Xref: utzoo comp.os.os9:1433 comp.sys.m6809:1367 Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!think.com!samsung!uunet!munnari.oz.au!csc.anu.edu.au!coombs!avalon From: avalon@coombs.anu.edu.au (avalon) Newsgroups: comp.os.os9,comp.sys.m6809 Subject: Re: adding as disk drive to COCO3 Message-ID: Date: 22 Jan 91 16:04:40 GMT References: <523@ctycal.UUCP> <1991Jan21.180211.11345@mentorg.com> Lines: 22 Nntp-Posting-Host: coombs.anu.edu.au dclemans@mentorg.com (Dave Clemans @ APD x1292) writes: >From article <523@ctycal.UUCP>, by ingoldsb@ctycal.UUCP (Terry Ingoldsby): >> There is nothing you can do to fix the controller, you must slow down the >> drive. Most 1.2 MByte disk drives use motors that have two speeds. >> Sometimes there is a jumper, sometimes a wire that must be disconnected >> to select 300 RPM. Do this and you will suddenly have a working drive. >> Your storage will only be about 700K, *not* 1.2 MByte. >> >To clarify things, 1.2 Meg drives DO NOT!! spin faster than other drives. >The disk moves at EXACTLY the same speed. >The difference between them is in the electronics. 1.2 Meg drives are clocked >twice as fast as the slower drives. Controllers that can handle both drives >have the ability to switch clock rates. I have run a 1.2MB drive on my coco while using some utility program that shows disk rotation speed in RPM/ 1.2 drives go around at about 360+rpm and 720K drives at about 300 rpm (same as 360K drives). -avalon