calibrator{at}freenet.de wrote:
> On 26 Jan., 09:19, "Michael J. Mahon"  wrote:
>> Since these disks cannot currently be imaged, the only way
>> to get the information is to run it on a real Apple II--there
>> a program can watch the data register shift in nibbles and reset
>> the state machine in mid-nibble!  And they aren't even really
>> nibbles (of course anything read by a Disk ][ Controller *looks*
>> like a nibble)!
> 
> Which again shows how marvellous the design of the controller
> is! And the more ingenious a design - the more ingenious the
> people need to be to fully exploit it or even go beyond it.
> 
> Surely well beyond my capabilities but I can recognize an artwork

I agree, Marcus--I use the Disk ][ Controller as a premier
example of design elegance.  Woz's experience at HP working
with early calculators (HP9100) gave him the background in
"algorithmic state machines" that set up his thinking to
produce the controller's design.

For a fun background story:

http://www.hp9825.com/html/the_9100_project.html

-michael

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