Path: utzoo!utgpu!watserv1!watmath!att!att!emory!swrinde!zaphod.mps.ohio-state.edu!rpi!batcomputer!munnari.oz.au!csource!david
From: david@csource.oz.au (david nugent)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: MS-DOS 3.3 or 4.01?
Message-ID: <759@csource.oz.au>
Date: 19 Nov 90 03:13:24 GMT
References: <71077@iuvax.cs.indiana.edu> <15090019@hpspcoi.HP.COM>
Organization: Unique Computing Pty Ltd, Melb, Aust.
Lines: 27

In <15090019@hpspcoi.HP.COM> dlow@hpspcoi.HP.COM (Danny Low) writes:

> When 3.3 was the latest and greatest DOS version, several PC makers
> added large volume support to 3.3 and typically relabelled it 3.31.
> The large volume was implemented through a special disk driver and
> FDISK program supplied by the maker. The problem with this scheme 
> is there was no standard so large hard disks partitions created this way 
> were incompatible. I know of some cases where an attempt to upgrade
> from "3.31" to 4.01 required trashing the hard disk to make 4.01
> recognize the hard disk. In addition some programs did not run with
> the large partitions and special disk driver.


The scheme Compaq used in their DOS 3.31 is identical to that used by
MS-DOS 4.0 and upwards.  No special driver required.  FDISK from 4.01
recognises the partition correctly, and you can upgrade from Compaq
DOS 3.31 to DOS 4.x with no problems at all.

I can't speak for any other DOS 3.31 - I've never seen any other than
the one supplied with a Compaq 386/20 I used to use. I also noted that
the changes made to calling conventions in the direct disk read/write
functions (INT 25H & 26H) are identical to those used by DOS 4.x.

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