DOS, XENIX & problems

[root]

First, let me say "thanks" to everyone who responded to my scream for
help in trying to get DOS and XENIX up and running on the same HD.
The many comments were indeed helpful.  Here are some conclusions
I have come to and some possible suggestion for others that might be
faced with a simular situation down the road.

I highy suspect the fact that a huge disk being used was part of the
problem, (650 meg). Under soft formating, the disk had to be split at
the 1024 cyl boundry to keep DOS happy.  That created what the system
sees as 2 hard drive which are actually on the same physical disk.
The type of controller used must have this capibility.  The draw back
is that adding a second HD can not be done without another controller
card.  We used a LARK card - not an endorsement, but it was what we
had.  In this case we were using an EDSI drive/controller.

This is based on XENIX 2.2.3 & 2.3.2 for 286 and 2.3.2 for 386.

The version of DOS plays a part in the dual OS scheme.  Seems as if
XENIX only recognises the partitioning generated by DOS 3.X... and
even then, the DOS partition is limited to 32 meg.  Xenix can't
recognise large partitions in DOS.  (more on this later).
DOS 3.31, aka DOS 3.3+ allows additional partitions to be created, but
again are limited to the 32 meg boundry.  I understand that DISK
MANAGER will allow partitions larger than 32 meg,  I havn't checked it
out yet.  Of course, DOS 4.x allows big partitions, but XENIX won't
recognise them.  And lables the DOS partition as UNKNOWN.  Thereby
preventing dos to be run at the XENIX prompt.  Of course, none of the
dos (XENIX) utilities will work either.

My conclusion has been to create the initial DOS partition using 3.3+;
load XENIX (2.3 - 386 in this case), use Disk Manager to enlarge the
additional partitions needed on drive C:.  Drive D: is used as DOS
4.x.  with it's own autoexec.bat file to swith the system and allow
the use of programs needing that version of DOS.

Now granted, this is an unusual situation as most people using a hard
drive >350 meg generally have the drive dedicated to one Operating
System.  And those who have a dual OS, from what I've been told,
generally dedicate the bulk of the space to XENIX.  I only have 2 meg
for DOS on my 286.  And... that was set up 4 years ago.

Now, The real solution to all this is placed in SCO's lap.  They
are aware that the current fdisk supplied with 2.X XENIX (286 & 386)
as well as the dos routines will not recoginise partitions greater
than 32 meg and/or created by DOS 4.x fdisk.  But after questioning
them about it, they offer no possibility of getting this problem
resolved anytime in the near future.  With more and more users
going to the larger drives, I think they need to get cooking and get
this fixed, because they ain't the only *NIX ball game in town and
their reputation for getting problems solved is slipping greatly.
There are going to be a lot of "unhappy campers" out there using
SCO and not knowing why they are having problems in the dual system
setup.  I can't comment any about the SCO UNIX version. I just don't
know.

OK, SCO, I know you read this Newsgroup, the ball is in your court - 
lets hear your responce.
Scotty
sysop at ozdaltx