Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!ub!uhura.cc.rochester.edu!rochester!pt.cs.cmu.edu!o.gp.cs.cmu.edu!andrew.cmu.edu!es2a+ From: es2a+@andrew.cmu.edu (Eric Stuyvesant) Newsgroups: comp.sys.atari.st.tech Subject: Re: Memory upgrade with 256Mbit rams. Message-ID: Date: 16 Mar 91 02:42:08 GMT References: <1991Mar15.161629.20972@lth.se> Organization: Class of '91, Carnegie Mellon, Pittsburgh, PA Lines: 22 In-Reply-To: <1991Mar15.161629.20972@lth.se> First, if you have access to 256 Mbit parts cheap, I'd like to pick up a few! I'll assume you mean 256 Kbit. The ST's MMU expects to see one or two banks of RAM, where each bank is 16 bits wide. So, you need to have 16 chips to fill a bank. The 520 has one bank of 256 Kbit chips, the 1040 has 2 banks of 256 Kbit chips. The Mega 2 has one bank of 1 Mbit chips, and the Mega 4 has two banks of 1 Mbit chips. The final answer is that, since you have a 1040, your machine already has both banks full of 256 Kbit chips, so you can't easily upgrade with 256 Kbit parts. You must use 1 Mbit parts to replace one or both banks, getting 2.5 Megs or 4 Megs respectively. While it is theoretically possible to do what you are attempting, it likely would wind up being more hassle than it's worth (even if you got the chips for free). Buy 1 Mbit parts to upgrade your existing machine, or better yet, an STE, and upgrade with SIMMs. Sorry, this probably isn't the answer you wanted to hear. -Eric Stuyvesant es2a+@andrew.cmu.edu || es2a%andrew@CMCCVB || JNET%"es2a%andrew@CMCCVB" al782@cleveland.Freenet.Edu Wanna buy brand new Lynx games: Blue Lghtng, Slime World, Zendocon for $22ea? Go MEMS!