Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rutgers!netnews.upenn.edu!eniac.seas.upenn.edu!hodas From: hodas@eniac.seas.upenn.edu (Josh Hodas) Newsgroups: comp.sys.mac Subject: Re: New SIMMs for the Macintosh IIci??? Message-ID: <14730@netnews.upenn.edu> Date: 26 Sep 89 03:27:32 GMT References: <1150@orbit.UUCP> Sender: news@netnews.upenn.edu Reply-To: hodas@eniac.seas.upenn.edu.UUCP (Josh Hodas) Organization: University of Pennsylvania Lines: 44 In article <1150@orbit.UUCP> granteri@pnet51.orb.mn.org (Grant Erickson) writes >jeff@ndcheg.cheg.nd.edu (Jeffrey C. Kantor) writes: >>In art <1149@orbit.UUCP>, granteri@pnet51.orb.mn.org (Grant Erickson) writes: >>> ... 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? >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. > >Grant Erickson Well, I called Chip Merchant this afternoon and the woman on the phone claimed that their Samsung 80ns SIMMS are FPM. I do not know how one could confirm this though. If I post a chip # from the simm, does someone have a Samsung part list to look it up on. Speed was always an easy thing to identify from the -xx number, but I have no idea what identifies an FPM chip. Josh ------------------------- Josh Hodas (hodas@eniac.seas.upenn.edu) 4223 Pine Street Philadelphia, PA 19104 (215) 222-7112 (home) (215) 898-5423 (school office)