SCSI cards

From: Feldman, Robert <Robert_Feldman_at_jdedwards.com>
Date: Wed Feb 26 10:07:46 2003

IBM PC-DOS 3.30 could support 4 partitions, one Primary and 3 Extended. The
primary partition is limited to 32MB. Extended partitions can be divided
into a number of logical drives, each limited to 32MB. What limits the
number of ligical drives (beyond the disk capacity) is the availability of
drive letters: the primary partition is assigned to Drive C: (unless you
have more than two floppy drives), and the logical drives get letters from
D: through Z:. By my calculations, with all 24 hard drive letters assigned,
the limit is 768MB.

-----Original Message-----
From: Ethan Dicks [mailto:erd_6502_at_yahoo.com]
Sent: Wednesday, February 26, 2003 8:39 AM
To: cctalk_at_classiccmp.org
Subject: Re: SCSI cards


--- Geoff Reed <geoffr_at_zipcon.net> wrote:
> I'm pretty sure that msdos 3.11 supported multiple partitions :)

It does. I have a PS/2 Model 30 (ISA) with a 50MB RLL drive replacing
the original IBM IDE-ish drive. Two partitions under MS-DOS 3.11, one
30MB, one 20MB.

The problem is that there is a small number of partitions possible
(I don't recall if FDISK works the same way under 3.x as it did later),
certainly no more than 4 primary partitions. DOS 4.x came out (as bad
as it was) before 200MB drives were common. By the time "everybody"
was buying "larger" drives, DOS 5.0 was out, solving several problems
with historical baggage.

> also if I had a SCSI controller in the beastie I'd probably go on the
> quest for rainbow Venix :)

Hmm... I would expect you'd need a Venix driver for it.

If you _really_ wanted a challenge, you could port Minix to the Rainbow.
Sources are available. Writing a Minix driver for the FDC might be
interesting (not sure how much suitable documentation exists).

-ethan
Received on Wed Feb 26 2003 - 10:07:46 GMT