I first got to know MS-DOS 6.22/Win 3.1 on an old AST 486DX2/66 (AST Adventure 6066d). I do also remember the editing of config.sys and autoexec.bat files to get my MS-DOS games to have enough conventional memory. I messed with CP/M with the Commodore computers (Commodore 64 and Commodore 128D), but got really no where with it.