[Coco] Re: Bellingham User Group Stuff

Theodore Evans (Alex) alxevans at concentric.net
Tue Feb 3 23:21:52 EST 2004


On Feb 3, 2004, at 5:26 PM, Gene Heskett wrote:

> On Tuesday 03 February 2004 17:57, Boisy Pitre wrote:
>> I suspect that bit 1 of byte $10 in LSN0 is not set. It should be,
>> indicating to the driver that the disk is formatted as a 96tpi disk.
>>
>> Look at offset $10 of LSN0 of the disk image.  It should be $03, not
>> $02.
>>
>> Boisy
>>
> That would depend on whether he wrote them to a 5.25", or to a 3.5"
> diskette.  The 3.5 was 135 tpi from the gitgo, so that bit should not
> be set for a 3.5" formatted disk as there is never a chance of a tpi
> miss-match there.

I have seen 40 track 3.5" floppy drives.  They are exceedingly rare.  
No consensus has ever been reached as to whether to set or clear the 
"96 tpi" bit for 3.5" drives.  No doubt there are a significant number 
of people who merely used the 720k 5.25" descriptor for their 3.5" 
floppy drives.  Basically if their descriptor has this bit set it 
should be set and if not it should be cleared.  Unfortunately this has 
caused some conflict when exchanging 3.5" floppies.




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