30 Apr
2024
30 Apr
'24
8:06 p.m.
Thank you for trying to help. My situation is unusual at best and I'm
apologize for the extra bandwidth my question is causing.
I am formatting the floppies in an HP-9114A battery operated floppy
drive connected to an HP-41 calculator over the HP_IL serial interface.
The HP9114A drive uses a modified Sony 3.5" floppy drive running at 600
RPM instead of the normal 300 RPM. This is an extremely unusual
configuration that is different from any PC/MAC/Commodore/Amiga situation.
I have been working with floppies since 1980. I have written floppy low
level formatters (WD1771 & WD1791 controllers). I currently use a
greaseweasel connected to a pair of 8" drives to create and copy
floppies for the RX02 on my PDP-8. I fully understand about density and
number of tracks, sectors per track, tracks per inch, fm/mfm/gcr
encoding, etc.
I'm sure if I tried enough 1.44MB floppies I would find a few that might
work on the HP9114A drive. However, that was not my question.
I am looking for a dozen or two Double Sided, Double Density 720K
(formatted capacity) disks to use with this drive.
I appreciate all of the suggestions and help but let's keep the
bandwidth down and take any floppy compatibility discussions off of the
group.
Than you again everyone for offering to help,
Mike
On 4/30/2024 2:41 PM, Wayne S wrote:
What errors are you seeing?
Sent from my iPhone
> On Apr 30, 2024, at 12:29, Mike Katz via cctalk <cctalk(a)classiccmp.org> wrote:
>
> I have tried bulk erasing 1.44 MB disks and they still won't format in the
HP9114A battery operated HP-IL Floppy Disk drive.
>
>> On 4/30/2024 12:20 PM, Joshua Rice via cctalk wrote:
>>> On 30/04/2024 18:08, Anders Nelson via cctalk wrote:
>>>
>>> Having grown up with 1.44MB 3.5" floppies, I have a question: is it
>>> possible to use a 1.44MB disk and just format it as a 720K disk?
>> I think it's entirely possible. I'd definitely format them in a 720kb
drive though to be extra safe. Though original 720KB disks written/formatted in 1.44MB
drives seem perfectly cromulent from my experience.
>>
>> However don't quote me on it, The only double density drives i have are super
early Sony ones built in 1982 and they get pampered with NOS 720kb media (with the sliders
sellotaped open because no auto opening shutters on my drives!)
>>
>> Josh Rice