John Hardy on Nostr: An MSDOS .COM file was much the same except that it was 64K in total for all code, ...

An MSDOS .COM file was much the same except that it was 64K in total for all code, data and stack but that could be located anywhere because of the segmented memory model. A common trick was to load multiple .COM files into memory at one and wire them up to timers and interrupts to create a simple multi-tasking system (TSR terminate and stay resident utilities)