Amiga Quiz

Ethan Dicks ethan.dicks at gmail.com
Wed Nov 22 16:28:26 CST 2006


On 11/23/06, Warren Wolfe <wizard at voyager.net> wrote:
> On Tue, 2006-11-21 at 15:29 -0800, Chris M wrote:
>
> > Actually I'm at a terrible loss to name the
> > unit that used a 68020 BUT AT LEAST I GOT IT RIGHT! HA!
>
>
>    Lessee...  The 68020 was used in the Mac II, and in the Mac LC and
> at least one model of Sun workstation.  The Amiga 1200 and their game
> console used on of Motorola's economy versions of the chip, too, but not
> the regular 68020; I don't remember all the extra characters Motorola
> stuffed into the nomenclature...

The usual variants were "EC" ("embedded controller") and "LC" ("low cost").

The 68EC020 has a narrower address bus (24 bits vs 32), limiting the
amount of FAST mem to 10MB (16MB total address space), while the
68EC030 and 68EC040 are lacking in an onboard MMU (the 68LC040 is
lacking an onboard floating point processor).

You'd be unlikely to see an 'EC030 or 'EC040 in a UNIX workstation
because an MMU is just too handy for an OS that's heavily intertwined
with virtual memory.  OTOH, since AmigaOS has one address space for
all processes, it doesn't need an MMU (but can optionally take
advantage of one through programs like Enforcer).  In the realm of 68K
Macs, though, I'm not sure if they can or do use an MMU if present.

-ethan



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