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From: scotty@l5comp.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Reading MacDisks on Amiga
Message-ID: <124@l5comp.UUCP>
Date: Thu, 14-May-87 09:27:13 EDT
Article-I.D.: l5comp.124
Posted: Thu May 14 09:27:13 1987
Date-Received: Sat, 16-May-87 14:41:32 EDT
References: <8705080543.AA18112@cory.Berkeley.EDU> <112@l5comp.UUCP> <3038@well.UUCP>
Reply-To: scotty@l5comp.UUCP (Scott Turner)
Organization: L5 Computing, Edmonds, WA
Lines: 41

In article <3038@well.UUCP> ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) writes:
>	Without getting coarse, Scott, I (and many others) would greatly
>appreciate it if you would explicitly quote the manual and not simply ask us
>to take your word for it.
While I have you on the horn here Leo, I (and many others) would greatly
appreciate it if you would take that bike and smash it down a bit and not force
everyone to pay $$$ for useless data. As for manual quotes I'll keep that in
mind the next time I offer help. I don't imagine everyone here has the luxury of
their own set of manuals. [one public tit for your public tat, 'nuff said?]

>	I have inspected my hardware manual, and the only thing I can find
>that might possibly be related to varying bit densities on the disk is the
>ADKCON register, bit 8 (FAST).  This bit switches from 2 to 4 microseconds
>per bit cell.  Was this what you were talking about?
If it quacks like a duck... Yes Leo, although I think a term stronger than
'possibly' could be used for something that SAYS it changes the bit timing.

>	I presume you mean it turns on (300 rpm) and off (0 rpm).  I see no
>other software controls to vary speed in the manual.  Am I blind (I
>personally don't think so)?
What I meant is that the drive in the Amiga does not turn on or off in 0us.
By applying a properly timed sequence of motor on/off commands to the drive we
can control it's speed to a degree. I have no data on what kind of range can be
achieved with the Amiga's 3.5" drive but this idea has been used on the PC to
change the drive speed for less useful things like copy protection.

To head off any more semi-hostile responses, I'm attempting to do more with my
messages than just state facts, that most of us already have, over again. I'm
attempting to elicit discussion by provoking thought and response. Sometimes
things go in directions other than expected, like Leo's statement about manual
quotes, but that's the whole point. Discussions more often than not lead to
everyone learning something. Of course everyone is free to emasculate me for
attempting this, or we can discuss it. But this form of dealing with questions
has worked well on other forums (like GEnie).

Scott Turner

-- 
L5 Computing, the home of Merlin, Arthur, Excalibur and the CRAM.
GEnie: JST | UUCP: stride!l5comp!scotty | 12311 Maplewood Ave; Edmonds WA 98020
If Motorola had wanted us to use BPTR's they'd have built in shifts on A regs
[ BCPL? Just say *NO*! ] (I don't smoke, send flames to /dev/null)