Early MS-DOS MCB notes

All aspects of programming on the Commander X16.
Post Reply
voidstar
Posts: 497
Joined: Thu Apr 15, 2021 8:05 am

Early MS-DOS MCB notes

Post by voidstar »

Wanted to note down the following reference, a Dr Dobbs article from 1988 describing MS-DOS 2.0's MCB (memory control blocks). Ignoring the 80286 and later MS-DOS's protected mode stuff, this earlier MS-DOS 2.0 stuff can give insight on how they managed conventional memory while still having 64KB segments.

https://www.drdobbs.com/architecture-an ... /184408026


Note also that a variant of the 6809 is being made available to the Foenix system:
https://c256foenix.com/product/fnx6809/?v=7516fd43adaa
And that variant will support things like running NitrOS9 (multi-tasking OS with GUI) on the Foenix. I've always been a fan of the 6809, and I suspect a similar thing could work on the X16.

Before considering anything like a high-level language on-system (like C), some kind of OS (or at least a memory management system) I think quickly becomes essential. You can make "tiny" versions of those compilers, but those will remain essentially 64K limited. See how the PowerC experience went on the C64:
https://www.youtube.com/watch?v=GRMApkIHqKA

CP/M never quite tackled the "64K barrier" either.
Post Reply