3.5" floppy drive question(s)

[Curtis H. Wilbar Jr.]

Steven Hirsch wrote:
> On Sat, 11 Oct 2008, Fred Cisin wrote:
>
>>> Also, anyone know if there if it is possible to slow the spindle speed
>>> so that 1.44M can be done on machines that only have DD data rate ?
>>> (and if so, any of the above drives capable of being slowed ?)  Would
>>> that even work ?
>>
>> Nobody has successfully used a 3.5" at 150RPM.  Yet.
>> Besides the "normal" 300RPM drives, there are some 600RPM (old Sony), 
>> and
>> 360RPM (NEC and a few others)
>
> That's not entirely correct.  Amiga 3000 and 4000 machines had a 
> Chinon drive mechanism that could run at 1/2 speed in order to write 
> hi-density formats with an FDC chip no capable of running at high data 
> rates.

Is the interface on those drives compatable enough with non
Amiga equipment such that if you had one, you could it on a
'double density' controller and do HD ?  Or did Amiga 'mangle'
the interface too far from standard ?  Did the drive adjust speed
on it's own (by detecting the HD hole) or did the Amiga have to
tell it what speed to run ?

-- Curt

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