DOCUMENT ID:  1509-02

SYNOPSIS:     Restoring the multi-boot menu

OS RELEASE:   Any OS

PRODUCT:      Multi-Boot menus

KEYWORDS:     boot menu solaris interactive msdos multi


SYMPTOMS:     

The multi-boot menu for an x86 system is lost, usually after installing
a new version of MS-DOS. 


DESCRIPTION:  

After upgrading MS-DOS, or some other OS on your PC, the multi-OS boot
menu has disappeared and only that OS boots. 


SOLUTION:

                Using MS-DOS to Restore The Boot Menu

If you are using MS-DOS version 6.x, the version of FDISK that ships
with that system can set non-DOS partitions to be bootable by making
them the "active" partition.  If you are using MS-DOS 5.0 or less, the
FDISK for those systems can only make the DOS partition active.  As soon
as you make the partition with the multi-boot control the active
partition, you will see the multi-boot menu again. 

                   Using Solaris to Restore The Boot Menu

With Solaris you can use the installation floppy to boot under the Unix
system.  With Solaris you will be offered the chance to boot from the
CD, network, or hard drive; depending on which boot disk you use.  Do
not select the hard drive, because it still does not have a boot menu
enabled.  Select either your CD or network boot device, whichever is
appropriate. 

Stop the installation as soon as possible and return to a shell prompt. 
Once you have returned to a prompt, run the fdisk program for Solaris
using the -I prompt to go into interactive mode.  From there it is a
simple matter to make the Solaris partition the active one.  This will
enable the Solaris multi-boot menu again. 

                 Using Interactive to Restore The Boot Menu

You can use the installation boot floppy and stop the installation as
soon the system is up. 

You can now use the fdisk program that comes with Interactive to enable
the Interactive partition.  This will enable the Interactive multi-boot
menu. 

                          Using System Commander

This is a program created by V Communications that can allow for the
booting of MS-DOS, Windows '95, Windows NT, OS/2, Solaris, Interactive
Unix, SCO Unix, Linux, Free BSD, and probably some other OSes as well. 

One advantage of this method is that no single OS is in control of the
booting process.  You do need a minimum MS-DOS FAT partition to hold
System Commander, but you do not have to have MS-DOS itself. 

A second advantage for programmers is that you can have multiple
versions of MS-DOS installed.  By placing each version into its own
directory, including the CONFIG.SYS and AUTOEXEC.BAT for that version of
DOS, you can select the version you need at a particular time.  This is
also useful for some games that require an older version of DOS for some
reason, or maybe the Japanese version of DOS versus the English version,
etc. 

A third advantage is that System Commander will "hide" partitions for
you when booting from a particular OS.  This is needed sometimes when
the partition type for one OS looks the same as that for another (Linux
and Solaris are like this).  By hiding the partition, you can prevent a
"foreign" OS from accessing and corrupting a file system. 

                            Using Other OSes

I can't give the exact procedure, but something similar may be possible
for other OSes that provide a multi-boot control, like Linux, OS/2, and
Windows NT to name a few.  Generally, you can start the install
procedure, stop it before it goes too far, and use the disk partitioning
software that came with the OS that provides the multi-boot menu
service. 


DATE APPROVED: 09/05/95