%bochsdefs; ]> KevinLawton BryceDenney MichaelCalabrese Vasudeva

Bochs is a program that simulates a complete Intel x86 computer. It can be configured to act like a 286, 386, 486, Pentium, or Pentium Pro. 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 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, 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 software. 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's 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. Plex86, Kevin Lawton's current project, is working toward an open-source x86 simulator with virtualization. To do anything interesting in the simulated machine, Bochs needs to communicate 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 95, for example. For this reason, certain features are supported on some host platforms and not others. On 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 $25... &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 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 Source Forge.

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 300 subscribers. The latest version has been downloaded over 40,000 times from SourceForge, not counting mirrors 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 often 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. Also, it has been used as a reference model to test 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 to program under 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, "Will Bochs work for me?" &FIXME; You can also find more detailed testing information on the testing status page on the &bochswebsite;. The testing status page tells which combinations of host platform and guest platform have been tried by other Bochs users.

Bochs is copyrighted by MandrakeSoft S.A. MandrakeSoft has web sites at http://mandrakesoft.com and http://www.linux-mandrake.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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

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 on of several families of Intel hardware. Some Pentium features are supported, such as the Time Stamp Counter. Pentium Pro Emulation Incomplete A few Pentium Pro features are supported, such as an on-chip APIC for SMP simulation. Cmd Line Debugger Yes Powerful command line debugger (optional) that lets you stop execution and examine registers and memory, set breakpoints, etc. Floating Point Yes Uses software floating point routines written by Bill Metzenthen VGA Yes VGA color graphics emulation in a window Floppy disk Yes Supports floppy disk images on all platforms: 1.44M 3.5", 1.2M 5.25", and 720K 3.5". On Unix and Windows NT/2000, Bochs can access the physical floppy drive. Hard disk Yes Emulates one or two AT/IDE hard drives via image files. No physical hard disk access is supported, primarily for safety reasons. Only two IDE devices, total, are supported. So you can have two hard disks, or one hard disk and one CDROM. Keyboard Yes Emulates a PS/2 keyboard with North American key mappings. Keyboards with other key mappings are reported to have problems with special keys and punctuation. Mouse Yes Emulates a PS/2 mouse with 3 buttons. 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. Unfortuately, with the current implementation, the guest OS can talk to any machine on the network BUT NOT the host machine. CDROM Yes Emulates an IDE CDROM. The CDROM can read from an ISO disk image on any platform. On Windows (95/98/NT/2000), Linux, SunOS, FreeBSD, NetBSD, Amiga/MorphOS, and BeOSComing soon, hopefully in v1.3, Bochs can read from the physical cdrom. When the CDROM is enabled, only one hard disk can be used. 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 Not quite The serial port (single 8259 UART emulation) is not really usable yet. The interface to the emulated CPU is mostly working, but it needs some work before it can talk to a raw serial port or to a pseudo terminal. 16/32 bit addressing Yes 16 or 32 bit operand sizes, stack size, and addressing v8086/paging Yes Virtual-8086 mode and paging PIC Yes Master and slave programmable interrupt controller. CMOS functions Yes CMOS functions Dynamic Translation No Because Bochs is designed to be portable, it does not attempt to do any dynamic code translation or virtualization. See What is Bochs? for details. Simulate a Multiprocessor Yes Bochs can be configured to simulate up to 15 processors. This feature is still experimental, but it can boot Linux 2.2 kernels 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.

Unix/X11 X windows has always been well supported because it was Kevin's 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. Win32 This port was done by David Ross and is now maintained by Don Becker. You can compile with MS Visual C++ 5.0 or 6.0, or cygwin Cygwin is a free Unix-like environment for Windows written by Steve Chamberlain and now maintained by RedHat. Download it from--you guessed it--www.cygwin.com . See for compile instructions. BeOS Kevin Lawton did 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 Inside Beos magazine (www.insidebeos.com), took over the BeOS port. Uses the same compile and install process as Unix. MacOS X Emmanuel Mailliard ported the Macintosh code to MacOS X with Carbon API. He has been too busy to maintain it, so if you are interested in working on it, contact the &devlist;. Macintosh David Batterham drbatter@socs.uts.edu.au or drbatter@yahoo.com ported bochs to the Mac. He compiled with CodeWarrior Pro R1 (CW12). To compile, you have to build headers and Makefiles on a Unix machine using "configure --with-macos". Check out David's MacBochs website. David has not had time to maintain the page or the Mac port since early 2000. If you have Mac development tools and want to contribute, contact the &devlist;. Amiga MorphOS This port is written and maintained by Nicholai Benalal. OS/2 Nick Behnken used PE2LX to translate David Ross's Win32 port to an OS/2 program. This hasn't been updated in more than a year, 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. His latest sources are at http://www.os2world.com/emulator/computer.html. 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, makers of the Linux-Mandrake distribution. 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. Kevin is presently working on a PC virtualization project called plex86 and no longer maintain bochs. 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 current admins on this project are Bryce Denney, Greg Alexander, and Don Becker. Tell me about peformance when running bochs? Because Bochs emulates every x86 instruction and all the devices in a PC system, it does not reach high emulation speeds. Kevin reported approximately 1.5MIPS using bochs on a 400Mhz PII Linux machine. Users who have an x86 processor and want the highest emulation speeds may want to consider PC virtualization sotware uch as plex86 (free) or vmware (commercial). Does bochs use a disk partition to install the OS? No. You use 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 Win95 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 Win95 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? Not that I am aware of. Do you know of any snapshots of Bochs running Win95? Yes! Look for "screen shots" on the Bochs home page or on other Bochs sites. Does bochs support a CDROM? Yes, a CDROM is supported in Linux, Windows, and OpenBSD. The CDROM drivers for bochs allow the guest operating system to access the host operating system's CDROM data directly. Does bochs support a sound device? Yes, there is Sound Blaster emulation support for Windows and Linux. Does bochs support a network card? Supposedly yes. There is emulation for an NE2000 NIC in the current releases, though I have not heard whether it works or not. If you try it, please fill out a testing form or bug report. 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 your 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.

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@cvs.bochs.sourceforge.net:/cvsroot/bochs login (Logging in to anonymous@cvs.bochs.sourceforge.net) CVS password: (there is no password, just press Enter) user$ cvs -z3 -d:pserver:anonymous@cvs.bochs.sourceforge.net:/cvsroot/bochs checkout bochs cvs server: Updating bochs U bochs/.bochsrc U bochs/.conf.AIX.4.3.1 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 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$ _

If you have write access to the Bochs CVS tree, the checkout command is different for you. See the Developers Guide &FIXME; not written yet. For now, look at http://sourceforge.net/cvs/?group_id=12580 for instructions. See "Developer CVS access using SSH." 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 - P is the same as U, as far as I can tell 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 1.2.1 (bugfix1) REL_1_2_1_FINAL 1.2 REL_1_2_FINAL 1.1 (bugfix1) REL_1_1_BASE 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 March 25, 2000 REL-bochs-2000-03-25 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 accidently 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.

unzip into some directory. Look for DOC-win32.html for more instructions. Quick start: find dlxlinux/start.bat and double click &FIXME; Someone needs to write this.

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. Debian packages are available for Bochs as well, but this section talks deals with RPMs. 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." Once you have the package on your local disk, you should be able to install it as follows Many distributions have their own RPM installer program, often graphical, and they should work as well. 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. If RPM installation fails, try running rpm -e bochs first to erase any old bochs RPMs. VGA Font failure? For now, look at old bochs docs for now for instructions on installing the VGA font by hand. &FIXME; Missing RPM dependencies? Try --nodeps option. The Bochs RPM installs three new commands and associated manual pages: bochs, bochs-dlx, and bximage. First, let's try out the DLX Linux demo by typing bochs-dlx. This command is installed into /usr/local/bin, so you might need to add that directory to your PATH variable. user$ bochs-dlx Checking for bochs binary...ok Checking for DLX linux directory...ok Entering /usr/local/bochs/dlxlinux Running bochs ======================================================================== Bochs x86 Emulator 1.2.1 June 12, 2001 ======================================================================== 00000000000 [ ] looking for configuration in .bochsrc 00000000000 [ ] looking for configuration in bochsrc 00000000000 [ ] looking for configuration in bochsrc.txt 00000000000 [ ] reading configuration from bochsrc.txt 00000000000 [ ] using log file bochsout.txt 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.

If you get the DLX Linux screen, your Bochs installation is working correctly. This documentation will assume that everything is working as expected, then there are some tips at the end in case any step goes wrong. &FIXME; Point to all the files that get installed with the RPM: binaries, BIOSes, DLX linux, HTML docs and man pages, etc.

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 also work. 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 Win32 with Cygwin. 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. All configure options are documented in a later section. One useful configure option is --prefix=directory, which sets the directory in which Bochs will be installed. Among other things, the configure script tries to guess your compiler and a set of compile options that work. 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. The sources are ready to compile.

In the Bochs source directory, there is a series of scripts called .conf.platform. These scripts run configure script for you, with a set of options that appropriate for that platform. On some platforms, configure cannot guess all the right options, so it is necessary to use the shortcut scripts instead of a plain configure command. If a .conf.platform file exists for your platform, you should probably use it. If a shortcut script is "almost right" for you, just edit it and then run it! If you use 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.macosx .conf.win32-vcpp .conf.win32-cygwin .conf.AIX.4.3.1 .conf.beos-x86-R4

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. &FIXME; We should mention what gets installed, and where. /usr/local/bochs/$VERSION/* /usr/local/bin/bochs (and bximage) /usr/man/man1/bochs*.1 (and bximage.1) make install_dlx 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 currently solution to this problem is that the Bochs configure script can 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 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 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 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.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.dsw 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 auxilliary programs bximage.exe and niclist.exe. The workspace compile method is new in version 1.3, so it has not had very long to be tested and tuned. Using workspaces is easy and intuitive, but there is one caveat. The workspaces are not currently integrated with configure. Some configure options such as --enable-debugger need to add additional source files to the Makefile to be compiled, but they do not alter the workspace file. If you add configure options and start having compile problems, try the nmake method (below) instead. These problems should be fixed in future versions. To compile with the debugger enabled, add "--enable-debugger" to the configure line in .conf.win32-vcpp before running it. Then when you have loaded the workspace file, you must add the debug and disasm libraries to the project dependency list. Choose Project:Dependencies and make sure that debug and disasm are checked. 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 is new in version 1.3; before that, nmake was the only way to compile Bochs in VC++. If you are having trouble with the workspace, try the nmake compile instead. 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. A few compiler options are needed, so it is best to use the configure shortcut script called .conf.win32-cygwin. Edit the shortcut script if you want to modify the configure options. Then, to compile in Cygwin, just type: sh .conf.win32-cygwin make These options are known to work in cygwin, so they are enabled in the configure shortcut file: --enable-cdrom --enable-sb16=win

Possibly 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.

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 need to install the compiler and libraries from the development tools CD. It should configure and compile ok if you use the .conf.macosx configure shortcut script. 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. sh .conf.macosx make If you have X windows installed, you should also be able to build Bochs with X windows GUI. To try it, just run configure instead of the .conf.macosx shortcut script.

Kevin Lawton ported Bochs to BeOS. Bernd Korz has taken over the port, and is working on raw cdrom and raw floppy support. It should compile if you configure with --with-beos or use the .conf.beos-x86-R4 script.

Nicholai Benalal created this port to MorphOS running on Amiga. It should compile with ./configure --with-amigaos; make Bryce also made an (untested) .conf.amigaos script that enables FPU and CDROM.

Linux is based on Unix, so it uses the standard compile. Several Linux distributions use the Redhat Package Manager (RPM) to make it easier to install and uninstall software. If you want to build an RPM of Bochs, here are the commands. Edit .conf.linux first if you want to adjust the configure options. su root Password: type root password sh .conf.linux make rpm When this command completes, you will have a source RPM and a binary RPM of Bochs, probably under /usr/src/redhat/RPMS. The output of the make rpm will tell you the exact location of these new files. Instructions for installing an RPM are here.

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 options in the first table choose which GUI library to use. The default is --with-x11 so if you don't include --with-* it will try to compile for X windows. Option Default Comments --with-x11 yes Use X windows user interface. This is the default, so you never actually need to type it. --with-win32-vcpp no Use Win32 GUI/Visual C++ environment. This is for running configure on a platform which supports running configure, so that you may then transfer the configured code over to an MS Win32/Visual C++ environment. See for details. --with-win32 no Use Win32 GUI, but compile with a Win32/gcc environment such as cygwin. For cygwin, see .conf.win32-cygwin for the correct compile options. --with-carbon no Compile for MacOS X with the Carbon GUI. See the .conf.macosx file for the correct MacOS X compile options. --with-amigaos no Compile for Amiga MorphOS. This code is written by Nicholai Benalal. --with-rfb no Use RFB protocol to talk to AT&T's VNC Viewer. 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. RFB mode has been tested in Linux and Win32. --with-beos no Use BeOS GUI. The configure script will run natively on BeOS; use this option when doing so. --with-term no Use text-only gui with curses library. Almost certainly won't work right with the debugger or the control panel. --with-macos no 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. (Hasn't been tested in a long time.) --with-nogui no No native GUI; just use blank stubs. This is if you don't care about having video output, but are just running tests. 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. Option Default Comments --enable-cpu-level={3,4,5,6} 5 Select which CPU level to emulate. Choices are 3,4,5,6 which mean to target 386, 486, Pentium, or Pentium Pro emulation. Pentium Pro support is quite incomplete, so level 5 is the best choice for now. --enable-cdrom no 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, 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={dummy, win, linux} no Enable Sound Blaster emulation. SB16 output is only supported for Windows or Linux. The dummy option means to support an SB16, but don't use an output device. So for example, you might use --enable-sb16=linux. Check out &FIXME; sound.html for more info. --enable-control-panel yes Enables text-mode configuration menus when you first start Bochs. The menus let you read in a bochsrc file, edit some options, and safe the new bochsrc before starting the simulation. Also enables a runtime menu (controlled by a Config button on the Bochs display) which lets you change certain settings during simulation. The control panel was added by Bryce Denney. --enable-new-pit yes Enables Greg Alexander's PIT model, written during Summer 2001. This model was written from scratch to be much more complete than the old Bochs PIT model, which was missing many registers and features. If you disable this option, the old PIT model will be used instead. --enable-slowdown no Enables Greg Alexander's experimental "slowdown timer" which tries to keep the Bochs simulation time in sync with real time. When Bochs is executing many instructions, the slowdown timer will have no effect. When Bochs is idle, or just waiting around for an interrupt, the slowdown timer kicks in to prevent Bochs time from speeding ahead. This should solve problems like, "Why does my screen saver turn on after 30 seconds?" --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. --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 NT/2K Windows support was very recently added by Don Becker, and will not work on Windows 95/98. . When enabled and configured, the NE2000 device model can talk to any computer on the network EXCEPT FOR the local host. --enable-vga yes Use VGA emulation. VGA is the only supported option and since it's the default, you don't need to include this option. --enable-fpu yes If you want to compile bochs to make use of the FPU emulator written by Bill Metzenthen (the one used by the Linux kernel), use this option. --enable-split-hd yes When enabled, this allows a series of partial hard disk image files to be treated as if it was one large file. The .bochsrc specifies the first partial HD image (example win95-1) and then bochs searches for the other partial images in as a sequence (win95-2, win95-3, etc.) and opens them all. Then, it treats the series as if there was a single large file created by "cat win95-1 win95-2 win95-3". This trick works for both diskc and diskd. All files must be a multiple of 512 bytes. --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. Look at the section entitled 'OPTIONAL DEBUGGER SECTION'. &FIXME; add cross references --enable-disasm no 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. You don't need this option. --enable-cpp no Use .cpp as C++ suffix. Renames all the .cc files to .cpp for use with compilers which want that, like MS C++ compilers. Don't use this option unless you know you need it. Option Default Comments --enable-iodebug no 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 section &FIXME; in the Developer's Guide for details. --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..DR8, instruction and data breakpoints etc., then you should use this option. Otherwise don't use it, as it will slow down the emulation. --enable-pci no Enable limited i440FX PCI support. This is not complete. Don't use this option. --enable-port-e9-hack no Writes to port e9 go to console. Unless you know you want this option, you don't. --enable-processors={1,2,3,...,15} 1 By changing to more than 1 processor, you enable 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. Click here &FIXME; for more details on SMP in Bochs. --enable-apic no In an SMP machine, there is an APIC (Advanced Programmable Interrupt Controller) built into each processor and a separate I/O APIC. The APICs are used for inter-processor communication, so they must be enabled for SMP to work. The default is "no" when there is one processor and "yes" when there is more than one processor. Normally, the default is correct and you would never need to type this option. --enable-loader no Support calling external loader from debugger. This is an unsupported option. Don't use it. --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-simid={0, 1} 0 CPU simulator ID. You likely don't need this option. If you are using bochs to cosimulate, that is to run multiple simulators in parallel so that you can compare results and check for divergence, each simulator needs an ID. When you only have one CPU simulator (as usual) the default of 0 is fine. [Kevin wrote: I use this option occasionally to run 2 versions of bochs against each other and check for divergence, to find bugs etc. This option gets broken more than not due to architectural changes, and I usually end of fixing it each time I use it.] --enable-num-sim={1, 2} 1 Number of CPU simulators. The default of 1 is likely what you want, so don't use this option. It is for assigning an ID to the simulator, for cosimulation described above. --enable-time0=n no Start CMOS clock at at time0 of n instead of using time(). You likely don't want this option. When debugging, it is very helpful to have deterministic execution, and the clock is something that can skew determinism. If you supply this option, pass it a value returned by the time(NULL) call, relating to the time you want bochs to start the CMOS clock from. For instance, '--enable-time0=917385580'. If you use this option but don't provide a value, configure uses a default value. Note that the time0 option in .bochsrc will override this value. Without this option, the CMOS clock uses a time0 based on the value of time(NULL), which is probably what you want. --enable-hga-dumps=Nmicroseconds no Copy memory to HGA video buffer every N useconds. A deprecated option, don't use.

&FIXME; what if configure fails? - tar up config.* and send to bochs-testing@tlw.com - 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_system.h, 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.

&FIXME; - bochsrc, BIOS, VGABIOS, VGA font, disk images. - (DONE) table of bochsrc options and what they do - BIOS/VGABIOS, what do they do? - VGA font, how to install it - disk images - where to find one pre-made - make a blank one with bximage - grab one from a real hard disk

Bochs uses a configuration file called a 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, and parses it. Here are a few lines from a sample file: diskc: file="30M.sample", cyl=615, heads=6, spt=17 boot: c 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 section below lists all the supported bochsrc options.

Examples: file=bios/BIOS-bochs-latest, address=0xf0000 You need to load a ROM BIOS into addresses 0xf0000-0xfffff. The 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.

Examples: megs: 32 megs: 128 Set this to the default number of megabytes of memory you want to emulate. The default is 32, since most operating systems won't need more than that.

Examples: vgaromimage: bios/VGABIOS-elpin-2.40 You also need to load a VGA ROM BIOS at 0xC0000. A VGA BIOS file from Elpin Systems, Inc. is provided in the source and binary distributions.

Examples: 2.88M 3.5" Floppy: floppya: 2_88=a:, status=inserted 1.44M 3.5" Floppy: floppya: 1_44=floppya.img, status=inserted 1.2M 5.25" Floppy: floppyb: 1_2=/dev/fd0, status=inserted 720K 3.5" Floppy: floppya: 720k=/usr/local/bochs/images/win95.img, status=inserted 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). You can set the initial status of the media to ejected or inserted. Usually you will want to use inserted. In fact Bryce can't think of any reason to ever write ejected in your bochsrc.

Examples: diskc: file=10M.img, cyl=306, heads=4, spt=17 diskc: file=112M.img, cyl=900, heads=15, spt=17 diskd: file=483.img, cyl=1024, heads=15, spt=63 The diskc/diskd lines tell Bochs what disk image file to use as the constants of the emulated hard drive, and what geometry it should have. Diskc is the first hard drive, and diskd is the second hard drive. At present, using a raw hard drive is NOT SUPPORTED and dangerous to your data. The file should be a disk image file, which must be exactly 512*cyl*heads*spt bytes long. The geometry settings are cylinder (cyl), heads, and sectors per track (spt). If you use bximage to create the image, it will give you the required cyl, head, and spt information. You cannot use both diskd and cdromd together.

Examples: cdromd: dev=/dev/cdrom, status=inserted (Unix only) cdromd: dev=e:, status=inserted (Windows only) cdromd: dev=cdromimage.iso, status=inserted The cdromd line tells Bochs to emulate a CD-ROM device. You cannot have both a diskd and a cdromd, and there is no cdromc option. You cannot use both diskd and cdromd together.

Examples: newharddrivesupport: enabled=1 This setting enables support for large hard disks, better CD recognition, and various other useful functions. You can set it to "enabled=1" (on) or "enabled=0" (off). It is recommended that this setting is left on unless you are having trouble with it.

Examples: boot: a boot: c This defines your boot drive. You can either boot from 'a' or 'c'.

Examples: log: bochs.out log: /dev/tty (unix only) log: /dev/null (unix only) Give the path of the log file you'd like Bochs debug and misc. verbage to be written to. If you really don't want it, make it /dev/null.

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: 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. The sb16 line defines Sound Blaster 16 emulation. 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. This can be a device or just a file if you want to record the midi data. 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. 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 = Only 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. dmatimer: Microseconds per second for a DMA cycle. Make it smaller to fix non-continous sound. 750000 is usually a good value. This needs a reasonably correct setting for IPS (see below).

Examples: vga_update_interval: 250000 Video memory is scanned for updates and screen updated every so many virtual seconds. The default is 300000, about 3Hz. This is generally plenty. Keep in mind that you must tweak the 'ips:' directive 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: 200 Approximate time in microseconds that it takes one character to be transfered from the keyboard to controller over the serial path.

Examples: floppy_command_delay: 50000 Time in microseconds to wait before completing some floppy commands such as read, write, seek, etc., which normally have a delay associated. This was once hardwired to 50000 but now you can adjust it.

Examples: ips: 1000000 Emulated Instructions Per Second. This is the number of IPS that bochs is capable of running on your machine. You can recompile Bochs, using instructions included in config.h (in the source code), to find your workstation's capability. 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.. Speed Machine Typical IPS 650MhzAthlon K-7 with Linux 2.4.x 2 to 2.5400MhzPentium II with Linux 2.0.x 1 to 1.8166Mhz64bit Sparc with Solaris 2.x 0.75200MhzPentium with Linux 2.x 0.5

Examples: mouse: enabled=1 mouse: enabled=0 This option prevents Bochs from creating mouse "events" unless a mouse is enabled. The hardware emulation itself is not disabled by this. You can turn the mouse on by setting enabled to 1, or turn it off by setting enabled to 0. Unless you have a particular reason for enabling the mouse by default, it is recommended that you leave it off.

Examples: private_colormap: enabled=1 Requests that the GUI create and use it's 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.

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, make feature requests What's a panic? How to report it to bug tracker, how to make it non-fatal. Mouse behavior, enabling and disabling Keyboard mapping problems [...] The Bochs community uses two mailing lists to communicate, called bochs-developers 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

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. 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.

Ideas for new sections: - Using two hard disks - How to install Windows 95 - etc.

This was contributed by Greg Alexander in October 2001. 0.) What you need: 1.) An executable version of bochs. See "obtaining a bochs executable" or "compiling the bochs source" 2.) The bximage program, included with bochs 3.) A FreeDOS boot disk, or a boot disk from another OS capable of producing DOS partitions (i.e. a linux install disk.) 4.) (optional) mtools, a program for manipulating DOS disks/images. 1.) Creating an image file. 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 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 file 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: diskc: file="teaching.img", cyl=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. 2.) Partition and format your image file. Option 1: Using FreeDOS (Advantages: Creates a MBR on the partition.) First, you need to edit the .bochsrc file that bochs uses for configuration information. Open the file .bochsrc with a text editor. Remove any lines in the file beginning with "diskc:". Add the "diskc:" line that was displayed when you ran bximage to the .bochsrc file in the same place that you removed the old "diskc:" 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 file to point at the downloaded FreeDOS image and change its status to "status=inserted". Save and close your .bochsrc. Now run bochs. (see: "Running bochs from the command line.") 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 hard drive. 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 (Disadvantages: 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.

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). If anyone wants to write a tutorial, send mail to &devlist; and volunteer.

This section was contributed by Volker Ruppert. It 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. Here is what Volker writes: 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 harddisk 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 harddisk 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.

Bochs can now simulate an SMP machine when you use "--enable-processors=N" 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. It is important to understand that configuring bochs for 4 processors will 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? (Note that only Linux 2.2 has been tested so far.) local APIC on each processor with timer one I/O APIC model implement RDTSC feature (read time stamp counter) modifications to rombios.c to add a data structure called the Intel Multiprocessor Configuration. An SMP-aware operating system probes BIOS memory to find the structure, which contains information about how many processors, their IDs, interrupt sources, etc. What needs to be done to improve SMP support? still needs work on rombios.c to allow you to configure the number of processors in the .bochsrc. Presently you have to choose the number of processors at compile time. 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 SMP systems other than linux 2.2.14 several parts of the APIC model which weren't needed for linux 2.2.14 are not implemented yet and cause a panic. If you boot linux 2.4.3 for example, it says "panic: cluster model addressing not implemented". See bug report #421938 for tips on getting linux 2.4 to boot. (The apic is not the only problem!) 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.

What disk images are available. Installing from scratch. What works Known problems