[Coco] 3.5" drives

Robert Emery theother_bob at yahoo.com
Sat Aug 21 07:54:38 EDT 2004


No, that's not right... most (>95%) of 3.5" floppy drives are hardwired as
drive B, or drive 1 to the CoCo. By themselves on a PC floppy cable (with a
twist) the drive select lines are swapped... and no, the cable-twist apparently
does not work for CoCo controllers.

Under Disk Basic 1.1, to access the second side of drives 0 and 1 as drives 2
and 3 respectively, use POKE55455,65:POKE55456,66. On a coco1 or 2 this
requires a 64K CoCo in all-ram mode.

Bob


--- "James C. Hrubik, Sr." <jimhrubik at earthlink.net> wrote:

> James, you should be able to add the 3.5 in place of the single-sided 
> drive.  Most of the 3.5s are hardwired as "A" drives, and if your 
> double-sided 5.25 is jumpered as "B" or D2, you should be good to go.  
> RSDOS will see the 3.5 as a 35 track single-sided drive.  OS9 will use 
> everything available.  OR, if you don't mind the way it looks, and can 
> manipulate the jumpers, you could have a 5.25 SS, 5.25 DS, and 3.5 on 
> the system.  I've run 3 drives temporarily (it's ugly to look at!) with 
> the case open for setting up new OS9 boot disks.  Watch the cabling, 
> though.  And you'll want DSDD disks for the 3.5 (but you can fake it 
> for a while using tape on the HD disks).
> 
> 
> On Friday, August 20, 2004, at 11:14  AM, James Dessart wrote:
> 
> > I'm interested in putting a 3.5" drive on my CoCo, since 3.5" floppies 
> > are
> > still available in stores, and I do have a couple of Macs that can
> > read/write to them (even in PC format).



		
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