24 Sep
2005
24 Sep
'05
9:52 a.m.
On 9/23/2005, jpero at sympatico.ca wrote:
Look for Epson 3.5" drives, they are plastic,
have to remove the
metal sleeve to see this black plastic chassis, also the head sevro
is stepper with tiny, tiny fine toothed rack (thin bronze) & prinion
(also tiny dia). Not suitable for heavy use.
Although not very solid, Epson was the only 67.5 TPI 3.5" drive that I
could ever find. (disk format of Geneva PX-8)
On Sat, 24 Sep 2005, Chuck Guzis wrote:
Portable Smith Corona word processors used a 2.8"
drive that worked the
heads via a follower than ran in a spiral groove molded into a plastic
disk that was driven by the spindle motor through a clutch. Basically,
pulsing the clutch caused the head to move in a continuous spiral
pattern from the beginning of the diskette to the end. Sort of a
windshield-wiper auto-completion mechanism. You could read or write the
entire diskette (about 60K (MFM), if memory serves), but nothing less
than that. A gutless wonder if there ever was one. It was actually
pretty robust.
I remember about 20 years ago that TEC (NOT TeAc) announced a
2.9" drive with a spiral track. (as well as some 720K 2.9" ones)
Is that what they were using?
There was also a Weltec 5.25" drive that ran at 180 RPM,
in order to do 1.2M with XT at 250K data transfer rate.
The Dysan 3.25" was kinda neat. Dysan bet the company that the
"shirt pocket" disk (3", 3.25", 3.5", 3.9") that would
succeed
would be the one with software availability. So, they overextended
themselves creating a software publishing/distribution company
providing MOST of the big popular software titles on 3.25".
'Course George Morrow said that the solution was to cut a deal with
the clothing industry to enlarge shirt pockets to 5.25" or even 8".
My favorite weird drive was the Amlyn. It was before the AT came out.
It used a "proprietary" 8 bit ISA controller that had a 500K data
transfer rate (could also be used for 8"). It used a cartridge that held
5 600 Oersted disks (total of 6M), with a few extra holes punched in
corners of the jackets, and could change disks from the cartridge under
software control. One of mine is now in Sellam's collection; NO idea
where the other one is.
And, of course, there was always the Lisa "twiggy". 600 oersted 5.25",
with an extra read/write access oval to make sure that EVERY disk got
thumbprints on it.
--
Grumpy Ol' Fred cisin at xenosoft.com