You probably don't remember this project, but Microsoft's MS-DOS operating system, which dominated the IBM PC market in the 80s, faced some competition, such as a multi-user MS-DOS 5 clone called PC-MOS/386, created in 1987. This operating system could run native MS-DOS applications using the protected mode of Intel's 386 microprocessors and compatible chips. Quite an advancement at the time…
PC-MOS/386 emerged as an evolution of PC-MOS and was optimized, as its name indicates, for the 80386 microprocessors, written in assembly language and also in C, capable of running Microsoft operating system software and being bootable from a 3.5″ floppy disk from which the system image was loaded, although nowadays it comes with CD-ROM drivers and some other new features.
Well, it's now known that Roeland Jansen, one of its developers, will continue with the open-source project . You can find more information about this operating system and its development on the project's official website . You can try it out in virtual machines using VMWare Workstation or Oracle VirtualBox virtualization software, although if you have an 80s-era computer and floppy disks of that type, you can run it on that physical machine.
The new release is licensed under GPL version 3, making it a free and open-source project. If you wish to compile it, you'll need a compiler from the early 90s, the well-known Borland C++ 3.1, although other compilers might also work; this is the most suitable. It's quite a hobby to get a working operating system and resurrect your old MS-DOS computer…