[Coladam] another Coleco floppy drive prototype?

Richard F. Drushel, Ph.D. drushel at apk.net
Fri Jul 22 16:32:37 EDT 2005


A Coleco prototype 3.25-inch floppy drive?  I found this today at:

	http://www.old-computers.com/museum/hardware.asp?t=1&c=57&st=1

I grabbed the contents of the window that the icky Javascript gives you when
you click on the entry, and reformatted it for convenient viewing here:

	http://drushel.cwru.edu/adamcon17/coleco_325disk.jpg

I first thought it was built into the case of an Expansion Module #3, but
the EM3 still has a lid and bit of case off to the side for the ADAM reset
switch, which this prototype lacks.

I counted the number of vent louvers in the photo:  36.  I then counted
the number of vent louvers in the *other* disk prototype I found a photo
of, and used in my ADAMcon 17 PowerPoint:  it too has 36.  So, I think
they made a small run of prototype cases and were playing around with
various options.

Has anyone ever seen the external dual-tape-drive (device 09H and 19H)
that was planned (and for which support exists in SmartBASIC)?  I bet it
too would have fit in a 36-louver case like this.

Incidentally, I think an EM3 case would be *GREAT* repackaging for dual
floppy drives, or a floppy and a hard drive, just have to hack a bit for
the front bezel etc.  Now I am motivated to steal some EM3s from Richard
Clee for cannibalization and experimentation :-)

Some stuff in the accompanying description strikes me as a bit off, though:

	"I have also seen a version of the drive that fits in the larger
	bay in place of a tape drive.  That version uses the same plugs
	as the tape drive for its signal and power."

Power maybe, but signal?  The control signals coming out to the tape drive
are *NOT* ADAMnet, but are rather low-level things like motor speed,
direction, and braking, in addition to a serial data stream.  Yes, the track
select could be used for a disk side select (giving a 256K floppy, 128K per
side)...but you would need the disk controller board in the floppy add-on to
in essence be a hardware emulator for a tape drive.  I'd think it *much*
easier to just sneak a cable out through the top of the ADAM system unit to
plug into the real ADAMnet port under the power connector, and use the
existing 160K disk controller design (sans rectifier section for external
AC power supply) as a basis.  But who knows...

	*Dr. D.*

-- 
Richard F. Drushel, Ph.D.            | "They fell:  for Heaven to them no hope
Department of Biology                |  imparts / Who hear not for the beating
Case Western Reserve University      |  of their hearts."
Cleveland, Ohio  44106-7080  U.S.A.  |         -- Edgar Allan Poe, "Al-Aaraaf"



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