVX registers and their contents sreg Show segment registers and their contents dreg Show debug registers and their contents creg Show control registers and their contents info cpu List of all CPU registers and their contents info eflags Show decoded EFLAGS register info break Information about current breakpoint status info tab Show paging address translation

set reg = expr Change a CPU register to value of expression. Currently only general purpose registers are supported, you may not change: eflags, eip, cs, ss, ds, es, fs, gs. Examples: set eax = 2+2/2 set esi = 2*eax+ebx registers List of CPU registers and their contents regs reg r

disassemble start end Disassemble instructions in given linear address range, inclusive of start, exclusive of end. Use "set $disassemble_size =" to tell debugger desired segment size. Use a value for end of less than start (or zero) if you only want the first instruction disassembled. disassemble switch-mode Switch between Intel and AT&T disassebly styles for debugger disassembler. disassemble size = n Tell debugger what segment size to use when the "disassemble" command is used. Use values of 0, 16 or 32 for n. Value of 0 means "use segment size specified by current CS segment". Default is 0. set $auto_disassemble = n Cause debugger to disassemble current instruction every time execution stops if n=1. Default is 0. Segment size of current CPU context is used for disassembly, so the "disassemble size" variable is ignored. set disassemble on The same as 'set $auto_disassemble = 1' set disassemble off The same as 'set $auto_disassemble = 0'

trace on Disassemble every executed instruction. Note that instructions which caused exceptions are not really executed, and therefore not traced. trace off Disable instruction tracing.

To use instrumentation features in bochs, you must compile in support for it. You should build a custom instrumentation library in a separate directory in the "instrument/" directory. To tell configure which instrumentation library you want to use, use the "--enable-instrumentation" option. The default library consists of a set of stubs, and the following are equivalent: ./configure [...] --enable-instrumentation ./configure [...] --enable-instrumentation="instrument/stubs" You could make a separate directory with your custom library, for example "instrument/myinstrument", copy the contents of the "instrument/stubs" directory to it, then customize it. Use: ./configure [...] --enable-instrumentation="instrument/myinstrument"

instrument [command] calls BX_INSTR_DEBUG_CMD instrumentation callback with [command]

ptime Print the current time (number of ticks since start of simulation). sb delta Insert a time break point "delta" instructions into the future ("delta" is a 64-bit integer followed by "L", for example 1000L). sba time Insert a time break point at "time" ("time" is a 64-bit integer followed by "L", for example 1000L). record filename Record console input to file filename. The file consists of zero or more lines of the form "%s %d %x", where the first word is the event type, the second is a time stamp and the third is event specific data. playback filename Playback console input from file filename. Additional input can be given directly in the console window. Events in the file will be played back at times relative to the time when the playback command was executed. print-stack [num words] Print the num words top 16-bit words on the stack. Num words defaults to 16. Only works reliably in protected mode when the base address of the stack segment is zero. modebp Toggles CPU mode switch breakpoint. ldsym [global] filename [offset] Load symbols from file filename. If the global keyword is added, then the the symbols will be visible in all contexts for which symbols have not been loaded. Offset (default is 0) is added to every symbol entry. The symbols are loaded in the current (executing) context. The symbol file consists of zero or more lines of the format "%x %s". show [string] Toggles show symbolic info (calls to begin with). show - shows current show mode show mode - show, when processor switch mode show int - show, when interrupt is happens show call - show, when call is happens show ret - show, when iret is happens show off - toggles off symbolic info show dbg-all - turn on all show flags show dbg-none - turn off all show flags

&FIXME; add links Cosimulation Instrumentation

This section covers how you can use Bochs with a remote GDB stub to debug your kernel.

The GDB stub is not active in standard Bochs binary package. So you must recompile Bochs. Download the Bochs source package, unpack it and run the configure script with the --enable-gdb-stub argument. $ ./configure --enable-gdb-stub After that, just run make and you should have a Bochs binary that contain a GDB stub in your directory.

Enable the gdbstub option in bochsrc, then just start Bochs as normal. Bochs will stop and wait for GDB to connect to the stub.

Bochs GDB stub waits for a connection on TCP port 1234. Just start GDB like this: $ gdb YOUR-KERNEL . . . (gdb) target remote localhost:1234 Remote debugging using localhost:1234 0x0000fff0 in ?? () (gdb) You are now connected to the remote GDB stub in Bochs. You are now able to set breakpoints. Use the continue (c) command to continue the simulation. Hitting ^C works. Example: Program received signal 0, Signal 0. syscall_testsuite_result (aux=0x1f11fe4) at ../rtmk/syscalls.c:33 33 { (gdb)

This section describes what is possible to do with Bochs serial port emulation. These examples use dlxlinux disk image (downloaded from http://bochs.sourceforge.net/guestos/dlxlinux3.tar.gz ) running as guest, on a debian x86 linux 2.4.19 host. For the examples to work in dlxlinux, after you login as root, you will need to kill the running gpm, as it grabs the serial port. Welcome to DLX V1.0 (C) 1995-96 Erich Boehm (C) 1995 Hannes Boehm dlx login: root Linux 1.3.89. dlx:~# ps | grep gpm 30 S0 S 0:00 /usr/bin/gpm -t bare 40 1 S 0:00 grep gpm dlx:~# kill -9 30 dlx:~#

The first example shows how to log information sent to the serial port on the guest system into a file on the host system. Update the com1: section of your configuration file: com1: enabled=1, mode=file, dev=serial.txt After you've launch dlxlinux, everything sent to the serial port will be logged to serial.txt : dlx:~# echo "logging to the serial port" > /dev/cua0 host$ cat serial.txt logging to the serial port host$

The second example shows how to connect to the guest OS, using a virtual terminal on the host OS. First, you need to find an unused virtual terminal. Typically, X uses vt7; vt8 and up are unused. On my system, I can switch from X to vt9 by pressing ctrl-alt-f9 : this virtual terminal is not used, the screen is all black. Pressing alt-f7 switches back to X. Once you found an unused vt, update the com1: section of your configuration file: com1: enabled=1, mode=term, dev=/dev/tty9 The number must be set according to the terminal you want to use (here 9). Now, launch dlxlinux. After you log in as root and kill gpm, enter the following command: dlx:~# /sbin/agetty 38400 cua0 If you switch to vt9, you can see dlx welcome banner, and the login prompt: Welcome to DLX V1.0 (C) 1995-96 Erich Boehm (C) 1995 Hannes Boehm dlx login: Note that dlxlinux is configured so you can not login as root from a serial port. If you want to login, you have to create a new user first. Also, if you plan to use this feature, the best would be to deactivate gpm in /etc/rc.d/rc.local, and add a agetty line in /etc/inittab, for example: T0:1234:respawn:/bin/agetty 38400 cua0

The third example is very similar to the second one, except that we connect to the guest OS with kermit as client, and we the connection is done through a pseudo terminal. This example uses /dev/ptyp0 and /dev/ttyp0 as pseudo terminal pair. We will tie Bochs to the controlling terminal, whereas kermit will use the slave terminal. Update the com1: section of your configuration file: com1: enabled=1, mode=term, dev=/dev/ptyp0 and lauch dlxlinux. After you log in as root, enter the command: dlx:~# /sbin/agetty 38400 cua0 Then in the host OS, launch kermit : host$ kermit -l /dev/ttyp0 C-Kermit 7.0.196, 1 Jan 2000, for Linux Copyright (C) 1985, 2000, Trustees of Columbia University in the City of New York. Type ? or HELP for help. (/tmp/) C-Kermit>connect Connecting to /dev/ttyp0, speed 0. The escape character is Ctrl-\ (ASCII 28, FS) Type the escape character followed by C to get back, or followed by ? to see other options. ---------------------------------------------------- Welcome to DLX V1.0 (C) 1995-96 Erich Boehm (C) 1995 Hannes Boehm dlx login: The same comments as for example 2 apply here.

A bootable CD-ROM has a special layout that is detected by the BIOS boot loader code, and executed if it conforms the specifications. This layout is called "El Torito Bootable CD-ROM Format Specification" and has been published by Phoenix and IBM. A copy of this spec is on Bochs tech specs page. El Torito specifies 3 ways to have a bootable CD: floppy emulation boot: A standard floppy image is burnt on the CD. In this case the BIOS has to redirect all first floppy accesses to this image and the real floppy drive becomes the second one. a "no emulation" boot: In this case the BIOS is instructed to load an arbitrary number of sectors straight into memory, and execute it. hard disk emulation: A hard disk image is burnt on the CD. The BIOS has to redirect all hard disk accesses to that image. The real hard disks are still available, with BIOS numbers 81h and up. In Bochs 2.0, hard disk emulation is not implemented in the BIOS. There are also subtilities about multiple boot-images CD-ROMs, that are not handled by Bochs. However, our BIOS may be more strict than real PC BIOSes, I don't know. But I would definitely be interested to know of any CD that can boot on real hardware, but does not in Bochs. When failing to boot from CD-ROM, the BIOS outputs the reason of the failure as an error code, in the log file, and on the screen. Here is a summary of what can happen when booting from the CD. Error code Reason 0x01 no atapi device found 0x02 no atapi cdrom found 0x03 can not read cd - BRVD 0x04 cd is not eltorito (BRVD) 0x05 cd is not eltorito (ISO TAG) 0x06 cd is not eltorito (ELTORITO TAG) 0x07 can not read cd - boot catalog 0x08 boot catalog : bad header 0x09 boot catalog : bad platform 0x0A boot catalog : bad signature 0x0B boot catalog : bootable flag not set 0x0C can not read cd - boot image 0x01 no atapi device found 0x02 no atapi cdrom found For the first two errors, an ata-*: type=cdrom is probably missing from the configuration file. This is what you get if no cdrom has been defined in Bochs conf file. 0x03 can not read cd - BRVD For this error, the cdrom support has not been compiled in Bochs, or Bochs could not open the file or device. This is what you get if Bochs is not able to read the cd. 0x04 cd is not eltorito (BRVD) 0x05 cd is not eltorito (ISO TAG) 0x06 cd is not eltorito (ELTORITO TAG) For these errors, the data has been read from the cd, but the cd does not conform to the El Torito specification. This is what you get if the cd is not bootable. 0x08 boot catalog : bad header 0x09 boot catalog : bad platform 0x0A boot catalog : bad signature 0x0B boot catalog : bootable flag not set now the cd is eltorito, but the boot catalog is corrupted, or the cd was made to boot on a ppc system. This should not happen for a x86 bootable cd. 0x07 can not read cd - boot catalog 0x0C can not read cd - boot image here, specific part of the cd could not be read. This should definitely not happen.

Since the beginning of the PC era, disks have grown in size by a factor of 10000. Due to differences between the ATA specification and BIOSes implementations, when disks reached critical sizes, it became necessary to translate the CHS geometry (cylinders, heads, sectors per track) between the BIOS (int 13h) and the ATA interface. Please refer to the ATA-FAQ and Hale Landis' document for a complete discussion of the problem. Unfortunately, there has never been any standard on the translation algorithms. Bochs implements 4 well-known algorithms, selectable in the configuration file in the "ataX-xxxx: ..., translation='algorithm'" section. Algorithm Maximum disk size Maximum logical and physical geometry (CHS) Description none 528MB (1032192 sectors) LCHS:1024/16/63 PCHS:1024/16/63 no translation is done. The CHS received at the int13h interface is sent as is to the ATA interface. large 4.2GB (8257536 sectors) LCHS:1024/128/63 PCHS:8192/16/63 a standard bitshift algorithm (named Extended-CHS) is used to translate the CHS between the int13h interface and the ATA interface. The translation is achieved by multiplying/dividing the cylinder/head count by a power of 2 (2, 4 or 8). (a factor of 16 could not be used because the head count would become 256, and MS-DOS thought this was 0) Note that the number of sectors per track is not changed, so a lower spt value will lead to a lower maximum disk size. echs synonym for large rechs 7.9GB (15482880 sectors) LCHS:1024/240/63 PCHS:15360/16/63 a revised bitshift algorithm (called Revised Extended-CHS) is used to translate the CHS between the int13h interface and the ATA interface. First the number of physical heads is forced to 15, and the number of cylinders is adjusted accordingly. Then, as in the simple extended CHS algorithm, the translation is achieved by multiplying/dividing the cylinder/head count by a power of 2 (2, 4, 8 or 16). The head count being forced to 15, it can safely be multiplied by 16 without crashing dos. Note that the number of sectors per track is not changed, so a lower spt value will lead to a lower maximum disk size. lba 8.4GB (16450560 sectors) LCHS:1024/255/63 PCHS:16320/16/63 a LBA-assisted algorithm is used to translate the CHS between the int13h interface and the ATA interface. The translation is achieved by first computing the physical size of the disk (LBA=C*H*S). Then the sectors per track is forced to 63, and the head count to 255. Then the cylinder count is computed (C=LBA/(63*255)) Note that the number of sectors per track is forced to 63 in the logical geometry, regardless of the actual geometry reported by the disk. Also note that the LBA-assisted algorithm has nothing to do with LBA access at the ATA interface. auto the best suited algorithm between none, large and lba is used Setting a specific CHS translation should be done if you use a disk dump of an actual disk, or use a real disk as a block device. You need to know which geometry was used to format the disk, and which translation was used. You must not set the translation to 'auto'. rechs translation should only be useful for Compaq users who wants to use a disk as a block device. Please report if you know any other system that use such translation. If you plan to create a new disk image (for example with bximage), format it and install an OS on it, select the "auto" translation for an automatic selection of the best algorithm based on the disk image size. Be warned that an image created with the "auto" translation might not be readable with previous versions of Bochs. Upward compatibility will be maintained. This translation applies only to int13h BIOS disk accesses. Older OSes (e.g. MS-DOS) tend to use them a lot. On modern OSes, disk accesses through BIOS int13h are limited to boot loaders. The usual rules and tricks of the installed OS still apply (ie 1024 cylinders boot limit).

Your window manager may trap the key combination you want to enter in Bochs guest OS, for example controlaltdelete. Here is a work-around: Press and hold controlalt, move your mouse cursor outside of the Bochs window. Release them, move the cursor back in the Bochs window and press delete. This should work for any key combination. If you need one key combination frequently, set it up as user key combination in your configuration file. This key combination is sent to the guest OS when you press the user button in the headerbar. Depending on the used display_library option, it may even be possible to edit the shortcut before sending it.

Since Bochs 1.4 it is possible to use VESA graphics. There are some limitations in the current implementation, but in general it should work ok (we have run several test programs, the XFree86 VESA display driver, etc.) In order to use VESA VBE, you need to enable it in your bochsrc by setting the vga option to vbe. Finally, you need to use the LGPL'd VGABIOS as vgaromimage option for applications to correctly detect VESA support. The VGABIOS is already included in the Bochs release, so no separate download is necessary. To take advantage of the VBE, you must tell Bochs to use the LGPL'd VGA BIOS version 0.4c or higher. A current version of the VGA BIOS will work. Current limitations: 4bpp modes support is incomplete (8, 15, 16, 24 and 32bpp should work) banked mode is very slow (if you can, just use Linear Frame Buffering instead!) only 320x200, 640x400, 640x480, 800x600, 1024x768 are currently supported Interesting Facts: You need a display driver capable of using the VESA BIOS for this to work (a recent XFree86 will do, Windows 9x/NT/2K/XP probably will not work 'out of the box'. Currently the VBE2 extension should be supported ok

This was contributed by Martin Bochnig in February 2004. Instructions for Win95/98: ========================== I can only confirm that SciTech finally made a VBE driver for Windows. It works out of the box, at least with win95 as guest OS, provided you use Bochs 2.1 with the LGPL vgabios. Here is how I did it : - install win95 with the vga driver. - download sdd 7 beta from - download pmhelp.vxd from - copy pmhelp.vxd to the win95 system directory - install sdd7 800x600 and 1024x768 in 16 and 24 bpp modes here. I did not try 32bpp. This was contributed by Stanislav Shwartsman in September 2004. Instructions for Win2000/XP: ============================ Bochs VBE Display Drivers for Windows NT/2000

Since Bochs 2.2 it is possible to use Cirrus SVGA graphics. The Cirrus device supports both ISA and PCI depending on the bochsrc settings. If PCI is disabled or the Cirrus card is not assigned to a PCI slot, it appears as a CL-GD5430 ISA with 2MB VRAM. If you assign the Cirrus card to a PCI slot, it appears as a CL-GD5446 PCI with 4MB VRAM. In order to use Cirrus SVGA, you need to compile Bochs using the --enable-clgd54xx option and enable it in your bochsrc by setting the vga option to cirrus. Finally, you need to use the Cirrus version of the LGPL'd VGABIOS as vgaromimage option for applications to correctly detect Cirrus support. # Enable CL-GD5446 PCI vga: extension=cirrus vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest-cirrus i440fxsupport: enabled=1, slot1=cirrus The VGABIOS is already included in the Bochs release, so no separate download is necessary.

Bochs can handle independent disk image format for each disk present on the ata interfaces. The disk image type is selected in the configuration file by the "mode" option of the ataX-xxx directives. Example: ata0-master: type=disk, mode=flat, path=10M.sample, cylinders=306, heads=4, spt=17 If unspecified, the default "mode" is flat. Name Description Features flat one file, flat layout accessible with mtools or winimage-like tools concat multiple files, concatenated mappable to contained partitions external accessed through an external C++ class developer specific, needs a C++ class at compile time dll accessed through a DLL developer specific, windows only sparse up to 10 layers stackable files commitable, rollbackable, growing vmware3 vmware3 disk support vmware version 3 compatibility vmware4 vmware4 disk support vmware version 4 compatibility undoable flat file with a commitable redolog commitable, rollbackable growing one growing file growing volatile flat file with a volatile redolog always rollbacked vvfat local directory appears as VFAT disk (with volatile redolog) optional commit or rollback

In flat mode, all sectors of the harddisk are stored in one flat file, in lba order.

Flat disk images can be created with the bximage utility (see for more information).

The "path" option of the ataX-xxx directive in the configuration file must point to the flat image file.

Flat images content can be accessed from the host by the following tools : mtools (see ) mount with a loopback (see ) Winimage / DiskExplorer (see ) Bochs Tools (see )

Flat mode is Bochs default harddisk layout. This is also the layout of disk images provided on Bochs websites.

On some host OSes, Bochs flat disk images are limited to 2GiB.

In concat mode, all sectors of the harddisk are stored in several flat files, in lba order.

Disk images for the usage in 'concat' mode can be created with the bximage utility (see for more information).

The "path" option of the ataX-xxx directive in the configuration file must point to the first file (e.g. win95-1). The lower layer files names are found by adding 1 to the last character (e.g. win95-2, win95-3, etc.).

If every single file contains a complete partition, they can be accessed with same tools as the 'flat' mode images.

If the partition sizes and file sizes are set up correctly, this allows you to store each partition in a separate file, which is very convenient if you want to operate on a single partition (e.g. mount with loopback, create file system, fsck, etc.).

On some host OSes, there is a limit of 2GiB per file.

This mode is only useful for developers and needs an additional C++ class compiled in, or an additional DLL linked to Bochs.

Sparse disk support has been added by JustinSB. Sparse disk features are: Large hard drive can be created, and only used space will be stored in the file. In practice, on Unix, this is not a large gain as it is done anyway. Multiple sparse drive images can be mounted on top of each other. Writes go to the top image. This allows several similar configurations to share a master "base" file, and also allows file system rollback or no-write options. Up to 10 disk images can be layered on top of each other.

Sparse disk images must be created with the bximage utility (see for more information). Be sure to enter "sparse" when selecting the image type.

The "path" option of the ataX-xxx directive in the configuration file must point to the top layered file. The lower layer files names are found by substracting 1 from the last character (must be a digit)

No external tool support Sparse disk images yet.

Create a sparse disk image using bximage. Set size to eg 10GB. Only allocated space will be stored, so your drive image should be only about as large as the files stored on it.

Create a sparse disk image called "c.img.0". Point .bochsrc at "c.img.0". In bochs, install your favorite OS. Switch off bochs. Create a sparse disk image (of the same size) and name it "c.img.1". Point .bochsrc at "c.img.1" "c.img.0" is visible, but all writes go to "c.img.1". After using bochs, you can simply delete "c.img.1" to undo changes and go back to a clean OS install.

Create a sparse disk image called "c.img.0". Point .bochsrc at "c.img.0". In bochs, install your favorite OS. Switch off bochs. Create a sparse disk image (of the same size) and name it "c.img.1". Point .bochsrc at "c.img.1" "c.img.0" is visible, but all writes go to "c.img.1". After using bochs, if you want to keep the changes, use the (currently non-existent) merge utility to make a single unified drive image. Alternatively simply create a new partition on top called "c.img.2".

Create a sparse disk image called "base.img". Point .bochsrc at "base.img". In bochs, install your favorite OS. Switch off bochs. Create a sparse disk image (of the same size) and name it "www.img.1". Make "wwww.img.0" a symlink to "base.img". Point .bochsrc at "www.img.1". Using bochs, install a webserver. Create a symlink to "base.img" called "db.img.0". Create a sparse disk image (of the same size) and name it "db.img.1". Point .bochsrc at "db.img.1". Using bochs, install a database server. Now both a database server and webserver can be run in separate virtual machines, but they share the common OS image, saving drive space.

There is a need for supporting utilities (yet unwritten) : to merge two sparse disk images into a single image to defragment a sparse disk image and remove unused space

Sharvil Nanavati has added vmware3/4 disk image support into Bochs for Net Integration Technologies, Inc. You should be able to use disk images created by vmware version 3 and 4.

Create such disk image with vmware version 3 or 4.

The "path" option of the ataX-xxx directive in the configuration file must point to the vmware3/4 disk image.

&FIXME; give a look at vmware3/4 tools : disk image creation, etc.

If you want to use an existing vmware3/4 disk image.

Only vmware versions 3 and 4 disk image files are supported.

Undoable disks are commitable/rollbackable disk images. An undoable disk is based on a read-only flat image (see ), associated with a growing redolog, that contains all changes (writes) made to the flat image content. This redolog is dynamically created at runtime, if it does not previously exists. All writes go to the redolog, reads are done from the redolog if previously written, or from the flat file otherwise. If unspecified with the "journal" option of the ataX-xxx directive, the redolog file name is created by adding a ".redolog" suffix to the flat image name. File size of the redolog can grow up to the total disk size plus a small overhead due to internal data management (about 3% for a 32MiB disk, less than 0.5% for a 2GiB disk). After a run, the redolog will still be present, so the changes are still visible the next time you run Bochs with this disk image. After a run, the redolog can be committed (merged) to the flat image with the bxcommit utility. After a run, the redolog can be rollbacked (discarded) by simply deleting the redolog file. In this mode, the flat file is always open in read-only mode, so it can safely be stored on a read-only medium (for example on a cdrom).

The flat disk images must be created with the bximage utility (see for more information). The growing redolog is created automatically if needed.

The "path" option of the ataX-xxx directive in the configuration file must be the flat image name. The redolog name can be set with the "journal" option of the same directive. If not set, the redolog name is created by adding the ".redolog" suffix to the flat image name.

See for tools to access the flat disk image content. The up-to-date content can only be seen after you commit the redolog to the flat file with the bxcommit utility.

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Growing disk images start as a small files, and grow whenever new data is written to them. Once a sector is written in the growing file, subsequent writes to the same sector will happen in place. File size of Growing disk images can go up to the total disk size plus a small overhead due to internal data management. (about 3% for a 32MiB disk, less than 0.5% for a 2GiB disk).

Growing disk images must be created with the bximage utility (see for more information). Be sure to enter "growing" when selecting the image type.

The "path" option of the ataX-xxx directive in the configuration file must be the growing image name.

No external tool support Growing disk images yet.

Growing disk images can be used whenever you want to maximize disk space. However, please note that Bochs will not check if enough disk space is available before writing new data. If no disk space is available, a panic will occur.

&FIXME; to be completed

Volatile disks are always-rollbacked disk images. An volatile disk is based on a read-only flat image (see ), associated with a growing temporary redolog, that contains all changes (writes) made to the flat image content. All data written to the disk image are lost at the end of the Bochs session. The redolog is dynamically created at runtime, when Bochs starts, and is deleted when Bochs closes (win32) or just after it has been created (Unix). All writes go to the redolog, reads are done from the redolog if previously written, or from the flat file otherwise. If unspecified with the "journal" option of the ataX-xxx directive, the redolog file name is created by adding a ".redolog" suffix to the flat image name. File size of the redolog can grow up to the total disk size plus a small overhead due to internal data management (about 3% for a 32MiB disk, less than 0.5% for a 2GiB disk). After a run, the redolog is not any more present, so the changes are discarded. In this mode, the flat file is always open in read-only mode, so it can safely be stored on a read-only medium (for example on a cdrom).

The flat disk images must be created with the bximage utility (see for more information). The growing redolog is created automatically.

The "path" option of the ataX-xxx directive in the configuration file must be the flat image name. The redolog name can be set with the "journal" option of the same directive. If not set, the redolog name is created by adding the ".redolog" suffix to the flat image name. A random suffix is also appended to the redolog name.

See for tools to access the flat disk image content.

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The "vvfat" disk image mode is mostly a port of Qemu's "virtual VFAT" block driver (written by Johannes E. Schindelin). It supports the read-only part of this implementation plus some additions. The structures of the virtual disk are created from the contents of the specified local directory when Bochs is starting. All writes to this virtual disk go to a volatile redolog and when closing Bochs, the user can decide whether or not to commit the changes. If "No" is seclected, all changes will be lost when Bochs quits and the files of the local directory are not modified. Otherwise the changes of files and directories are committed. WARNING: Don't use important data without backup in the "vvfat" directory when using this "optional commit" feature. In addition to Qemu's "vvfat" implementation the Bochs one supports configurable disk geometry, FAT32 and reading MBR and/or boot sector from file. When using the autodetection feature, the CHS values 1024/16/63 (Qemu defaults) are used. To use an MBR image file from a real disk it must be named vvfat_mbr.bin and placed in the specified directory. Bochs uses the geometry and file system type from this file and doesn't show it on the virtual disk. The same applies to a boot sector image file, but it must be named vvfat_boot.bin. Using both image file is also possible if they match (grabbed from the same disk). FAT32 is enabled for disk with minimum 2 GB size, or if MBR / boot sector image enable this filesystem. When using "vvfat" for a floppy, FAT12 is used (1.44M media only). In all other cases FAT16 is used. Long filename support is always present. Special FAT file attributes are stored in a special file named vvfat_attr.cfg. When using the "optional commit" feature, modified attributes are saved to this file. The "optional commit" also supports setting the file modification date and time.

Not necessary. The directory must exist before running Bochs.

The "path" option of the ataX-xxx directive in the configuration file must point to an existing local directory. The redolog name can be set with the "journal" option of the same directive. If not set, the redolog name is created by adding the filename "vvfat.dir.redolog" to the path. A random suffix is also appended to the redolog name.

You can use your favourite file manager to copy file to the directory you'd like to use. The directory should not be modified while Bochs is running.

Accessing files of the host hard drive is only possible with vvfat.

There is no runtime write support present yet. All changes are written to the volatile redolog and they can only be committed on Bochs exit. When using the MBR from image file only the first partition is used and it must be of type FAT16 or FAT32. FAT12 can be used for the floppy only. An extended partition or other file system types are not supported.

Bximage is an easy to use console based tool for creating disk images, particularly for use with Bochs. It is completely interactive if no command line arguments are used. It can be switched to a non-interactive mode if all required parameters are given in the command line. When you run bximage without one of the following options, it will appear in interactive mode and ask for all required parameters to create an image. -fd Create a floppy image. -hd Create a hard disk image. -mode=... Image mode (for hard disks only - see the bochsrc sample for supported options). -size=... Image size in megabytes (e.g. 1.44 for floppy image, 10 for hard disk image). -q Quiet mode (don't prompt for user input). Without this option bximage uses the command line parameters as defaults for the interactive mode. If this option is given and one of the required parameters is missing, bximage will fall back to interactive mode. --help Print a summary of the command line options for bximage and exit. The filename parameter specifies the name of the image to be created. For an example of the usage, refer to .

This tool can commit redologs into flat images. For now, only "undoable" redologs to flat image commits are supported. Sparse disk image commits may be added in the future. This tool is completely interactive, and does not need any command line parameter. Bxcommit asks for the flat image name, the redolog name, and whether to remove to redolog file after it commits it. Session example : $ ./bxcommit ======================================================================== bxcommit Undoable Disk Image Commit Tool for Bochs ======================================================================== What is the flat image name? [c.img] myfile.img What is the redolog name? [myfile.img.redolog] toapply.redolog Shall I remove the redolog afterwards? [yes]

In the past several tweaks were necessary to install a guest OS inside of Bochs. Nowadays it's almost the same as installing it on a real machine. There are only a few Bochs specific issues you should know about. Note that we cannot give you a full installation guide if you don't know how to install an OS in the real world. The following remarks apply to all guest OS installations. Some specific issues are reported in the next sections. First of all you need the installation media or image (floppy/CD/DVD). For platforms that don't support raw device access it might be necessary to create an image from the media. You must read the message regarding software licenses in before you install or use a commercial guest operating system in Bochs. Then you need to create a hard drive image with bximage. For the required size see the documentation of the OS you'd like to install. See how to create the image. Finally you have to create configuration for your guest OS. You can edit the sample configuration distributed with Bochs or use the configuration interface to adjust the settings. Check the documentation of your guest OS for the required memory size, cpu speed and supported hardware. Now you should be able to run Bochs and start the installation process. Depending on the host cpu speed and the size of the guest OS it can take a few minutes or even some hours. What disk images are available. What works Known problems

Contributed by Alexander Schuch.

Knoppix is a live CD (700M) or live DVD (3.2G) based on Debian GNU/Linux, with lots of ready-to-run programs (web browser, office suite, a few games, and more), using KDE as desktop environment. It can be booted directly from CD, without any installation needed. You can download it from knoppix.org.

As Knoppix runs completely from CD/DVD, you don't need to setup a hard disk. You just need to set up the location of the downloaded ISO image in your bochsrc, and make Bochs boot from it. Because Knoppix contains a graphical user interface, and has no other storage space but the emulated RAM, it needs at least 128MB of it, see megs option. Furthermore, you need to enable VBE support in Bochs (see ).

There is nothing more to do! Just start Bochs and wait for Knoppix to load... You are logged in as normal user, if you want to become super user, just su. There is no password needed (empty password).

Contributed by Alexander Schuch. This section describes how to install FreeBSD 5.2.1 (miniinst) inside of Bochs, using an ISO image.

As 5.2.1-RELEASE-i386-miniinst.iso (240M) is no longer available from the FreeBSD FTP server, you might want to ask a (file) search engine of your choice for a download location. Once you downloaded the file, you should check its integrity using the provided MD5 checksum from the FreeBSD 5.2.1 release announcement.

Create a new hard disk image using bximage (see ) with a size of at least 350M, as the standard installation uses 280M on its own. Next, you need to setup your bochsrc so that Bochs knows about your (still empty) hard disk, as well as about your ISO image. Make Bochs boot from CD-ROM and start the emulation.

This is just a very short step-by-step installation guide for FreeBSD in Bochs. It doesn't explain what you do nor why you do it, it just tells you how to do it. For in-deepth information refer to the FreeBSD handbook: Installing FreeBSD. FreeBSD boots up and shows a nice (text-mode) boot option screen. Just press return there, that is, use the default option. After loading the kernel and needed device drivers, select 'Standard' in the installation menu. A fdisk like partition program is loaded next, where you just press A to use the entire disk, followed by Q to finish the selection. The next dialog asks for the boot manager you want to use. Select 'Standard' and continue. In the Disklabel Editor, you have to setup the layout of your partition. If your (virtual) hard disk is large enough, you can press A for auto-layout. However, you need to make sure that the /usr partition is at least 250M large, or you will end up with a 'disk full' error message during installation. If this is not the case, select one partition after another and press D to delete it again. After you deleted all partitions, create two new ones. The first one will be a swap partition; press C, enter '32M' as size and select 'Swap' from the dialog. Press C again, and accept the remaining capacity for your filesystem partition. Choose 'FS' as partition type and enter '/' (slash) as mount point. Your partition layout is complete now; press Q to leave the editor. This 'all-in-one' partition layout is not recommended for a FreeBSD installation on a real box; use 'auto-layout' or something comparable to that there. You now can choose what set of programs/files (distribution) you want to install. Take 'User' (option 8), and select 'No' when asked to install the ports collection. You are back in the distribution selection, where you select the first item, called 'Exit'. Choose to install from 'CD/DVD' and answer the 'Are you sure?' dialog with 'yes'. Now, while FreeBSD installs, it is a very good time to take a look at the FreeBSD documentation, especially the FreeBSD handbook and the FreeBSD FAQ.

All files are installed on your (virtual) hard disk now, and FreeBSD is ready for getting set up. As this is a very basic FreeBSD installation, you just answer 'no' to nearly all questions, but the one about your mouse: Answer 'yes' for PS/2 mouse, and choose 'Exit' at mouse configuration. The miniinst FreeBSD ISO image contains nearly no binary packages, so don't browse the package collection. Then, when asked to create a new user account, answer 'yes' and create a new user called 'bochs' (or whatever you like). You might want to use /bin/csh or /bin/tcsh as shell rather than /bin/sh. Next, you are asked for the super user (root) password. The installation is finished now, there is no need to visit the general configuration menu again - answer 'no' to that question. FreeBSD will then reboot. Shutdown Bochs, as soon as the (virtual) computer boots.

Open your bochsrc and change the boot sequence, so that Bochs will boot from hard disk, rather than from CD-ROM from now on. Start Bochs again and watch the FreeBSD boot process. Your keyboard might use the wrong keymap, so login (into FreeBSD) as super user and use /stand/sysinstall to start the FreeBSD configuration program. Choose 'keymap' and select the keymap you want to use. You have successfully installed FreeBSD now. You might want to shutdown FreeBSD using shutdown -h now, quit Bochs, and create a backup of your hard disk image, before you start playing around.

You must read the message regarding software licenses in before you install or use MS-DOS, OS/2, DR-DOS, or any other DOS as a guest operating system in Bochs.

To access your CDROM in DOS, you must download an IDE CDROM driver. Bochs emulates a very generic CDROM drive, and several drivers are known to work. Others don't. This section describes how to set up your config.sys and autoexec.bat to enable the CDROM. The drivers that have been reported to work are OAKCDROM.SYS that comes with several versions of Windows and SBIDE.SYS version 1.21 from Creative Labs To get it, go to Creative Labs web site, click on Support, then click Download Files. You get to a screen where you must select the operating system and the product for which you want the driver. Choose DOS as the operating system, and "CD-ROM: 4x and above" as the product. There are several choices, but you want sbide121.exe from April 15, 1997. Version 2.0 does not work. The download file is a self-extracting ZIP file, so on DOS or Windows you just run it; on other platforms you can try using the unzip command. The driver is called SBIDE.SYS. and OAKCDROM.SYS that comes with several versions of Windows. Copy the driver to your boot disk, and then set up the startup files as follows. config.sys: device=himem.sys device=oakcdrom.sys /D:CD001 -or- device=sbide.sys /D:CD001 /P:1f0,14,3f6 autoexec.bat: mscdex.exe /M:10 /D:CD001 If the files mentioned in config.sys and autoexec.bat are not in the root directory, give the full pathname, like c:\windows\himem.sys.

To use the SB16 device in DOS you need to load a driver for it. The file SBBASIC.EXE contains a self-extracting archive with all required file. After unpacking it to C:\SB16 you can execute INSTALL.EXE to install the driver. The file DISK.ID should contain the version string SDR-31STD-1-US (Revision 1).

On the Web there are bootdisks available for most of the DOS versions ever released, but some of them have been reported to fail in Bochs. The bootdisk for MS-DOS 1.25 contains a boot sector of a newer DOS version, so it would fail on real hardware, too. The floppy image for MS-DOS 2.11 has a boot sector that tries to boot from hard disk instead of the floppy.

You must read the message regarding software licenses in before you install Windows NT 4.0 as a guest operating system in Bochs. Here are the known issues about installing and running Windows NT4.0 : If you want to use the LGPL'd VGABIOS to install Windows NT 4.0 you'll need version 0.4c or higher. With older versions you'll get a black screen after first reboot. to log in you must press ctrl-alt-del, and it is likely that the window manager will trap this key combination. You can either use the trick described in or define a user short-cut (callable through the user short-cut gui button) in you configuration file, for example: user_shortcut: keys=ctrl-alt-del For installing and using Windows NT it is necessary to limit the maximum CPUID to 3. In the configuration file you need to add a line like this: cpuid: cpuid_limit_winnt=1

You must read the message regarding software licenses in before you install Windows 2000 as a guest operating system in Bochs.

You must read the message regarding software licenses in before you install Windows 2000 Server as a guest operating system in Bochs.

You must read the message regarding software licenses in before you install Windows XP as a guest operating system in Bochs. Windows XP has been reported to install from the CDROM, and run inside Bochs. The only known issue is to set the IPS to, at least, a value of 10000000.

Contributed by Carl Sopchak You must read the message regarding software licenses in before you install SCO OpenServer 5.0.5 as a guest operating system in Bochs. Back in April and May of 2002, I did some work on Bochs in order to get it to install and boot SCO's OpenServer 5.0.5 (OSR5). Since that time, I have had several e-mails asking about this error message or that. The newsgroup posts done at the time had all of the information that I knew, so I pointed people there. (I had not used Bochs since...) In February of 2003, I got another such e-mail. Since the sender indicated they were willing to pay me to get this going for them, I agreed to spend a few hours on it (for free, which is not common :-}). Subsequently, I decided to document this once and for all. (I did not charge anyone anything, this time...) Note: These steps were originally used with Bochs 1.4.1 (or thereabouts, since I was using CVS heavily at the time). It is possible (likely) that later versions of Bochs are more tolerant/bug free, and this install may be abbreviated. However, I have not tried to streamline it at all. These steps were performed and confirmed using Bochs version 2.0.2, and SCO OpenServer version 5.0.5. The host OS was Red Hat Linux 8.0. First, I downloaded the tarball, and extracted the source tree. I decided to use the tarball instead of the RPM so that I knew what options were compiled in, etc. linux-$ tar -xzvf bochs-2.0.2.tar.gz Next, I configured and compiled Bochs... linux-$ cd bochs-2.0.2 linux-$ ./configure --enable-cdrom --enable-ne2000 --enable-host-specific-asms linux-$ make The --enable-host-specific-asms should only be used if the host OS is an Intel x86 based OS. I then created my disk image: linux-$ ./bximage ======================================================================== bximage Disk Image Creation Tool for Bochs ======================================================================== Do you want to create a floppy disk image or a hard disk image? Please type hd or fd. [hd] hd What kind of image should I create? Please type flat, sparse or growing. [flat] Enter the hard disk size in megabytes, between 1 and 32255 [10] 2048 I will create a hard disk image with cyl=4161 heads=16 sectors per track=63 total sectors=4194288 total size=2047.99 megabytes What should I name the image? [c.img] hd0.img Writing: [] Done. I wrote 2147475456 bytes to hd0.img. The following line should appear in your .bochsrc: ata0-master: type=disk, path="hd0.img", cylinders=4161, heads=16, spt=63 I then created my .bochsrc file. I did this via the interactive portion of Bochs, with the end result as follows: floppya: 1_44="/dev/fd0", status=inserted floppyb: 1_44="b.img", status=inserted ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14 ata0-master: type=disk, path="hd0.img", cylinders=4161, heads=16, spt=63, translation=auto, biosdetect=auto, model="Generic 1234" ata0-slave: type=cdrom, path="/dev/cdrom", status=inserted, biosdetect=auto, model="Generic 1234" ata1: enabled=0 ata2: enabled=0 ata3: enabled=0 romimage: file=bios/BIOS-bochs-latest vgaromimage: file=bios/VGABIOS-lgpl-latest megs: 64 parport1: enabled=1, file="lp.pipe" com1: enabled=0 # no sb16 boot: cdrom floppy_bootsig_check: disabled=0 vga_update_interval: 300000 keyboard_serial_delay: 250 keyboard_paste_delay: 100000 cpu: ips=3000000 clock: sync=realtime, time0=0 text_snapshot_check: 0 mouse: enabled=0 private_colormap: enabled=0 i440fxsupport: enabled=0 # no ne2k # no loader log: osr5.log logprefix: %t-%e-%i%d debugger_log: - panic: action=ask error: action=report info: action=report debug: action=ignore pass: action=fatal keyboard_mapping: enabled=0, map= keyboard_type: mf user_shortcut: keys=none config_interface: textconfig display_library: x Some important things to note are that you want to boot from the cdrom, and you do NOT want the ne2000 card configured initially. (We'll add that later...) At this point, Bochs is ready to roll! Insert the OSR5 install CD into the drive, and start Bochs. You should soon see the SCO "boot:" prompt: SCO OpenServer(TM) Release 5 boot : defbootstr disable=fdi,dptr Note the disable= parameter that you need. These two SCO drivers cause the install to fail, so they need to be disabled for the install boot. You will not need this once OSR5 is installed. During the install of OSR5, there are two default configuration answers that need to be changed. For the hard disk setup, you should turn bad tracking off, since it's unnecessary on an emulated disk. (It won't hurt to do it, it will just take a VERY long time!) For the network setup, change the network card to Deferred. You can change other settings, if you so desire. However, I would do the initial install with as little configured as you can get away with, then add whatever else is needed (one step at a time) after the initial install completes. Let the install copy the files. Go get lunch. Take a nap. Go have dinner... This can take a LONG time. On my Pentium 4 1.7GHz system, this step took just over eight hours! (BTW, it was MUCH longer in version 1.4.1. Great job, guys!) After the install finishes, you will need to change the following lines in .bochsrc file: ne2k: ioaddr=0x300, irq=10, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0 boot: disk Obviously, if you're not using Linux, the ethmode and ethdev values on the ne2k line will be different. Also, since Bochs uses "raw" network card access, you'll have to "setuid root" on the Bochs executable: linux-$ chown root bochs linux-$ chmod u+s bochs (If there is a way to give a "normal user" CAP_NET_RAW capability, that would be an alternative. I don't know how to do that...) Restart Bochs. Now, you can just press Enter at the OSR5 boot: prompt, because the offending drivers have been linked out of the kernel. Before you configure the network card, I'd strongly suggest getting the latest "nat" driver from SCO. Version 5.0.5b of this driver, according to the SCO web site, "correct[s] possible system lockup under high load due to internal buffer overflow." The driver can be found here. To get the Disk Image file into SCO, I downloaded the VOL.000.000 file to my linux box, and used tar to get it on to a floppy: linux-$ tar -cvf /dev/fd0 VOL.000.000 I then used tar within OSR5 to move it from the floppy to the /tmp directory: osr5-# cd /tmp osr5-# tar -xvf /dev/fd0135ds18 You can then use 'custom' to install the driver from the image file. You will then want to use 'scoadmin network' to configure the network card. Choose the Novell NE2000 card, and set the parameters to match the ne2k: line in the .bochsrc file. DO NOT have OSR5 look for the card, as Bochs may likely crash. (It did in version 1.4.1.) You can also configure a printer, if you want. Using the spoolpipe utility that I wrote (which can be found in Bochs' misc directory), you can print from OSR5 through the parallel port, and you'll hardly notice that the printing is going through an extra layer of operating system! (You could also set up a printer using network printing, if the printer is not on the host machine...) Obviously, dont forget to apply the release supplements and other patches that are considered "must haves" for OSR5: rs505a, oss600a, oss497b (others?). That's about as far as I have got. I played around with OSR5 within Bochs a bit, but I can by no means say that I did any kind of real testing, let alone exhaustive testing. And of course, YMMV! :-)