🚀 go-pugleaf

jeff@ndcheg.cheg.nd.edu (Jeffrey C. Kantor) writes:
>In article <1149@orbit.UUCP>, granteri@pnet51.orb.mn.org (Grant Erickson) writes:
>> After a long run down of the Macintosh IIci and the Macintosh Portable and the
>> Minnesota Macintosh Users Group meeting, I was enlightend to the fact that in
>> the IIci you must use 80 nanosecond F)ull P)age M)ode SIMMs. These must be
>> used to take advantage of the burst-mode of the 68030. 
>> 
>>  [stuff deleted]
>
>What is a F)ull P)age M)ode SIMM?  I know what the 80ns bit is all about,
>but what does the FPM bit mean?
>
>More to the point, if I order 80ns SIMMs from the usual list of SIMM vendors,
>will they work in a MacIIci?
>
>
>-- 
>Jeff Kantor
>                                       US Mail:  Dept. of Chemical Engineering
>internet: jeff@ndcheg.cheg.nd.edu                University of Notre Dame
>    uucp: iuvax!ndmath!ndcheg!jeff               Notre Dame, IN   46556  USA

Well as Paul Pashibin of Apple Corporate in Bloomington, MN explained it as
being this. Lets say you have a data word. The 68030 grabs the first 1/4 in 5
cycles, the 2nd 1/4 in 5 cycles, the 3rd 1/4 in 5 cycles, and the final 1/4 in
5 cycles. This ends up taking 20 cycles consequently. So with the FPM SIMMs
together with the 68030's burst mode, it reads 1st: 5 Cycles and the next
consecutive 3 in 2 Cycles each. There for you have a total of 11 Cycles
compared to 20 giving you a 181% speed increase in that situation. I myslef do
not know if people like Chip Merchant will have these at the current low $89
price for NORMAL 80Ns SIMMs.

Disclaimer: I have no affiliation with Apple nor Chip Merchant or anyother
company that you might want to dream up.

Grant Erickson

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