Re: Mysterious 1541 behaviour

From: Greg King <>
Date: Wed, 23 Jan 2013 12:20:45 -0500
Message-id: <8B8C42AEA0C140CB89899847FB64A1AC@Kaiser>
Maybe, the bug is on the computer's side.  Maybe, after sending a command 
to the drive, the computer is tricked into thinking that the drive already 
"strobed" the DATA line.  So, it prematurely reads the parallel bus.

Maybe, there is a race between the two devices -- which one gets to the bus 
first?  If there is no delay, then the drive wins.  If there is a delay, 
then the computer wins -- but, it reads the bus's idle state, instead of a 
valid byte.

The drive then puts its first byte on the bus before the computer 
acknowledges the false byte.  The drive thinks that the acknowledgement  is 
for its valid byte.  So, it happily sends the second byte.

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Received on 2013-01-23 19:00:04

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