Path: utzoo!attcan!uunet!bu.edu!rpi!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: Reading 1581 disks
Message-ID: <14684@cbmvax.commodore.com>
Date: 27 Sep 90 14:18:54 GMT
References: <2041@lpami.wimsey.bc.ca>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 26

In article <2041@lpami.wimsey.bc.ca> lphillips@lpami.wimsey.bc.ca (Larry Phillips) writes:
>In <439@cbmger.UUCP>, peterk@cbmger.UUCP (Peter Kittel GERMANY) writes:

>>With all the track-to-track read speed changes in the 1541 format? How do 
>>they manage that? Is the data density on a 1541 so small compared to an 
>>Amiga or PC that these variations can be easily followed by the decoding 
>>software? Sounds very interesting.

>If memory serves, there were no track to track red speed changes... only a
>smaller number of sectors per track as you approached the center of the disk.

That's exactly right.  The 1541/71 drives did write tracks at varying angular
densities, to allow more sectors per track to live in the outer tracks.  But
it was all done electronically, by changing the actual angular read/write
density, rather than by changing drive speeds.  The only system I know of that
achieved this trick via variable motor speeds was the Mac.  And even new Macs
now do it electronically.

>It is not possible to both understand and appreciate Intel CPUs.
>    -D.Wolfskill
>|   //   Larry Phillips                                                 |

-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
	Standing on the shoulders of giants leaves me cold	-REM