[Coco] Need new disk drive...

[Gene Heskett]

On Thursday 18 September 2008, Phill Harvey-Smith wrote:
>Gene Heskett wrote:
>> On Wednesday 17 September 2008, Chuck Youse wrote:
>>> On Wed, 2008-09-17 at 21:25 -0400, Gene Heskett wrote:
>>>> That controller MAY have a Fujitsu 8877 FDC chip in it.  This chip is
>>>> one of the few that can be used at 500 kilobaud data rates, allowing
>>>> DSDD floppy drives to be used at 1440 kilobyte size.
>>>
>>> Am I missing something?  Double-sided double-density 5.25" drives are
>>> 360K, no?
>>
>> If set for 40 tracks, double sided in the os9 descriptor then yes.
>
><pedantic mode>
>Or 80 track single sided.....as IIRC some early Atari ST machines used,
>at least here in the UK.
></pedantic>
>
>>                                                                But I
>> believe that chip can have the high speed data rate hack applied, which
>> means the nearest $25 3.5" 1.44 meg drive with HD diskettes can be used in
>> it.
>
>But then wouldn't that be DSHD ? Double sided, High density ? Was this
>what was sometimes refered to as Quad density, or was that 80 tracks as
>opposed to 40 ?
>
I *think* the quad density stuff, short lived, would have been the 1 megabaud 
2.88 meg 3.5 format, although I have a box of QD 5.25 disks as well.  I used 
them as 720k disks but I think they were intended for the 2.4 meg version of 
the drives such as the Teac 55-G family, which would have been a 1 megabaud 
data rate version of the 360 rpm 80 track DS disk, normally recorded at 500 
kilobaud.
 
>Cheers,
>
>Phill.
>
>
>
>--
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>Coco at maltedmedia.com
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-- 
Cheers, Gene
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