Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!think.com!yale!cmcl2!uupsi!sunic!ugle.unit.no!ugle.runit.sintef.no!thoger From: thoger@solan.unit.no (Terje Th|gersen) Newsgroups: comp.sys.ibm.pc.misc Subject: Re: Original AT Memory Message-ID: Date: 6 Mar 91 02:38:13 GMT References: <1991Feb27.201755.22029@sbcs.sunysb.edu> <5422@media-lab.MEDIA.MIT.EDU> Sender: news@ugle.unit.no Organization: Institute of Physical Chemistry, NTH Lines: 51 In-Reply-To: henry@garp.mit.edu's message of 5 Mar 91 00:06:00 GMT In article <5422@media-lab.MEDIA.MIT.EDU> henry@garp.mit.edu (Henry Mensch) writes: dhoelzer@csserv2.ic.sunysb.edu (David S Hoelzer) writes: |> I'm looking for someone with information about the original 6 MHz AT |> Memory. Now on the XT's, there was a way to upgrade the board to 640.. I'm |> looking for someone with info on the same thing for the 512k AT motherboard. |> This is the full-sized baby... me too! i need a 128k memory expansion for a PC/AT, and these seem to be (rightfully) a scarce item these days ... while my original AT has 1Mb in it, only 512k is visible to DOS (the other 512k is extended memory, used as a ram diskette :>). any clues would be welcome. BocaRAM sells a card called the TophAT, which is a drop-in 128K memory expansion for 512K AT's. I don't remember the price exactly, but it wasn't too bad.. If memory serves me right, the original AT used some 128 kilobit piggy-backed memorychips that might be hard to come by today. (I think it was something like two 64 kilobit chips soldered together. Anybody out there have some sure knowledge on this ??) On the other hand, an EMS 4.0 card can usually be set up to backfill memory up tp 640K, giving you the effect you want and EMS memory as a bonus. These cards run about USD 100-120 unpopulated. Beware, though if you intend to keep these cards when upgrading to a 386, that some of them fail at higher processor- or bus-speeds. Two cards known to flunk this test are the BocaRAM AT (not the Plus), and an AST Premium Advantage. Also, some of the older boards do not do EMS 4.0 in hardware, but only emulate it with software. These boards cannot be used for multitasking under DesqView/Windows-286. (The BocaRAM AT fails this test, too.) -Terje -- ____________________________________________________________________________ thoger@solan.unit.no | Institute of Physical Chemistry THOGER AT NORUNIT.BITNET | Div. of Computer Assisted Instrumental Analysis | Norwegian Institute of Technology