A super-tiny (512 bytes!) DOS with a My Little Pony schtick. Supports booting a live floppy image in QEMU.
The file archives of the Dreamland BBS, for Amiga, DOS, Linux, Windows, SunOS/Solaris, BSD, and more.
It's hard to say what all is in here, so poke around and see if anything looks good.
The Internet Archive is also aware of needing to back up this archive: https://archive.org/details/dreamlandbbs.com
An interesting operating system with file system compatibility to CP/M-80 (and other similarities).
"What I (Richard A. Leary) have done is attack the software side of the problem in order to make any 6502 system a truly workable disk based system. In addition a degree of compatibility is now possible not only between 6502 systems but with large parts of the world of CP/M systems. The result of my efforts is a system of software which I have named DOS/65."
FreeDOS is a complete, free, DOS-compatible operating system that you can use to play classic DOS games, run legacy business software, or develop embedded systems. While we provide some utilities, you should be able to run any program intended for MS-DOS. Pretty much any program that works on MS-DOS will work on FreeDOS. You can also use FreeDOS on a network! However, you may experience problems running Windows on FreeDOS. For example, Windows standard-mode works on FreeDOS, but ‘386-mode Windows for Workgroups 3.11 does not.
Github: https://github.com/FDOS
Yes, there are people who still run DOS and use WordPerfect. Here's how.
DOS on dope. The last MVC Web framework you'll ever need.
All of the controllers in DoD are batch files.
All of the views are batch files.
The model is based on batch files. The helper functions are... you guessed it! Beautiful batch files!
(Okay, I'm no purist. There's a few lines of C# for url routing and batch file execution. Everything else is either a .bat or a .cmd file. With a liberal helping of .csv mixed in.)
MicroPython/CircuitPython DOS-like shell for microcontroller boards like the RasPi Pico and Featherwing.
xBIOS is like a programmers version of DOS. With it you can easily access files from your programs without using Atari DOS. It is smaller than DOS and therefore saves memory in your programs. You can even run programs from as low as $0200, however $0800 or $2000 are more common.
Limitations
A curated list of references for development of DOS applications.
MultiMail is a Blue Wave, QWK, OMEN, OPX and SOUP offline packet reader for Unix/Linux, DOS, OS/2, Win32 and macOS.
Almost the best TrueType VGA fonts out there. Emulates DOS page 437 in Truetype. Free to download.
fdpp is a 64-bit DOS core. It is based on a FreeDOS kernel ported to modern C++. In short, FreeDOS plus-plus.
Can be compiled with clang (not gcc!) and booted under dosemu2.
Works just like DOS's sys utility to write a DOS-style MBR.
A utility that lets you edit disks and recover data, including entire partitions. Supports multiple operating systems.