CP/M-386 – CP/M for 386 protected mode, derived from CP/M‑68K

I worked at Digital Research from 1984 to 1990. CP/M-68K was the first operating system I used there, but only for a brief period. It's unfortunate that the source for FlexOS is not available; it would be a better choice for a hobby project like this. It was a protected mode OS for the 286 that had a real-time kernel, TCP/IP stack, DOS compatibility box, and more. It was a clean break from CP/M. IBM used it in their point-of-sale terminals for quite a few years, and I worked on porting it to 32-bit architectures like the NEC V60. It died after Novell bought DRI, aside from its use inside IBM.

One of my first jobs, back in the 1980s, was a project for a government department that the supplier (Wang Computers) had bet on MS-DOS being multi-process.

Of course, it wasn't but there was MP/M-86/CCP/M/CDOS/DR-DOS which allowed you to have 4 "users"/virtual TTYs.

So we ended up using that along with some tweaks to the software (including an IBM 3270 emulator, MS-Word/Excel (the DOS versions), and a custom software app) that ended up getting deployed to a few hundred government offices.

Mostly worked except some of the software really didn't like the fact that it was being swapped out of keyboard/screen access.

I'm pretty sure CP/M 86 was already a thing. I believe there was even Concurrent CP/M 86, which let you run up to 4 (or more?) virtual sessions concurrently. Light years ahead of MS-DOS but nobody wanted it, so DRI dumbed it down and added MS-DOS compatibility and re-released as DR-DOS (still superior to MS-DOS though).

Just as some off-the-top history, MS-DOS was clearly obsolete, but it hung around for like 10 years too long because people couldn't quit it. It was a DOSSY DOS world.

"Protected Mode DOS" went through the IBM/MS gristmill and became OS/2, which was a compromised product in a lot of ways. Then Windows (still mostly a DOS program) got a little traction, and Microsoft had hired Dave Cutler to write a real OS. And David overthrew Goliath and the rest is history. On topic, nobody really wanted protected-mode DOS or CP/M etc.

CP/M - because pip just makes more sense than copy.

CP/M‑386 is currently in the very early development stages.

    Full 32‑bit protected mode implementation with Ring‑3 TPA.
    Bootable via 3.5" 1.44MB floppy disk MBR or GRUB Multiboot kernel.
    Supports VGA text (0xB8000) and/or COM1 serial (9600/N/8/1, 0x3F8) consoles.
    No floppy/hard disk/CD/USB/network/sound/other drivers (yet).

First project of this kind on here in a long while that isn't complete AI slop. Well done, really happy to see some people still doing this!

>"Compatible with 386 (and later systems) with 2MB (or more) memory."

Looks good!

An order of magnitude (or two!) less code complexity and less memory hungry than most of 2026's bloated Operating Systems...

Well done!

Does it support flat memory model or its banked like DOS ?

Now if I can find those 8” wordstar floppies.

ingesting....but not was like "Star trek project" something like this. DR-DOS evolved from CP/M-86 and they added. And "Star Trek" added to DR DOS a multitasker named "Vladivar" (and a port of System 7 GUI). If I remember it correctly, there is these multitasker in DR-DOS 7 that allow pre-emptive tasking in 32 bits protected mode.