Compiling and Installing Bochs


Getting current source code

Source code for Bochs, is available from the Bochs home page at bochs.sourceforge.net. You can download the most recent release, or use CVS to check out the latest sources. The releases are the most likely to compile and run without modification, but if you want the very newest features try CVS instead.

Compiling source code

All releases are gzip'd tar files. That means the whole Bochs source code directory has been consolidated into one file using the Unix command 'tar', then compressed to save space with GNU 'gzip'. To extract the source code, you'll need both 'tar' and 'gzip/gunzip'. All files are contained within one subdirectory named 'bochs-YYMMDDv'. 
    cd /path/parent-directory
    gzip -dc bochs-YYMMDDv.tar.gz | tar -xvf -
    cd bochs-YYMMDDv
Before compiling, you'll need to run the configure script, which will configure source code to run on your system, and with your chosen options. There are many options to 'configure', and you probably don't need any of them. For example, if you run BeOS, specify '--with-beos' to configure. To see a complete list: 
    unix-> ./configure --help
For more complete documentation of options available to configure, click on this link.

You will also need to set environment variables to tell configure what compiler and options to use. Check out this link.   It's the same as the one above.

Now run configure, be it manually or by way of a script file. 

    unix-> ./configure
       -or-
    unix-> ./.conf.x86

If the configure script bombs, check 'config.log'. Specifically, look for errors returned by the compiler. You may have options incompatible with your compiler. See the link on setting the environment variables above.

Assuming at this point all went well with the configure command, edit the file 'config.h', which was generated by ./configure. Look for the USER CONFIGURABLE OPTIONS section. Each parameter available for editing is documented.  Generally the defaults are fine for typical users. Please read about each parameter and edit carefully. NOTE: This file is generated, and will be deleted if you run 'make dist-clean'.

You may now compile the source. 

    unix-> make

There are separate instructions for compiling in Windows.

Setting up environment before running

In text mode, Bochs requires your X server to have access to the VGA font. If you don't already have it, you must install it from one of the font files in bochs-yymmdd/font.

There are two options; you may install the VGA font in a global place, or in a local directory. You may need to install it locally if you don't have root access. If the VGA font is not installed properly, you will get the error, "Could not open vga font".

Option 1: installing VGA font in global font directory 


   # NOTE1: Make sure your DISPLAY variable points to local machine.
   # NOTE2: These steps require root privileges.
   # NOTE3: Your X11 fonts path will vary on different systems. For example:
   #        Solaris 2.x /usr/openwin/lib/X11/fonts
   #        Linux       /usr/lib/X11/fonts/
   root-> cp font/vga.pcf font-path-here/misc
   root-> compress font-path-here/misc/vga.pcf
   root-> mkfontdir font-path-here/misc
   root-> xset fp rehash
   root-> /etc/rc.d/init.d/xfs restart     (Restart your X font server)
The command to restart the X font server is given for Redhat systems, but it will vary between different machines, and might not even be necessary at all. If you cannot figure out how to restart your font server, you can just reboot.

Option 2: installing VGA font in local font directory 

   # NOTE1: Make sure your DISPLAY variable points to local machine.
   # NOTE2: The "xset" command needs to be run for each X session.
   user-> mkfontdir bochs-YYMMDD/font
   user-> xset fp+ [full-path]/bochs-YYMMDD/font
Hard Drive Image File: Bochs emulates a hard drive by using a large Unix file, which you must create. The size of the hard drive is dependent upon the number of cylinders, heads, and sectors-per-track that you would like to emulate. Here are some examples of possible drive geometries:

Size Cylinders Heads Sectors/Track Sectors Total
10MB 306 4 17 20808
20MB 615 4 17 41820
30MB 615 6 17 62730
46MB 940 6 17 95880
62MB 940 8 17 127840
112MB 900 15 17 229500
126MB 256 16 63 258048
483MB 1024 15 63 967680
504MB 1024 16 63 1032192
640MB 1300 16 63 1310400
886MB 1800 16 63 1814400
1280MB 2600 16 63 2620800
2215MB 4500 16 63 4536000
3495MB 7100 16 63 7156800
5020MB 10200 16 63 10281600
7088MB 14400 16 63 14515200
10041MB 20400 16 63 20563200
12206MB 24800 16 63 24998400
16045MB 32600 16 63 32860800
20672MB 42000 16 63 42336000
25003MB 50800 16 63 51206400
29974MB 60900 16 63 61387200
32238MB 65500 16 63 66024000

For hard disk sizes larger than 528MB, be sure that newharddrivesupport is enabled. This will be the compiled default in a future release, but for now your .bochsrc still needs the line "newharddrivesupport: enabled=1" in order to support >1024 cylinders.

Pick the size of the hard drive you want to emulate, and create a blank file according to the parameters in the table. If you have the 'dd' command, you can use it to create the file. Keeping in mind that there are 512 bytes in a sector, just use the number of "Sectors Total" from the table as the 'count=' option to dd, and tell dd to use a block size ('bs=') the same as a disk sector size (512). For example, for a 112MB drive, there are 229500 (900*15*17) sectors. 

    unix-> dd if=/dev/zero of=112M bs=512 count=229500
Floppy Disk Image File: Bochs emulates a floppy drive/disk using either a Unix file, or a real floppy drive Unix device. To use either, you will need an entry in your '.bochsrc' file pointing to the regular or device file. Use the 'floppya:' and 'floppyb:' directives. If you are starting out, you will need to make a copy of an existing bootable floppy. Otherwise, you may create a blank image file, if you intend on formatting it using the OS you boot within Bochs.

Size Cylinders Heads Sectors/Track Sectors Total
0.720MB 80 2 9 1440
1.2MB 80 2 15 2400
1.44MB 80 2 18 2880
1.680MB 80 2 21 3360


To create a blank floppy image file, you can use the same concept as above for creating blank hard disk image files. For example, to create a blank 1.44MB floppy image file: 
    unix-> dd if=/dev/zero of=1.44M bs=512 count=2880
To create a copy of an existing floppy disk, granted you have a floppy disk drive on your workstation, you can use one of the following commands, where '/dev/fd0' would be the path to your floppy drive device name.

NOTE: If your system uses a form of volume management to automount your floppy drive, you may have to tell it you popped in a new floppy, and use an alternative device name to access it. 

    # Linux, direct use of floppy drive using 'dd'
    unix-> dd if=/dev/fd0 ibs=512 of=1.44M

        --or--

    # Linux, direct use of floppy drive using 'cp'
    unix-> cp /dev/fd0 1.44M

        --or--

    # With Volume Management handling floppy drive
    Solaris 2.x-> volcheck
    Solaris 2.x-> dd if=/vol/dev/aliases/floppy0 ibs=512 of=1.44M

Bochsrc file options

There are many options which you can change, to alter the behaviour of bochs, enable features, etc. You can set values for these options in a file called ".bochsrc". There should be a reference file with this name, that comes with the source code distribution. As, it's easier to maintain documenting possible commands in the file itself, look in the reference file for more info.

Search Order:

Note: These options are overridden by any command line options you provide

Bochs command line options

You may now pass all options available in the ".bochsrc" file, to bochs on the command line. Syntax for command line options is now identical to directives in ".bocshrc". Old command line options, such as -bootC are no longer valid. Bochs expects that each option is passed as a single argument, so if you need to use spaces, surround the option in quotes. For example: 
  bochs boot:c
  bochs "boot: c"  "diskc: file=../10M.vga, cyl=306, heads=4, spt=17"
  bochs romimage:/tmp/someimage
Note: Look in the reference ".bochsrc" for syntax

Installing an OS (DOS/Win'95/Minix/Linux) within Bochs

The goal of Bochs is to emulate the components of a basic PC (CPU, BIOS, disk drive, floppy, keyboard, VGA, and other chipsets) well enough to allow for multiple Operating Systems to run within the emulator. So far, Bochs has been successful in running several OS's at one time or the other. Follow the link of your choice to learn how to install the OS of your interest.

X11 Keyboard Hacks 

  NOTE: your backspace key may not work properly.  You may have to
        source the file 'misc/xmods' in the main distribution directory.
        I need to look at this problem a little more.
        Using Ctrl-h always seems to work for me.