Strictly-speaking modern x86 computers running Windows should be compatible with any software written for the very first MS-DOS PCs starting with the original IBM PC and its clones. In practice, it's ...

Microsoft’s MS-DOS (and its IBM-branded counterpart, PC DOS) eventually became software juggernauts, powering the vast majority of PCs throughout the ’80s and serving as the underpinnings of Windows ...

I cut my teeth on DOS with DOS 6, so admittedly I was only around for the more matured version of the OS, but it still taught me an awful lot of about computers that has served me very well since then ...