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Path: utzoo!watmath!clyde!rutgers!cbmvax!grr
From: grr@cbmvax.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: MFM format and possible improvments
Message-ID: <1345@cbmvax.cbmvax.cbm.UUCP>
Date: Thu, 5-Feb-87 04:25:55 EST
Article-I.D.: cbmvax.1345
Posted: Thu Feb  5 04:25:55 1987
Date-Received: Sat, 7-Feb-87 11:47:58 EST
References: <8702050359.AA01021@cory.Berkeley.EDU>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 20

In article <8702050359.AA01021@cory.Berkeley.EDU> dillon@CORY.BERKELEY.EDU (Matt Dillon) writes:
>
>	Unfortunetly, I'm no expert on disk media and hardware.  This is my
>understanding:

Suggest you do a little more research on MFM, GCR and RLL implementation.
The Amiga floppy controller function lets you spit out whatever flux
transitions you want at a fixed clock rate.  There is also provision for
write-precompensation (bit shifting) for either MFM or GCR standards.

The Amiga at one point was to have GCR formatted floppies, but somewhere along
the line it was decided to switch back MFM.

Feel free to experiment.  Note that GCR and RLL codes may require different
time-domain filter parameters in the analog drive electronics.  Typically,
wider bandwidth is needed to prevent droop on missing transitions...
-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)