30 Mar
2023
30 Mar
'23
2:26 a.m.
Is there a list of floppy disk drives which could read and write both 3.5"
1.44mb and 720k diskettes?
A product line of musical instruments (General Music/Ahlborn-Galanti) I
service use 3.5" 720K DD floppy disk drives.
I've never had any problems formatting or backing up data files prior on
other instruments. Tuesday, I attempted to format a floppy disk using the
instrument's internal FDD prior to backing up the data files. After the
format an error appears "corrupted data". Which could mean so several
different things from a bad floppy drive, etc.
I currently have one box of Sony MFD-2DD 3.5" 720K Double Density Floppy
diskettes which were bought new a few years ago, kept in their box, and
stored in a dust free place. I've used them prior for the same purpose with
no problems.
I'd like to be able to verify at home that the diskettes haven't all
suddenly gone bad.
Thanks
Don Resor
10:24 a.m.
On 3/30/23 09:24, Ethan O'Toole via cctalk wrote:
> Is there a list of floppy disk drives which could
read and write both
> 3.5"
> 1.44mb and 720k diskettes?
Absent any alignment issues, or dirty heads, just about any HD drive
(e.g. Teac FD235HF) is equally facile in both DD and HD media. Quite
often, a DD-only (e.g. Teac FD235F) drive will have performance inferior
to that of the HD-DD drives.
Other issues that might crop up in reqplacement, such as READY on pin 34
versus DISK CHANGED, does have to be taken into account.
--Chuck
10:48 a.m.
On Thu, 30 Mar 2023, Chuck Guzis via cctalk wrote:
Absent any alignment issues, or dirty heads, just
about any HD drive
(e.g. Teac FD235HF) is equally facile in both DD and HD media. Quite
often, a DD-only (e.g. Teac FD235F) drive will have performance inferior
to that of the HD-DD drives.
Other issues that might crop up in reqplacement, such as READY on pin 34
versus DISK CHANGED, does have to be taken into account.
some of the exceptions:
The drives in many IBM PS/2 machines don't seem to have a media
sensor, so they can't tell the difference between "720K" and
"1.4M" disks.
"720K" is about 600 Oersted, and "1.4M" is about 750 Oersted, so they
are
close enough that sometimes one can get away with using the wrong one.
There once existed single sided drives. Such as the original Shugart SA300
They were used in early Gavilans, but were replaceable with double sided,
especially the SA350, which could use the Gavilan's custom SA300 bezel,
Epson Geneva PX8 was 40 cylinders, intead of 80, with 67.5tpi, instead of
the usual 135tpi.
"2.8M" will also work, it has a media sensor for te ED disks.
The original Sony FULL height drives were at 600RPM, and had a different
interface.
The Tandy Portable Disk Drive, for the model 100, was weird and a half.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
6:24 p.m.
On 3/30/23 10:48, Fred Cisin via cctalk wrote:
The drives in many IBM PS/2 machines don't seem to
have a media sensor,
so they can't tell the difference between "720K" and "1.4M"
disks.
"720K" is about 600 Oersted, and "1.4M" is about 750 Oersted, so
they
are close enough that sometimes one can get away with using the wrong one.
Those PS/2 drives often have peculiar IBM-specific interfaces. For
example, some are 40 pin instead of 34. Or power is shared on the same
cable as signals, etc.
You're not likely to consider them.
There once existed single sided drives. Such as the
original Shugart
SA300 They were used in early Gavilans, but were replaceable with double
sided, especially the SA350, which could use the Gavilan's custom SA300
bezel,
Epson Geneva PX8 was 40 cylinders, intead of 80, with 67.5tpi, instead
of the usual 135tpi.>
The original Sony FULL height drives were at 600RPM, and had a different
interface.
The Tandy Portable Disk Drive, for the model 100, was weird and a half.
But none of those are high-density drives.
I'll add one of the issues may be drive-select setting for non-PC
devices. It's easy enough to get around, however.
--Chuck
6:42 p.m.
Yes, those are not the drives you want.
None of those exceptions.
I was merely listing sone of the weird ones to avoid (or use for weird
stuff)
IF I remember correctly (unrefreshed dynamic wet-ware RAM), 34 pins of the
40 pins of the PS/2 drive were the same, and the other 6 pins had the
power. I think that you could simply take a 40 pin cable, connected to
the drive, and split off those 6 pins, and crimp a 34 pin connector on the
remainder for the FDC end. Or, the other way around - a friend had
generic drives in his PS/2. But, I have no idea where my notes went to,
for the pinout of which of the 6 were which, and/or disk/change VS Ready,
how they did the drive select, and possibly a few other minor weirdnesses.
Pinout for PS/2 should be readily available.
generic drives are still readily available and cheaper, so leave the PS/2
drive to the people with PS/2s.
On Thu, 30 Mar 2023, Chuck Guzis via cctalk wrote:
On 3/30/23 10:48, Fred Cisin via cctalk wrote:
The drives in many IBM PS/2 machines don't
seem to have a media sensor,
so they can't tell the difference between "720K" and "1.4M"
disks.
"720K" is about 600 Oersted, and "1.4M" is about 750 Oersted, so
they
are close enough that sometimes one can get away with using the wrong one.
Those PS/2 drives often have peculiar IBM-specific interfaces. For
example, some are 40 pin instead of 34. Or power is shared on the same
cable as signals, etc.
You're not likely to consider them.
There once existed single sided drives. Such as
the original Shugart
SA300 They were used in early Gavilans, but were replaceable with double
sided, especially the SA350, which could use the Gavilan's custom SA300
bezel,
Epson Geneva PX8 was 40 cylinders, intead of 80, with 67.5tpi, instead
of the usual 135tpi.>
The original Sony FULL height drives were at 600RPM, and had a different
interface.
The Tandy Portable Disk Drive, for the model 100, was weird and a half.
But none of those are high-density drives.
I'll add one of the issues may be drive-select setting for non-PC
devices. It's easy enough to get around, however.
--Chuck
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days inactive
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5 comments
4 participants
participants (4)
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Chuck Guzis -
D. Resor -
Ethan O'Toole -
Fred Cisin