Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!vax5.cit.cornell.edu!q4kx From: q4kx@vax5.cit.cornell.edu (Joel Sumner) Newsgroups: comp.sys.apple2 Subject: Re: Apple IIGS's Memory Limit Message-ID: <1991Jun22.105416.5651@vax5.cit.cornell.edu> Date: 22 Jun 91 10:54:16 EDT References: <9106191921.AA23636@apple.com> <43521@cup.portal.com> <32395@dime.cs.umass.edu> Distribution: comp Organization: CIT, Cornell University Lines: 39 In article <32395@dime.cs.umass.edu>, gray@ibis.cs.umass.edu (Lyle Gray) writes: > In article <43521@cup.portal.com> -Rich-@cup.portal.com (Richard Sherman > Payne) writes: >>>On Tue, 18 Jun 1991 20:20:04 GMT Lyle Gray said: >>>>>The on-board RAM lies within the 8MB space. >>>> >>>>I seem to recall (from the original owner's manuals) that the RAM limit was >>>>8.25 Mb, not 8 Mb. The remaining addressable space (up to 16 Mb) was >>>>reserved >>>>for ROM expansions. [incorrect assumption Rich Payne didn't know how to multiply deleted] > All right, now you've annoyed me. ;-) _I_ did not make that mistake (I'm > quite familiar with it, from having to educate people about the real meaning > of 1 megabyte). I was merely stating what I recall reading in the original > owner's manuals for the IIgs. I can't find my manuals right now (dig, dig), > but that _is_ what I remember: slightly more than 8 megs for RAM, slightly > _less_ that 8 megs for ROM. It's possible that has changed since, but that's > what I remember. > You are correct. According to the GS/OS reference manual (page 32), the memory map is as follows [edited for briefness]. RAM - Banks $00-$7F (8Megs) + Banks $E0-E1 (128K Shadow Ram) Expansion ROM - Banks $F0-$FD Total ROM Space - Banks $F0-$FD + Banks $FE-$FF (Onboard ROM) If shadowing is on, of course, you only effectively have 8Megs of storage because Banks $E0-$E1 mirror banks $00-$01. -- Joel Sumner GENIE:JOEL.SUMNER This .sig may not be used q4kx@cornella.ccs.cornell.edu q4kx@cornella for public viewing or q4kx@vax5.cit.cornell.edu q4kx@crnlvax5 rebroadcast without the .................................................... express written consent The impedance of absolutely nothing is 377 ohms. of major league baseball.