Minimal OS (was Trouble with int 13h extended commands)

[cnlohr]

Are there any good articles about how one would have a minimal OS under newer systems? I.e. purpose-build things that are less than 32kB? I mean I don't need it now, but I periodically write my own stuff like that. The only reason this was an issue this time was that my kernel was slightly too large to fit in the first cylinder on a 720 floppy.

[Combuster]

a minimal OS (...) less than 32kB

Mind you that an OS is more than just the kernel. You could probably make yourself something like a DOS shell in that space if you know how to write simple effective code, but you can hardly get the chance to write more than the simplest drivers.

Typically, when you talk about these sizes, you're actually having an embedded application in mind, rather than an operating system.

32kB (...) too large to fit in the first cylinder on a 720 floppy

No sweat. Even a 1.4M floppy needs four tracks to store 32k/64 sectors.