Date   : Sun, 27 Aug 2006 15:39:52 +0100 (BST)
From   : Greg Cook <debounce@...>
Subject: Re: writing and reading on 3.5 floppy

On Sun, 27 Aug 2006 11:12:58 +0100, Andrew Benham <adsb@...>
wrote:

> Pete Turnbull wrote:
> (lots of good stuff about index pulses and generating ready signals).
> 
> Presumably the naughty 3.5" drives only mask index pulses whilst
> the head carriage is actually in motion ?  Otherwise the 1770 FDC
> won't like the drives either.

I think that like the 8271 it will balk but the DFS can work around it.
 This possibly explains something I've seen on EDOS with a 3.5" drive,
which occasionally but repeatably left certain sectors unwritten.  I
fixed it by polling the 2791 until (status AND &A0) <> &A0 { NotReady
SpinUpComplete } before issuing the command.  This only works because
the EDOS board has a simpler timer, strictly speaking I should repeat
the command on a NotReady error, as DFS 1.21 does.

Greg Cook
debounce@...
http://homepages.tesco.net/~rainstorm/



       
       
               
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