(ms)dos has just a file system (it's the D in the name). It has no protected memory or scheduling, or any ability to "talk" between processes. It can load execu

(ms)dos has just a file system (it's the D in the name). It has no protected memory or scheduling, or any ability to "talk" between processes. It can load executable images .exe(MZ) or sub 64KB .com. ANd yes, it's possible to reserve memory and stay resident (TSR) I have some experience repurposing 8259 (the interrupt controller), and if you hook on the timer (8), there is nothing else to return the execution back to the 'OS'. In short I'd disagree about the real-time.