On Tue, Dec 27, 2022, 7:31 AM Chris via cctalk <cctalk@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 >
