引言

     最近在做操作系统方面的研究，不得不去下一个虚拟机 来用。由于我不使用Windows，所以选择很少了。因为在Linux上，差不多就只有两款好的 虚拟机——Bochs和Qemu。这两个之中，Bochs是用C++编写，能在很多平台上使用，而且不论什么平台， 它都不倚赖主机的指令系统，总是模拟x86。所以我选择了Bochs。但是，我惊讶地发现 关于如何在Linux上使用Bochs的资料很少。Bochs自带的文档中讲得也不很明确，而且还 是英文的。所以我写了这篇文章。

安装

     到Bochs的主页： http://bochs.sourceforge.net 上下载最新的Bochs RPM安装包。（写这篇文章时，最新的版本是2.2.1。）以root的身份安装：

#rpm -ivh bochs-2.2.1-1.i586.rpm

$ bochs-dlx
---------------------------------------------------------------
             DLX Linux Demo, for Bochs x86 Emulator
---------------------------------------------------------------
Checking for bochs binary...ok
Checking for DLX linux directory...ok
Checking for /usr/bin/gzip...ok
Checking for /home/wangcong/.bochsdlx directory...ok
Entering /home/wangcong/.bochsdlx
Running bochs
00000000000i[APIC?] local apic in initializing
========================================================================
                         Bochs x86 Emulator 2.2.1
                 Build from CVS snapshot on July 8, 2005
========================================================================
00000000000i[ ] LTDL_LIBRARY_PATH not set. using compile time default '/usr/lib/bochs/plugins'
00000000000i[ ] BXSHARE not set. using compile time default '/usr/share/bochs'
00000000000i[ ] reading configuration from bochsrc.txt
00000000000i[ ] lt_dlhandle is 0x8bac490
00000000000i[PLGIN] loaded plugin libbx_x.la
00000000000i[ ] installing x module as the Bochs GUI
00000000000i[ ] using log file bochsout.txt

使用

     下面是一些重要的文件：

/usr/bin/bochs	Bochs启动程序
/usr/bin/bximage	Bochs带的制作磁盘镜像文件的工具
/usr/bin/bxcommit	把redolog放进flat磁盘镜像文件中去的交互工具
/usr/share/doc/bochs/bochsrc-sample.txt	Bochs配置文件的例子
/usr/share/bochs/BIOS-bochs-*	ROM BIOS镜像文件
/usr/share/bochs/VGABIOS-*	与VGA BIOS镜像文件相关的文件
/usr/bin/bochs-dlx	启动Bochs中DLX linux的程序
/usr/share/bochs/dlxlinux/	DLX Linux的目录，包含它的磁盘镜像文件和配置文件
/usr/share/bochs/keymaps/*.map	X11和SDL的keymap列表

     命令bohcs可以接受4个参数：-q　加载配置文件后跳过开始菜单；-f configfile 识别指定的配制文件；-n　不加载配置文件；-h 打印帮助信息；-qf configfile 相当于同时使用-q和-f两个选项。使用Bochs，你必须有一个配置文件，或者你通 过-f参数指定，或者让Bochs自己搜索。配置文件的作用是告诉Bochs到哪里寻找镜像 文件，模拟层如何工作等。Bochs搜索配置文件的顺序是：

1. 
   

2. bochsrc 在当前目录中

3. 
   

4. .bochsrc 在用户的主目录中

5. bochsrc 在 /etc 目录中

###############################################################
# bochsrc.txt file for DLX Linux disk image.
###############################################################

# how much memory the emulated machine will have
megs: 32

# filename of ROM images
romimage: file=$BXSHARE/BIOS-bochs-latest, address=0xf0000
vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest

# what disk images will be used
floppya: 1_44=floppya.img, status=inserted
floppyb: 1_44=floppyb.img, status=inserted

# hard disk
ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
ata0-master: type=disk, path="hd10meg.img", cylinders=306, heads=4, spt=17

# choose the boot disk.
boot: c

# default config interface is textconfig.
#config_interface: textconfig
#config_interface: wx

#display_library: x
# other choices: win32 sdl wx carbon amigaos beos macintosh nogui rfb term svga

# where do we send log messages?
log: bochsout.txt

# disable the mouse, since DLX is text only
mouse: enabled=0

# enable key mapping, using US layout as default.
#
# NOTE: In Bochs 1.4, keyboard mapping is only 100% implemented on X windows.
# However, the key mapping tables are used in the paste function, so
# in the DLX Linux example I'm enabling keyboard_mapping so that paste
# will work. Cut&Paste is currently implemented on win32 and X windows only.

keyboard_mapping: enabled=1, map=$BXSHARE/keymaps/x11-pc-us.map
#keyboard_mapping: enabled=1, map=$BXSHARE/keymaps/x11-pc-fr.map
#keyboard_mapping: enabled=1, map=$BXSHARE/keymaps/x11-pc-de.map
#keyboard_mapping: enabled=1, map=$BXSHARE/keymaps/x11-pc-es.map

megs: 32

romimage: file=$BXSHARE/BIOS-bochs-latest, address=0xf0000

floppya: 1_44=floppya.img, status=inserted
floppyb: 1_44=floppyb.img, status=inserted

ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
ata0-master: type=disk, path="hd10meg.img", cylinders=306, heads=4, spt=17

boot: c

boot: cdrom, floppy, disk

mouse: enabled=0

keyboard_mapping: enabled=1, map=$BXSHARE/keymaps/x11-pc-us.map

制作磁盘镜像

     bximage是Bochs自带的制作磁盘镜像的工具，具有 良好的交互性，使用很方便。运行bximage，你会看到：

========================================================================
                                 bximage
                   Disk Image Creation Tool for Bochs
       $Id: bximage.c,v 1.25.2.1 2005/07/06 20:40:00 vruppert Exp $
========================================================================

Do you want to create a floppy disk image or a hard disk image?
Please type hd or fd. [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]

I will create a 'flat' hard disk image with
   cyl=2
   heads=16
   sectors per track=63
   total sectors=2016
   total size=0.98 megabytes

What should I name the image?
[c.img]

Writing: [] Done.

I wrote 1032192 bytes to hd.img.

The following line should appear in your bochsrc:
   ata0-master: type=disk, path="hd.img", mode=flat, cylinders=2, heads=16, spt=63

     另外Bochs还有强大的调试功能，详细请参阅用户 手册第8章。Bochs主页上还有一些做好的系统镜像，比如：OpenBSD，FreeDOS等。 不妨下载一个来试试。 Bochs的确是一款优秀的工具，我推荐给每一位做操作系统研究的朋友。