Re: CACHE????

[rubywand@aol.com (RUBYWAND)]

In article <Pine.SOL.3.91.960628084449.25061A-100000@moose>, Paul Schultz
<pschultz@med.wayne.edu> writes:

>.... I also recall posts about people piggy backing sram chips
>on top of the normal cache chips to give 128K. But, this seems a little
>bizaar and I always discounted this idea. (Apparently from what I
remember
>they claimed to physically solder the legs from one chip to the legs of
>the chip below it!).
>

     It may sound kind of bizaar; however,  the piggy-back soldering
approach for adding RAM works fine. (You do have lift at least one leg on
the piggy-backed RAM chips and run a separate wire to the circuit board.) 
NMOS and CMOS IC's are not so delicate as is commonly supposed. 


>Anyway, going above 64K is probably not doable without some significant
>design changes (significant meaning it isn't a mod that we all could do
>on our own).
>

     We would have to disassemble the Zip-GS ROM code and modify it to
handle additional banks of cache. Probably, a number of users would be
willing to handle the PROM burning for those interested in the mod.

     It would be fun to find out how much of a performance boost results
when going from 64K to, say, 256K.


Rubywand