Path: utzoo!utgpu!watmath!isishq!f171.n221.z1.FIDONET.ORG!izot From: izot@f171.n221.z1.FIDONET.ORG (Geoffrey Welsh) Newsgroups: comp.sys.cbm Subject: Re: 1764 and C-128 Message-ID: <1346.23DEB73D@isishq.FIDONET.ORG> Date: 23 Jan 89 23:23:05 GMT Sender: ufgate@isishq.FIDONET.ORG (newsout1.25) Organization: FidoNet node 1:221/171 - Izot's Swamp, Kitchener ON Lines: 44 > From: jgreco@csd4.milw.wisc.edu (Joe Greco) > Message-ID: <513@csd4.milw.wisc.edu> > > I've heard of people using the 1764 on the 128, but with somewhat > limited success since a fair amount of software is expecting a 1750 > (very little seems to expect a 1700). The problem lies, not with what the software expects, but with what the REU controller reads. There is only one bit to indicate the size of RAM, and most 128 programs test it rather than do a RAM limit test. The 1700 (128K) had the bit cleared, the 1750 (512K) had it set. The 1764 (256K) has it set. I know the folks at CBM are 'listening', so I won't give a detailed opinion on the intelligence of that design decision. > I've also heard conflicting stories about the configuration of the > 1764's RAM. I know that the 1700 is two banks of 64K, and the 1750 is > two banks of 256K. I heard originally that the 1764 was two banks of > 128K (!!) (rather odd) but have heard since that it is just one bank > of 256K. I know that there could be two versions of the expander out > there, has anyone seen either of these two configurations? In terms of hardware, the 1764 uses one bank of 256K DRAMs (some have soldered another 8 RAM chips to bring the cartridge to 512K) but, from a software point of view, ALL the RAM expanders have 64K banks (allowing 16-bit addressing within the bank). =========================================================================== Internet: Geoffrey.Welsh@f171.n221.z1.fidonet.org | 66 Mooregate Crescent Usenet: watmath!isishq!izot | Suite 602 FidoNet: Geoffrey Welsh on 1:221/171 | Kitchener, Ontario PunterNet: 7/Geoffrey Welsh | N2M 5E6 CANADA BBS: (519) 742-8939 24h 7d 300/1200/2400bps | (519) 741-9553 =========================================================================== | "I don't need a disclaimer. No one pays any attention to what I say." | =========================================================================== -- Geoffrey Welsh - via FidoNet node 1:221/162 UUCP: ...!watmath!isishq!171!izot Internet: izot@f171.n221.z1.FIDONET.ORG