"Nicholas Bodley" wrote:
> Yes, CP/M had directories, and iirc, they were nestable as well.

Are you sure? None of the CP/M systems I used had directories, nestable or
otherwise. Just drives (A:, B:, C:, etc.) and "user areas" (user 0-9) on
each drive. Perhaps CP/M-86 (post-dates MSDOS, and which I never had a
chance to use) had directories, but that didn't gain much traction as an
operating system as MS-DOS had by this time won the x86-based OS wars.