25 May
2020
25 May
'20
11 a.m.
On Mon, 25 May 2020 at 05:30, Fred Cisin via cctalk
<cctalk at classiccmp.org> wrote:
I played briefly with Xenix on an XT (or MAYBE an AT) on a 15MB? drive
partition. MS-DOS was a better match for that hardware.
Never tried Xenix on an XT, but it was the 2nd OS on my PC-AT in my
first ever job. That machine was very limited (512 KB RAM, 20 + 15 MB
ST-506 disks), but on a well-specced 286, it was quite a decent little
Unix. It could properly use an 80286 and up to 16 MB of RAM, something
DOS in the 286 era couldn't do -- MS-DOS 3.3 did not even come with a
disk cache. (Not counting FILES=20 BUFFERS=20 in CONFIG.SYS!)
IBMs came with an installable driver called, I think, IBMCACHE.SYS.
This used extended RAM (above 1MB) as a hard disk cache, without XMS
or HIMEM.SYS or any of that. I played with it and was amazed by the
results. I started enabling it by default on customers' machines. Most
were happy but some had the habit of just turning off -- DOS didn't
really have a shutdown routine. Some, I could train to press
Ctrl-Alt-Del before turning off. Some I couldn't, so I had to disable
the disk cache.
But for those that could learn and adapt, it made DOS _much_ faster,
and on a 1MB PS/2 Model 50 or 60, it was about the only thing you
could do with the extra 386 KB of RAM before MS-DOS 5 came out.
So the fact that Xenix could use 4 MB or 8 MB in a 286 seemed like wizardry.
OS/2 (Gordon Letwin at Microsoft) was a substantial
step up for MS-DOS.
Once they added "Windows For Os/2"/"Presentation Manager", . . .
BUT, then NT was not a direct transition from OS/2.
And, around 1986? IBM started pushing OS/2 with PS/2 (had they bought OS/2
from Microsoft by then?)
No, not yet.
OS/2 1.0: 1987. Text-only.
OS/2 1.1: 1988. Finally got the PM GUI.
OS/2 1.2: 1989. Started to be a bit usable.
OS/2 1.3: 1990. Same year as Windows 3.0, which spelled its doom.
OS/2 2: 1992. 1 year before Windows NT 3.1. First IBM-only version,
first 386 version.
AFAIK IBM never _bought_ OS/2. MS walked away from the co-development
deal after Windows 3.0 was a huge hit -- 3 million copies in 1990
alone.
OS/2 2 was the 386 version. OS/2 3 was to be a portable version. There
was next to nothing written, but MS commissioned a line of Intel i860
RISC boxes (codenamed N-10) to prototype it on. When they hired Dave
Cutler & team in 1988, that was the product he was given to salvage.
It became OS/2 NT which became Windows NT.
--
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