Basic multicore support for DOS demo uncovered

On the Vogon forums, user MarkDastedt posted an interesting bit of source code he discovered on an old company DVD: a very basic, very rudimentary implementation of multicore support for DOS. Another user, dartfrog, took a closer look and had this to say:

Interesting stuff nonetheless. A worker core is running with no interrupt handlers, no page tables, no memory protection, and no OS. That's about as close to bare metal as you can get, meanwhile the other core is still running DOS. Fascinating.

MarkDastedt at the Vogon forums

It's effectively a simple demo, but according to other users in the thread, it fits in neatly with sporadic other attempts to bring some form of SMP or multicore-awareness to DOS. For instance, Michael Chourdakis worked on something similar to this demo for a series of articles now only available on the Wayback Machine. It makes for a cool demo, but moving from this to something robust and usable in DOS is not an easy task.

Still, the possibilities are definitely there, even if you don't implement full, modern SMP or multicore support. You could have specific DOS applications offloading dedicated tasks to different cores, but as others in the same thread note, individual cores are already stupidly powerful for anything DOS can do, making the use case for additional cores rather moot.