westie@blake.acs.washington.edu (Eric Swansen) (09/28/89)
I'm trying to add one or two megabytes of RAM to my 6386 machine. I called the AT&T product support line, who said that only some RAM chips would work with the machine, not all. I'm not stupid, I know that 4k drams at 300 ns won't work, but what should I be looking for in the way of adding 1 meg to a 6386. A SIMM ? A SIPP? A particular manufacturer ? A certain speed ? Which form of chips.. a 1mX9, four 256kX9, what ? He also said that some machines can't use the 1m chips, for some reason. How can I tell if my can or can't ? These questions I ask of you in desperation.... Eric C. Swansen University of Washington Graduate School of Public Affairs (Administration) DC-13 westie@blake.acs.washington.edu PS- Any good sources for cheap chips ?
bobd@hpuxa.ircc.ohio-state.edu (Bob DeBula) (09/30/89)
To answer your questions as best I can (I have a 6386 and did upgrade the memory some time ago). You want SIMMs. You want 120ns or faster (100ns or 80ns) SIMMs. You want low profile SIMMs or you can kiss the use of one of the 6386s too few expansion card slots goodbye. You *must* have either all 256K or all 1Mb SIMMs on a memory board (mixing them is a *big* NONO). If you decide to go to 4Mb and no further, then you can get 256K SIMMs and load the board full. If you wish to someday go beyond 4Mb, then you need to look at selling your 256K SIMMs and replacing them with 1Mb SIMMs. You must upgrade in 4 SIMM increments (due to the 32 bit memory access). The SIMMs must have the parity chip (i.e. they must be 256Kx9 or 1Mbx9). Figuring out the DIP switch settings is the stuff of which data processing legends are made. It is not simple & has no easily grasped underlying logic that an ordinary mortal would understand as far as I know. AT&T includes a smallish pamphlet with *their* memory upgrade explaining how to set the DIPs. I won't go into my opinion of vendors who don't include 25 cent pamplets with $3,000+ machines at this time (I've flamed 'em before on here for this one). When I posted the same request there were many folks (resellers mainly) who offered to send me one of the many of these they had from installing AT&T upgrades for systems configured with AT&T upgrades. Todays project (for which someone would gain AT&T 6386 users undying gratitude) would be for someone to write a program which eliminates the need for the book (i.e. you tell it what you want to upgrade to & it tells you which SIMM sockets and which DIP switches). For someone who understands the rational of the methodolgy used for the settingsthis should be a piece of cake (not me: I haven't spent enough time looking at it to understand it and I doubt it would be a requirement in VCR instruction sheets (although you never know, VCR vendors also masters of confusion and are always on the lookout for archane ways to confuse the poor purchaser who just wants to tape Dr. WHO on Saturday nights) :-). -=- ========================================================================== Bob DeBula | Internet: bobd@hpuxa.ircc.ohio-state.edu The Ohio State University | Disclaimer: These are my views, not the U's