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From: mjp@spice.cs.cmu.edu (Michael Portuesi)
Newsgroups: comp.sys.amiga
Subject: controlling the Amiga drive
Message-ID: <1109@spice.cs.cmu.edu>
Date: Wed, 17-Dec-86 17:37:50 EST
Article-I.D.: spice.1109
Posted: Wed Dec 17 17:37:50 1986
Date-Received: Thu, 18-Dec-86 05:43:24 EST
Reply-To: mjp@spice.cs.cmu.edu (Michael Portuesi)
Organization: Carnegie-Mellon University, CS/RI
Lines: 41

Keywords:


Does anybody know whether the Amiga disk controller can be made to
read (and write) other formats besides Amiga's?  In particular, the
thought of writing a utility to copy files from Amiga to Mac disks and
vice-versa interests me.

Please keep in mind that the Mac disk drives are variable-speed.
Therefore, one would have to be able to control the speed on the Amiga
drive to write things a Mac would understand.  The Hardware Manual
seems very vague on this topic.  I do know that if I connect a 5 1/4"
drive to my machine I can read Apple II disks (big deal).

I know it's impossible to do things from the Mac end because the
MacPlus disk drive controls the speed of the disk itself...the system
software cannot control it (unlike the orginal Mac and Mac 512K
machines).  Not that I wanted to write the software for the Mac
anyway, but the variable speed certainly poses a problem in accessing
data from the Amiga end.

Another problem is that Apple itself is reluctant to divulge the
details on how its drive works in the first place.  The documentation
for their file system refers to everything in "logical blocks" and
doesn't say where things are physically located on a 3 1/2" disk
(which makes sense, since the filesystem should work the same
regardless of media and it shouldn't make any difference to an
application programmer anyway)

I just want to know if this is technically feasible before I start
sticking my nose in a bunch of Mac documentation.

-- 

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| Mike Portuesi								     |
| Carnegie-Mellon University Computer Science Department		     |
|									     |
| ARPA: mjp@spice.cs.cmu.edu						     |
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| "Talking about music is like dancing about architecture"		     |
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