Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!elroy.jpl.nasa.gov!jato!mahendo!wlbr!pete From: pete@wlbr.imsd.contel.com (Pete Lyall) Newsgroups: comp.sys.m6809 Subject: Re: COCO upgrade Message-ID: <1991Feb5.005957.14282@wlbr.imsd.contel.com> Date: 5 Feb 91 00:59:57 GMT References: Reply-To: pete@wlbr.imsd.contel.com.UUCP (Pete Lyall) Organization: Contel FSD, Westlake Village, CA Lines: 30 In article rh2y+@andrew.cmu.edu (Russell E. Hoffman, II) writes: >Gilbert M. Sterart writes: > >>[paraphrased] .. I have a CoCo I, I wanna replace it with a CoCo III, >> what can I keep / what can I throw away... > >Well, you are pretty much in luck.. >You can re-use the disk controller and drives. If you have the VERY old style >disk controller (v1.0 ROM instead of v1.1), you may have a small problem, >but I don't think so. Not fully accurate.... the 1.0 DOS rom wasn't the only problem. The primary difference between the two ROMS was that the latter one (version 1.1) had a built in DOS command that would bootstrap track 34 into memory, and kickstart it. If you have a 1.0 ROM, a simple basic program can be used to achieve much the same thing. The larger problem is that running OS9 LII, you're running at 1.78 Mhz (similar to the old coco's high speed mode), and this causes problems with older controllers. Some folks have patched their disk driver code so that any disk access are done at the older .89 Mhz rate. Newer controllers, and most of the J&M family seem to have been unaffected by the speed changes. Pete Lyall -- Pete Lyall Contel Corporation Compuserve: 76703,4230 OS9_Net: (805) 375-1401 (24hr 300/1200/2400) Internet: pete@wlbr.imsd.contel.com UUCP: {hacgate,jplgodo,voder}!wlbr!pete