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From: hase@netmbx.UUCP (Hartmut Semken)
Newsgroups: comp.sys.atari.st
Subject: Re: 2ms and no verify
Message-ID: <2084@netmbx.UUCP>
Date: 13 Mar 91 12:39:14 GMT
References: <1991Mar07.080136.28020@ecst.csuchico.edu> <2887@krafla.rhi.hi.is>
Organization: netmbx, Berlin, West Germany
Lines: 35

adamd@rhi.hi.is (Adam David) writes:

>In <1991Mar07.080136.28020@ecst.csuchico.edu> ekrimen@ecst.csuchico.edu (Ed Krimen) writes:

>>I came across a utility recently that mentioned in its docs that to 
>>speed up the floppy drives, you can set them to 2ms and no verify.  
>>How reliable is this?  Does anyone out there have any experience with
>>this?

The step rate depends only on the stepper motor of the drive.
Most 5.25 inch/80 track drives will work fine at 2 ms step rate.

most 3.5 inch drives will only work down to 3 ms.


There are two kinds of "verify": the step verify and data verify.
I suggest, never to switch of the re-read after write (date verify),
cause disk drives and media are never perfect. This data verify is
something done in software only.

The step verify - a controller option: after a step the controller chip
reads in the header of the first sector it can find and compares the
track number in the sector header with the contents of the track
register; if they are equal, the step succeded; if they are different,
the controller says "seek error" to the MPU - can be switched off
safely.
It does not give more reliability if You do not step too fast for the
drive mechanic. If You have a slow stepping drive - perhaps rated at 3.5
or 4 ms per step - the step verify will relax the step timing a bit and
will therefore help to reduce the "drive X is not responding..." alerts.

hase
-- 
Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP
Hi! (Zaphod Beeblebrox)