>Date: Thu, 10 Oct 2002 12:19:53 -0600 >From: Philip Stortz <[EMAIL PROTECTED]>
>the floppy interface sounds very challenging. i think the 800k >floppies still used variable speed, >which means it's probably also something tricky with the particular >pc drive involved. Well, there's that Xicor 9103 on the board. The 9103 is a linear digital potentiometer. I'm kind of expecting to find that it's hooked up to control the speed of the floppy somehow and that it's taking it's input from that GAL16V8. I haven't gotten that far yet, but that's my off the cuff guess. >many of the >"copy protect" schemes on the apple II did things like that, and >made floppies useless on other >brands of drives for the apple II when they came out (not to mention >people quickly figured it out >anyway). it wouldn't surprise me if there had been a slight mod >done on the floppy as well >possibly, that would seem to be the easiest way to get the variable >speed, i.e. to hack into the >speed controller on the drive. I had not thought of that. Thank you. I will closely examine the floppy drive mechanism for modifications on its board. >or it may let the drive run at constant speed, but change the bit >rate fed to the drive which seems likely given the complexity you >describe, although that has other >likely problems with the drive hardware since i think they usually >do that data/clock recovery stuff. The WD9232 is a Digital Phase Lock Loop Disk Data Separator. I'm not entirely sure what that means but I hope to find out. I think it has to do with the data/clock recovery that you mention above. I managed to track down the data sheet for the thing. The odd thing is that the data sheet for the 37C65 claims that an external data separator is not needed, yet there's that 92C32. There are more recent floppy controllers that shouldn't need the 92C32 at all and the 92C32 is one of those chips I'm getting $9 price quotes on, but I'd really have to dig into how this thing works to get rid of the 92C32. And it's possible that access to the lines between the data separator and the controller is needed to make the 800K magic work. >in any case, good luck, even if you did misspell my name (i'm not >one of those people who cares >allot, besides which it's always being misspelled, and as most know, >i can't spell anyway, spell >check on emails is somewhat embarrassing most of the time for me.) My apologies, Philip. You know, I thought about going and double checking the spelling at the time, but it was a long post and I just wanted to finish typing it. I notice that I also wrote 'are' one place where I meant 'and' but I consistently misspelled your name twice and I'm sorry. Jeff Walther -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
