Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!sun-barr!newstop!exodus!stpeter.Eng.Sun.COM!cmcmanis From: cmcmanis@stpeter.Eng.Sun.COM (Chuck McManis) Newsgroups: comp.sys.amiga.misc Subject: Re: Adding an IBM type 3.5" High Density Drive to Amiga Message-ID: <13613@exodus.Eng.Sun.COM> Date: 20 May 91 04:44:38 GMT References: <1991May7.002625.1696@tplrd.tpl.oz.au> Sender: news@exodus.Eng.Sun.COM Organization: Sun Microsystems, Mt. View, Ca. Lines: 24 In article <1991May7.002625.1696@tplrd.tpl.oz.au> (Mark Bower) writes: >Unresolved Issues: >~~~~~~~~~~~~~~~~~~ > * Has anyone had any success in using the High Density capability > of these type of drives ? I'll try to write a driver when I > get time but i'd rather not re-invent the wheel if someone > else has done it. Nontechnical people shouldn't try things they don't understand. 1.44MB drives are that way because they use a 500KHz clocking frequency, the Amiga can only generate a 250Khz bit rate clock. Sorry you lose. Read up on disk electronics (good references are early issues of BYTE or Kilobaud Computing which talk about 8" floppies that also use 500khz bit clocks). Also note that the recording bias of the read/write head is different than it is for regular floppies (about 600 oresteads as opposed to 450 oresteads) any good text on magnetic recording will explain it to you. --Chuck -- --Chuck McManis Sun Microsystems uucp: {anywhere}!sun!cmcmanis BIX: Internet: cmcmanis@Eng.Sun.COM These opinions are my own and no one elses, but you knew that didn't you. "I tell you this parrot is bleeding deceased!"