This category is for any Disk operating system.
“TRS-DOS is Tandy's first-party operating system for the TRS-80 line of computers. There are...TRS-DOS
“TR-DOS is a disk operating system for ZX Spectrum with Beta disc and Beta 128 disc interface...TR-DOS
“MSX-DOS is a Disk operating system developed by Microsoft for the 8-bit home computer standard...MSX-DOS