unknown@ucscb.ucsc.edu (The Unknown User) (04/24/91)
I am planning on designing a memory board that will take 4 megabyte SIMMs. This is a memory board for the GS that is. It will either have one or two SIMM sockets.. Depends on how much work I want to do.. heh.. I am most likely going to build one for myself no matter what.. Just for the hell of it.. To build something that I actually use day to day... (I probably shoulda kept the computer a partner and I designed in a class, but oh well... The evaluation said something like "had many RISC like properties".) If there are other people interested in this, I would build other people cards for something relatively close to cost (depends on how long it takes me to actually put another one together after I design my own).. If someone is interested in this, please E-MAIL me about it. From what Todd Whisell has told me, apparently it will only be DMA to 4 megs (plus whatever's on the motherboard), so a greater amount of DMA ability isn't a good reason to get one of these... -- /unknown@ucscb.ucsc.edu Apple IIGS Forever! WANT ULTIMA VI //e or GS?-mail me.\ \CHEAP CDs info-mail me. McIntosh Junior: The Power to Crush the Other Kids. /
bazyar@ernie (Jawaid Bazyar) (04/25/91)
In article <14942@darkstar.ucsc.edu> unknown@ucscb.ucsc.edu (The Unknown User) writes: > > I am planning on designing a memory board that will take 4 >megabyte SIMMs. This is a memory board for the GS that is. [...] > If someone is interested in this, please E-MAIL me about it. >From what Todd Whisell has told me, apparently it will only be DMA to 4 >megs (plus whatever's on the motherboard), so a greater amount of DMA ability >isn't a good reason to get one of these... Good luck. You're going to have to expend quite a bit of effort to get this working. I thought about supporting 4meg SIMMs when I designed my RAM card (built, but not yet working- noise problems). The memory slot has an MSIZE signal to choose between 256K and 1M banks. This goes back to the FPI (CYA) to tell it how to mux the addresses for the card. To support 4Meg SIMMs (and making it DMA compatible) would require latching the bank address during certain clock cycles, and combining that with a recombined address (also constructed over different clock cycles) to produce an address, which would then have to be re-muxed. In short, what you'd need would be a new DRAM controller on the board. Stick to 1M SIMMs and your life is much easier. >-- >/unknown@ucscb.ucsc.edu Apple IIGS Forever! WANT ULTIMA VI //e or GS?-mail me.\ >\CHEAP CDs info-mail me. McIntosh Junior: The Power to Crush the Other Kids. / -- Jawaid Bazyar | "Twenty seven faces- with their eyes turned to Senior/Computer Engineering | the sky. I have got a camera, and an airtight bazyar@cs.uiuc.edu | alibi.." Apple II Forever! | I need a job... Be priviliged to pay me! :-)
philip@utstat.uucp (Philip McDunnough) (04/25/91)
In article <14942@darkstar.ucsc.edu> unknown@ucscb.ucsc.edu (The Unknown User) writes:
[about a SIMM memory board project which would accept 4meg SIMM's]
You might want to check with Harris Labs first. They make the
GS Sauce which takes 1meg SIMM's( I have no idea if they will
accept more) and they also have a memory card called the Velocitas.
It's actually battery backed-up RAM hard drive which is DMA compatible
(option). It's expandable to 8megs and later to 32( they use SIMM's,
so I assume the 32megs means switching to 4meg SIMM's). The card will
go into any slot.
Seems to me that a RAM HD, 2 floppies(one of which would be a 1.44),
a GS, Mac() and Personal AppleShare for accessing more storage for the
GS would make for a rather nice system.
Philip McDunnough
University of Toronto
[my opinions...]