>Sim020 simulates most instructions from 68020's instruction set because >the 68000 >is designed so it can emulate a bigger instruction set than its native >one. But it >can't simulate the PMMU of the 68020, with its addressing and virtual memory >capabilities. So if I'm not very wrong, it's impossible to RAM Doubler to >run on >anything less than a 68020... >Antonio Rodr�guez (Grijan)
Uhhhhhh, actually, the 68020 doesn't have a PMMU either. The Mac II came with a separate chip called an AMU. Then they made available an upgrade that included a PMMU chip that plugged into the AMU socket. So when you see, on one of my web pages for instance, a reference to "68020 with PMMU", that's 2 chips. I don't know if the LC could be upgraded with a PMMU, or whether it already had one. The 68030 was the first to include onboard PMMU. Gamba <http://home.earthlink.net/~gamba2> -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
