Re: companion product for GSBarnDoor

["Michael J. Mahon" <mjmahon@aol.com>]

mdj wrote:
> On May 19, 4:23 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
>
> > I'm not sure how the IIgs fast memory operates, except that accesses
> > run at 1MHz when they occur to addresses "shadowed" in the "slow"
> > RAM space of the traditional Apple II.
>
>
> I was under the impression a more 'usual' approach was used with the
> DRAM controller stealing some cycles for refresh purposes.
>
> ISTR this makes the effective bandwidth of fast memory closer to
> 2.5Mhz than 2.8, which due to the nature of the 65xx series
> effectively means the IIgs's processing speed is effectively 2.5Mhz
> (ish)

I'm glad to hear that the design is more efficient.

As you know, my IIgs familiarity is very spotty (like my interest
in the IIgs).  ;-)

-michael

NadaNet and AppleCrate II: parallel computing for Apple II computers!
Home page: http://home.comcast.net/~mjmahon

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