So, I came across this project from some random google search on Watcom the other day. Â Simply put it is a MS-DOS API that is supported in both a 16bit real mode operating system, and a 32bit operating system. Â It is quite sparse but very interesting all the same. Â Using the ancient EMX port of GCC you can build 32bit (simple) programs, and run them in the 32bit DOS like Operating System. Â What makes this even more interesting is that there is a port to the IBM 370, and 390 based hardware, along with the fictional 380.
You can download my diskimages, (VMDK & floppy disk) that I’ve used with Qemu to build & boot PDOS both 16bit and 32bit.
The included libc & system libraries are lacking compared to real MS-DOS, but this is public domain code, and with a bit of TLC it could be made into something much more.