[Coco] question about 3.5 inch floppies

[Gene Heskett]

On Monday 03 August 2009, Stephen Adolph wrote:
>Hi,
>
>Another dumb question-
>
>A 3.5 inch drive will work like a 720k drive simply by placing a DD
>(720k) disk into the drive, right?
>
Generally, yes.  Unforch, finding DD disks can be frustrating.  Taping over 
the HD hole usually doesn't work as the switch in record drive currents then 
results in a weak recording, one that may or may not be readable an hour 
later.

>So, to use a 3.5 inch floppy with Nirtos-9, one merely needs to have
>it be plugged in, and make sure to use 720k floppies.   The disk drive
>will operate correctly. (?)

If the descriptor is properly dmoded for 720k, usually yes.

>Interestingly, I have 3 different versions of the same Panasonic
>JU-257.  Only one of them can be selected to be drive 0 or 1.
>
>I think I have read that, in the coco, you want to use hard drive
>selects...no twisted cables.

That is best.  The drive cable adapters can, if all traces are there, be where 
the drive select signals are swapped around, allowing one of the fixed at 
drive 1 drives to be used as 0 or 2.  Terminations on 3.5" drives could be a 
problem too, and one should check to see if the pc's twisted cable also 
somehow enables the terminators for drive 0, out on the twisted end of the 
cable.  Its not something I have attempted here, my drive 0 is a 5.25, 360k 
drive, 2 is a 720k 5.25, and one is whatever is plugged in at the time, boot 
default for drive 1 is a 720k here.

>thanks, Steve
>
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