booting DOS on ISC+SCO, and DOS filesys handling (long-ish)

[john.urban]

In article <1991Apr27.053546.1461 at rushpc> jjr at rushpc.UUCP (John J. Rushford Jr) writes:
>In article <1991Apr24.074220.17639 at jet.uucp> cm at jet.uucp (colin manning) writes:
>>
>>Anyway, I'd be interested in information on any of the following. I'll 
>>post a summary in due course if there's sufficient interest.
>>
>>1. Is it possible to have an easy way of selecting between booting DOS
>>   or Unix on an ISC system, without having to remember to use fdisk 
>>   every time to change the active partition ? Ideally the source to 
>>   a boot program that could be put on a primary DOS partition would
>>   be nice (like the one I use with SCO).
>>
>I'd be interested in the answer to this for AT&T SVR3.2 also.  I'm not too
>keen on using 'fdisk' to switch active partitions anymore.  Recently I
>used DOS 'fdisk' to switch the active partition from DOS to UNIX.  After
>re-booting I found that 30,000 blocks of free space had disappeared from
>the root filesystem.  I'm not positive but, I suspect that DOS 'fdisk'
>had something to do with it.  I could not fix it using 'fsck'.  I poked
>around in the superblock with 'fsdb' but found nothing.  I ended up 
>reformating the disk and loading from backups.
>-- 
>

AT&T UNIX System V/386 Release 3.2 Version 2.2 has a RAS add-on (Remote
Administration something- or- some add-on like this).  It has an altboot
executable which toggles your boot partiton of your hard disk.

Where as AT&T UNIX System V/386 Release 4.0 has 'altboot' built in to the
code OS.

When you see the prompt:  Booting the UNIX System ...
just press the space bar and type in: altboot and you'll boot from your MS-DOS
partition instead of the UNIX partition.

Sincerely,

John Urban
att!garage!jbu