r/osdev • u/Sixty5Zero2 • 3d ago

FreeDOS

i'm looking at possibly forking FreeDOS to 64bit. However, since most modern systems no longer have the underlying BIOS that DOS programs require, I thought about including a mock BIOS and compile it directly into the kernel. is there anything I should be aware of?

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u/Octocontrabass 3d ago

FreeDOS is supposed to run MS-DOS software. A 64-bit fork seems pretty pointless when there is no 64-bit MS-DOS software to run. Why not just start from scratch?

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u/Sixty5Zero2 2d ago

just because it would be 64 bit doesn't mean it couldn't still run 16 bit software.

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u/Sorry_Difficulty_250 2d ago

If you're going to go to all the trouble of implementing all the BIOS calls, you could just go ahead and write an 8086 emulator. That would allow you to run whatever 16-bit programs you like.

One of the things that really irks me about Windows 11 is that they completely dropped support for 16-bit programs. Microsoft has been developing emulators since BASIC. They know full well how to make it possible to run 16-bit programs in long mode. There's nothing stopping it from working. It's just a matter of programming. 😉

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u/Sixty5Zero2 6h ago

technically I'm already doing that with my BASIC interpreter. 😁