Appendix 4: Multiple OS Installation

There are different ways that more than one Operating System can reside on the same machine. DOS and Windows can easily reside on the same machine with Linux, and each can be booted at the choice of the operator. Windows 95/98 is a little bit trickier since it demands its own boot manager. Installing Windows 95/98 after installing Linux will result in LILO getting ``bumped off'' the system. Installing Linux AFTER Windows 95/98 will work. You will need to configure your Linux system to be able to boot Windows 95/98 with LILO however.

LILO can be used as long as there is a Linux partition on the first physical drive. With a modified boot record and LILO, the system can be made to boot either Linux or DOS/Windows 95/98. There are other boot loaders available for Intel machines. Most of these can be used to boot a variety of operating systems.

The more versatile method of installation uses the DOS program loadlin.exe. This software can boot a kernel image from a DOS partition and mount any partition on the system as the root partition for that kernel. For automatic operation, the best method is to use the config.sys menu system in DOS to offer the choices of the different OS available on the machine. Then autoexec.bat can determine whether to go ahead and boot DOS or run loadlin and boot Linux. The following example should clarify this process:

config.sys:
[Menu]
menuitem=NewLinux, Linux 2.0.30
menuitem=OldLinux, Linux 2.0.27
menuitem=DOS
[DOS]
DEVICE=C:$\backslash$DOS$\backslash$SETVER.EXE
DEVICE=C:$\backslash$DOS$\backslash$HIMEM.SYS
DOS=HIGH
FILES=30
STACKS=9,256
[NewLinux]
[OldLinux]
autoexec.bat:
cd $\backslash$boot$\backslash$linux
goto %config%
:DOS
cd $\backslash$
C:$\backslash$DOS$\backslash$SMARTDRV.EXE
@ECHO OFF
PROMPT $p$g
PATH C:$\backslash$WINDOWS;C:$\backslash$DOS
SET TEMP=C:$\backslash$DOS
goto End
:NewLinux
loadlinx vmlinuz2 root=/dev/hdb3
goto End
:OldLinux
loadlinx vmlinuz root=/dev/hdb3
goto End
:End

Note: This system allows the root file system to reside on another area besides the first device on the machine.

This process will work for Windows 95/98 as well as DOS/Windows and OS/2.