Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!wuarchive!zaphod.mps.ohio-state.edu!rpi!peck From: peck@ral.rpi.edu (Joseph Peck) Newsgroups: comp.sys.amiga.hardware Subject: Re: What Happens If You Have > 9 Meg?? Message-ID: <-G3^5R#@rpi.edu> Date: 16 Jan 91 16:13:50 GMT References: <6931@crash.cts.com> <744@cbmger.UUCP> <677@caslon.cs.arizona.edu> Organization: Rensselaer Polytechnic Institute, Troy NY Lines: 87 Nntp-Posting-Host: ral.rpi.edu In article <677@caslon.cs.arizona.edu> dave@cs.arizona.edu (Dave P. Schaumann) writes: >In article <744@cbmger.UUCP>, peterk@cbmger.UUCP (Peter Kittel GERMANY) writes: >|In article <6931@crash.cts.com|lgreen@pnet01.cts.com (Lawrence Greenwald) writes: >||I've always been curious about the 9 Meg limit on the 2000. What would happen >||if I were to have more than 9 meg in the machine, say in one of the following >||combinations: >|| >||1) 1meg motherboard memory >|| 2meg A2052 card >|| 8meg GVP Series II w/RAM >|| --- >|| 11 meg physical RAM >|| >||2) 1meg motherboard memory >|| 8meg GVP Series II w/RAM >|| 4meg 32-bit memort (A2630) >|| --- >|| 13 meg physical RAM >|| >||What would happen? Machine refuse to boot? Software go crazy? >| >|[ extra memory would not be recognised ] > >How about writing some kind of device driver that would recognise the >additional RAM and use it as another RAM: disk? Sort of like the memory >expansion boxes that are around for the C64/128 line (sorry, I forgot the >part #). The biggest problem that you face is the lack of address lines for that much ram. There are a couple of solutions to the problem: 1) Add a little extra hardware/software and set up your memory in banks. The problem here is that EVERY program that you run must be aware of the bank switching, and, ummm, this is a dumb idea on the amiga (except for maybe chip ram, but still.... ). 2) Purchase an '020 or '030 (or soon to be '040) accelerator that supports 32 bit memory outside of the 68000 memory space. I believe that all of them do. 3) Build the Lucas/Frances accelerator, which allows at least another 4meg of 32 bit memory, and it is probably pretty easy to add more. 4) Finally, if you are looking for the least expensive way to add more memory, and you want to avoid as many of the clock speed/processor incompatabilities as possible, build the "Joe Peck's Incredibly Nifty 68012 Memory Board Expansion Project!" (I am probably going to regret mentioning this :) A little known processor in the Motorola 68000 family is the 68012. It is identical to the 68010, with the exception of having additional address pins for a 2 gigabyte space. A little circuit board with some additional decoding circuitry would be needed, as well as your own memory board. Done correctly, the processor daughter board would sit in the processor socket on the motherboard, and the memory board would sit in a Zorro II slot. A small ribbon cable would carry the additional address lines and decoding circuitry between the two. *BEFORE* I get 18 gazillion requests for this hack, all I have is some of the logic worked out in my *head*. The two main obstacles in my path are these: I don't know if the 68012 is even available any more. I have never designed or even looked at a memory board for the Amiga in my entire life. Oh yeah, one more. I plan on getting a 3000 (or a 3500 :), and that would satisfy my memory requirements. However, if anyone is vaguely interested in what I am thinking, at some point in time I can post or email another paragraph or two.... Right now I am finishing a commercial game (which all of you should run out and purchase. Maybe even several since it will be so good. It doesn't even break any programming rules (yet :). ) > >Of course, this is a purely academic interest on my part, as I am still working >to get across the A500/1Meg barrier. :( > > >|Best regards, Dr. Peter Kittel // E-Mail to \\ Only my personal opinions... >|Commodore Frankfurt, Germany \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk > >Dave Schaumann | And then -- what then? Then, future... >dave@cs.arizona.edu | -Weather Report Joe Peck peck@ral.rpi.edu P.S. I have also designed a 14Mhz hack that I believe takes care of the E-clock problem. No schematics yet, just a logic diagram and a brief description..... At some point I will get around to posting it....