3.25-inch floppies

[Chuck Guzis]

On 1 Nov 2007 at 22:34, Jason T wrote:

> Not sure if any computer ever used them, but I remember having an old
> Akai sampler that used a bizarre "Quickdisk" format.  The sampler is
> long gone, but somewhere I have one or two of the disks, which will be
> handy should I ever try to create a magnetic media display of some
> sort.  I think they measured...2.75" (?) and held...not much at all.

I've got the 3.25" floppies and drives if anyone cares.  The drives 
are unlabeled, but I'll swear that I saw some once upon a time that 
were labeled "Shugart Venture".  There were one or two early CP/M 
boxes that used them.

I also have the 2.8" Quikdisks and can handle those too.  The Akai 
used them as did some Smith Corona word processors.  I don't recall 
the exact capacity (I'd have to look at my notes) but it wasn't much 
more than about 60K--and yes, it was a continuous spiral.  You turn 
the drive motor on, wait for it to get to speed, pulse a line that 
pulls in a clutch and you get ready to read or write the entire disk. 
The head makes a continuous spiral and then returns to the start of 
the disk and the clutch disengages.    The spiral is divided into 
sectors.

I've also got a working Smith Corona PWP-7000 that uses these.  
Curiously, it has a terminal program and speaks XMODEM at 1200 bps.  
IIRC, the CPU is something like an 8051--it's definitely not an x80 
family chip.

Cheers,
Chuck