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From: roy@gatech.UUCP (Roy J. Mongiovi)
Newsgroups: net.micro.pc
Subject: Reading Diskettes on the Victor 9000
Message-ID: <2815@gatech.UUCP>
Date: Mon, 12-Dec-83 15:04:06 EST
Article-I.D.: gatech.2815
Posted: Mon Dec 12 15:04:06 1983
Date-Received: Wed, 14-Dec-83 01:14:28 EST
Organization: School of ICS, Georgia Institute of Technology (Atlanta, GA)
Lines: 22

I believe that the Victor 9000 achieves its tremendous (1.2 MB
versus 360 KB on the IBM PC) increase in density due to several
factors:

	1) The diskettes are written at 96 TPI rather than 48.
	2) The diskette rotational speed is varied to allow the
	   outer tracks to be as dense as the inner tracks.
	3) Group encoding is used to store data on the diskette,
	   thus eliminating sync pulses.

Now you can get around the 96/48 TPI problem (for reading, not
writing) by simply reading every other track, and I believe that
there is a drive speed per track vector that can be reprogrammed
to keep the rotational speed constant.  But I don't see any way
that you can read diskettes that were not written using group
encoding since that is a function of the analog part of the disk
drive.
-- 
"Roy J. Mongiovi"
  USA:  School of ICS, Georgia Institute of Technology.  Atlanta, GA 30332
 uucp:  ...!{sb1,allegra,ut-ngp}!gatech!roy  ...!duke!mcnc!msdc!gatech!roy
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