Re: 18 Mhz IIgs?

[Rubywand <rubywand@swbell.net>]

"Michael J. Mahon" writes ...
> 
 ....
> 
> I thought that all IIgs accelerators depended on PALs, which have
> speed limits, and cannot be replaced by faster chips because their
> logic is not documented.
> 
> I would expect that after everything else is speed-upgraded, these
> chips would remain as the fundamental limiter.  And I'm sure that
> there are faster ones and slower ones--they only had to pass the
> original acceptance test.
> 
 ....

     That would go a long way toward explaining variations in upgradability
among same-model boards.

     Another problem is that gate delays are figured to work with the original
design. Even if all of the chips can handle the higher speed, you run into
situations where data or some signal doesn't get to where it needs to in the
time allowed.



Rubywand