On Sat, 7 Dec 2024 at 08:09, Arrigo Triulzi <arrigo(a)alchemistowl.org> wrote:
On 7 Dec 2024, at 13:34, Henry Bent
<henry.r.bent(a)gmail.com> wrote:
Also interesting; I wonder if the "capability to run multiple MS-DOS
applications under Unix" was shipped in a functional form, and what
relation it might or might not have had to what was running on the AT&T
hardware.
I used to run an 80286 “Taiwan clone” (as we called them in Italy) with
Xenix 286 and, later, its 386 version which was SCO by then (memory a bit
fuzzy on when Xenix became SCO Xenix and the Unix) and I definitely could
run MS-DOS programs on the 386 - you would use the dos command which mapped
drives either to physical drives (i.e. A: was the floppy) or directories
within the filesystem.
It was often used for businesses which had their inventory on MS-DOS
bespoke software but wanted to “multitask” so we had some very dirty code
which would run the DOS program on the serial terminals writing to a
“network” drive which was actually a directory in the Unix filesystem.
Interesting, thank you for the explanation. How was file locking handled
for DOS programs? Did it have some sort of internal call to "share" or was
there a more elegant method?
-Henry