4 ms·
Motorola sold an MMU that was paired with the 68020 - the 68851, but the likes of Sun kept using their own (which were simple to implement, a few fast SRAMs and
by pinewurst 3y ago
Motorola sold an MMU that was paired with the 68020 - the 68851, but the likes of Sun kept using their own (which were simple to implement, a few fast SRAMs and a little TTL). The 68010 was the earliest family member that supported clean instruction restart on a page fault and had its own, infrequently used MMU - the 68451. Again most system vendors preferred to do their own. If you wanted "real" virtual memory on a 68000, you had to do kludges like running 2 68ks in parallel, switching on every page fault.
- ghaff 3y agoMotorola seemed to like their separate MMU chips. I don't remember the exact models but some of their (largely unsuccessful RISC) 88K processors had one too.
- pinewurst 3y agoYou didn't have an option with at least the initial 88k. They couldn't fit it all into one chip so you had to buy one 88100 and at least one 88200. The next gen 88110 was single chip.
- kjs3 3y agoYou didn't have to have an 88200, particularly for embedded apps. The 88k based NCD X terminals don't have an 88200 for example.