29 Oct
2024
29 Oct
'24
12:09 p.m.
On Tue, Oct 29, 2024 at 7:00 PM Fred Cisin <cisin(a)xenosoft.com> wrote:
On Tue,
29 Oct 2024, Tony Duell via cctalk wrote:
True. I prefer to talk about 'cylinders' though.
Sure. I was just adding information for completeness.
That little portable drive? I have one with a failed 6303 CU chip,alas.
Wasn't one version of the portable drive for the TRS-80 model 100 also
40 cylinder? And they were certainly used in some music synthesisers,
etc.
360K
drives (40 track) have tracks 48 tpi. (Early on, Shugart SA400, and
For the pedants, the IBM 360K format is 80 track.
40 cylinders, each
of 2 tracks, one on each side of the disk.
point taken.
I should have said "Tracks per side" There were a few 100tpi 5.25" drives.
Annoying because they couldn't
read 40 cylinder disks even if you double-stepped them. Didn't
Commodore use them in the 8050?
Yes, but this was in response to 360K/1.2M issues. I have had some 100TPI, both Micropolis and Tandon
TM100-4M
One of the 100tpi Tandon drives is mislabeled as being TM100-4, without
the criticaally important 'M'
ARGH!
I wonder if the same heads (with different diameter pulleys on the
stepper motor) were used both 96tpi and 100tpi drives in some cases.
You'd get away with it if the head was made for 100tpi I think.
3.5" drives tend to be 80 cylinder, 135 tpi.
There were a few 40
cylinder 67.5 tpi drives with, I assume, a wider head. I've never seen
one in a PC though.
Not in s PC, but Epson Geneva PX-8 used one. Shouldn't ever have problms with it. But, if the
disk is damaged,
would the wider track be able to survive a little more damage?
I've had floppy disks that will reliably format and work in 40
cylinder drives (data readable at least a year later) but which threw
up errors if you tried to format them in (standard data rate) 80
cylinder drives. I never got to the bottom of that.
-tony