27 Dec
2022
27 Dec
'22
3:11 p.m.
On Tue, Dec 27, 2022, 7:31 AM Chris via cctalk <cctalk(a)classiccmp.org
wrote:
Apparently Northstar's dos is yet another amended
version of ms-dos. I
suppose it was supplied for basic tasks, as it couldn't possibly provide
all the features supplied by Netware. So whereas this may not be as
difficult as I thought, there are still significant hurdles. The floppy
drive's transfer rate is 250kbits/s. That probably isn't significant.
The Dimension machine you have is PC compatible, more or less, according to
the various places I found last night.
In that era, MS-DOS provided part of the solution. It did the program
loading and filesystem services. The ROMs provided the rest. The difference
between the different MS-DOS versions for things like the Rainbow, Victor,
Tandy etc were all in the IO.SYS file that handled the device drivers for
the machines in question. It also handled the different floppy formats and
often times hid the second stage boot loader in funky, machine specific
places.
In that era too a lot of software was in the ROMs and that's where 90-95%
of the non-timing incompatibility was: The ROM routines weren't complete in
the early clones (of which the Dimension was). And that was before there
was one video card standard, so going direct to video memory was tricky
(possible, and a lot of people did it, but there were many articles about
how to probe for what's there, how to structure your code to make it less
hard but still fast, etc).
I suspect there is more there than you think, but probing it, or recreating
the boot disks may require some unique to the machine fiddling...
Warner