Re: An actual Apple Question

[Matt Jenkins <mdj@bilby.cs.rmit.edu.au>]

Tim Aaronson <taaronson@nospam.com> wrote:
> On my IIgs I note two banks of RAM on the motherboard,  a four chip set
> labeled "Standard Ram" and another four chip set labeled  "Fast Ram".
> Both are composed of 4464 chips.

The standard ram is actually slow ram; intentionally clocked at the same
speed as the //e to provide identical instruction timing in Normal speed
mode. The fast ram runs at //gs native speed. There's 128k of each,
except for the ROM03 which has a meg of it.

> What are the function of these two groupings; why the peculiar names
> 'fast' and 'standard'; how are they memory mapped vis a vis the
> expansion card?

The expansion card memory is mapped directly above fast ram, although
its access speed is somewhat slower due to parculiar address decoding.

Cheers,

Matt

Thanks for the real question! (Hope I got it right!)



-- 
              Matt(hew) Jenkins. Computer Science (RMIT Bundoora)
                           email: mdj@cs.rmit.edu.au
                            -- Site of the Month --
                            http://www.gnustep.org/