From: lasner@watsun.cc.columbia.edu (Charles Lasner)
Subject: Re: Unix Roots of DOS?
Reply-To: lasner@watsun.cc.columbia.edu (Charles Lasner)
Organization: Columbia University
Date: Wed, 22 Jul 1992 16:35:39 GMT

In article <cline.711789582@ebony.cs.scarolina.edu> cline@cs.scarolina.edu (Ernest Cline) writes:
>lasner@watsun.cc.columbia.edu (Charles Lasner) writes:
>
>> MS-DOS 4.01 was released several times.  The version where all files are
>> dated about April, 1989 is stable and functional.  I even use it today
>> sometimes.
>
>ARRGH!!!
>Number 1 reason I use Macs instead of DOS/Windows
>Most vendors are not afraid to admit that there was bug, so when they do a bug
>fix, they change the version number. Makes it much easier to determine which
>is latest version, and which is not.

It's worse than you imagine!

DOS 3.3 was implemented by OEM's who went to Microsoft and had specific
modifcations made generally not because their clone hardware was different,
but rather to attempt to give them a "signature" look in some ultimately
nonsensical way.  A few distinguished themselves with some add-ons, most
of which can run on competitor's machines, so ultimately this reduces to
the verbiage in the copyright notice of COMMAND.COM and/or the VER command.
There are even exceptions to this such as Zenith and NEC whose systems aren't
even DOS 3.3 file-system compatible, because they attempted to "stretch" the
file-system block size as a bandaid to the 32M/partition problem.  (At least
Compaq's version calls itself 3.31, not 3.30 when attempting this!)
So, in essence, when you happen upon a 3.3 system, wading beneath all of
the fluff is the base system generally the same for each vendor.  Of course
they all got different patch levels because they "went to the well" only
once.

When DOS 4.01 was released after IBM got DOS 4.00 and all the bugs, Microsoft
gradually got most of the bugs out.  Each OEM version was different, even
though most of them were totally generic, including nothing other than
mentioning Microsoft in the copyright notices.  Also, Microsoft sold this
system themselves unbundled.  I think the earliest appearance was from
Phoenix, the BIOS company, which doesn't even have a computer.  Note that
all copies are marked "to be sold with a computer system only".  I believe
there were some problems between Phoenix and Microsoft on this issue.  In
any case, there were at least two versions of Phoenix's incarnations of
DOS 4.01.  Some of these releases contained GWBASIC and the manual for it, 
while others didn't.  Most notably, Microsoft's release lacked the BASIC.
Eventually, the best way to obtain DOS 4.01 was to purchase Chinese vendor's
copies legally reprinted in Taiwan from companies such as EMPaC or MINTA
which are Taiwanese clone software suppliers with direct ties to Microsoft.
Purchase of a clone at the wholesale distributor's level (or the parts) is
sufficient to qualify the buyer to purchase the software kit, which is how
I personally did it.  (I assemble and sell clones as an OEM; bundling DOS
4.01 is a normal thing to do at that time.)

So, by switching vendors sufficiently, DOS 4.01 just "happens" to get
upgraded.  I never saw any files dated later than April 17, 1989 at 12:00.
Incidentally, some of the files had this date, yet were identical to some
files on other releases with earlier dates.  One version had all files
released at precisely the same second in time; about 20% were actually patched
beyond equivalent files in other releases with earlier dates; the rest were
identical except for the artifically raised release dates.  At least I
never found files that had newer release dates that were ever older than
the corresponding files with older dates!

(BTW, Windows ain't as bad.  There is Windows 3.00 and 3.00a, and 3.1.)

So, if you want a stable version of MS-DOS 4.01, you have to find a system
where all of the files are from April, 1989, or else you run the "risk" of
dealing with a system with a problem that was fixed for someone else, but
not for you! (isn't that a George Harrison song?)

cjl