[GEM Development] New driver: Sigma 400

[Steve Nickolas]

One e-mail, two replies from me...

On Sun, 21 Oct 2018, John Elliott wrote:

> Slightly complicated by the fact that the source is for MSDOS 2.11 and the 
> MSDOS.SYS is MSDOS 2.00, but it is, after all, only a third of the size of a 
> GEM driver.
>
> Here's a building MSDOS.SYS for 2.00: 
> <http://www.seasip.info/DOS/msdos200.zip>

I dug through the tools I had.

MASM 3 didn't work for me - wound up using 5.10A.  The LINK.EXE from 
Visual Basic for MS-DOS did the trick, and I rolled my own exe2bin (see 
the other post - it came from that tree).

I wonder how hard it would be to revert command.com from version 2.11 to 
2.02.  I have a 2.02 binary that works with MS-DOS 2.0, but the 2.11 
binary displays a corrupt date and time prompt and then locks up (this 
isn't a problem with our builds; a 1983 command.com 2.11 will do that on a 
1983 msdos.sys 2.00).

Of course, it would still require IBM's bootloader and DOS BIOS, until 
these could be replaced.

Of what materials exist from other versions of DOS, I wonder what could be 
used to reconstitute the missing pieces of the 2.11 BIOS?  Maybe one of 
the OAKs out there holds the key...

-uso.