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mutterminder

SCSI Floppy Disk Drives

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I work with a lot of legacy computers.  This is an Avionics shop environment, so we can't just upgrade to modern hardware as we have to use whatever was specified at the time of design.  Consequently, this means that it is often necessary for me to transfer data to modern computers via 3.5" floppy disk. (Some of our equipment still had 5.25" inch floppies.)  As modern PC's don't have floppy disk controllers, we have purchased external USB floppies.  These work most of the time, but the floppy drive mechanisms are inferior to legacy drives and they are slow and error prone.  Because of this I have been trying to find a more robust solution to work with my modern PC running Windows 10.   We have access to new old stock of of TEAC FD-235HS -711 SCSI Floppy disk drives, these consist of a FD-235HF-3700 floppy drive mechanism with a TEAC FC-1 SCSI floppy disk controller bolted on.  I was able to install this drive into my PC and I can access it with and Adaptec SCSI  card.  However,  I have been unable to get the drive to recognize HD floppy disks.  It won't read or write in HD format.  If I format them on an older machine as 720K normal density, then the drive has no problem reading and writing to the disk.  

 

I do not have documentation for these drives.  I have been able to find some documentation for the FC-1 which also discusses the floppy disk jumpers, however, it is for a different floppy drive mechanism with a different layout.  Since I know there are a lot of smart people who frequent these forums,  I thought I would post this here.  I've attached a picture of the jumper settings as they are set now.  They are all factory default except the SCSI ID has been set to 2.  If anybody has any idea what may be going on here, please let me know.  From what I've been able to find, this should work, but I've tried two brand new drives and I have the same issue with both. Thanks.

TEAC FD-235HS-711.jpg

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Another curious thing is that with a 720K disk installed, if I try to format the disk in Windows 10, the only option that Windows will give me for media size is 640K.  If I attempt to format the disk at this point, the formatting fails.  However if I install a 720K formatted disk I can read and write to it no problem.

 

On further research on the FC-1 SCSI floppy interface that comes with this drive, it looks like it could actually control up to three floppy disk drives. It should be able to work with 720K, 1.44M, or 2.88M.  Normal density, high density, or enhanced density.  Perhaps the problem is the SCSI cards I have tried?  I have tried the Adaptec 2940UW and the Adaptec 29160.  Neither of these officially support Windows 10 although I've been able to make them work.   

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Are these IBM PC clones, or something else entirely?

 

If the former, you might consider something like a laplink cable, or getting a parallel (or scsi external) zip100 drive. These would not be permanent installations, just used to get data into and out of your legacy, "certified" hardware deployments.  (Use the 'guest.exe' program that came with the external zip drive with a real bootable diskette, then copy data at 100mb a shot.) 

 

Another possible choice on a modern system, is an LS120 (Superdisk) drive.  While intended to be a contender for iomega's zip disks, it offers full back support for 3.5" IBM formatted diskettes, and lives on an IDE interface. 

https://www.ebay.com/itm/NEW-Digital-Research-internal-SuperDisk-Drive-LS-120-DRLS120-FACTORY-SEALED/174033397996?hash=item288532e8ec:g:Tj0AAOSwZCFdgIUk:sc:USPSPriority!67570!US!-1
(supposedly new old stock. There are cheaper offers, but those are refurbs.  You do not need the 120mb media. It can read and write 3.5" diskettes. It does so crazy fast too.)  I have tested iomega's internal zip100 drives on sata-IDE adapters, and those work fine. I suspect the superdisk would too.  Dunno if win10 would know how to deal with it properly though.

 

edit:
Some cats at vogons have gotten one working in win10 with some caveats.

https://www.vogons.org/viewtopic.php?f=46&t=50435

 

One thing you should check though, with your old-stock scsi units, is for the presence of the switch mechanism in the left-hand side of the door. That is what detects if the disk is high density or not.  If there is no little switch there, then the drive is low density, and will NEVER read a high density diskette.

 

 

Edited by wierd_w

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Thanks, for the reply.  If you look in the picture, the drive is a TEAC FD-235HF according to TEAC's documentation this is an HD drive.  It does have the density switch installed.  I'm starting to believe it's an issue with Windows 10.  I haven't really had a chance to try this setup in an older PC with Win XP or earlier, of course those older PCs tend to have floppy disk drive controllers so I wouldn't have to try this workaround.  The LS-120 route might be worth pursuing if it can be made to work in Win 10. The only problem with that option is my company will not allow purchases from ebay.

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11 hours ago, mutterminder said:

Thanks, for the reply.  If you look in the picture, the drive is a TEAC FD-235HF according to TEAC's documentation this is an HD drive.  It does have the density switch installed.  I'm starting to believe it's an issue with Windows 10.  I haven't really had a chance to try this setup in an older PC with Win XP or earlier, of course those older PCs tend to have floppy disk drive controllers so I wouldn't have to try this workaround.  The LS-120 route might be worth pursuing if it can be made to work in Win 10. The only problem with that option is my company will not allow purchases from ebay.

How about amazon?

 

https://www.amazon.com/Panasonic-LS120-Beige-Bezel-LKM-F433-102/dp/B0045JPK7K/ref=sr_1_50?keywords=LS120&qid=1571056034&sr=8-50

 

Or NewEgg?

https://www.newegg.com/p/2M6-000V-00004?Description=LS120&cm_re=LS120-_-9SIAA7W8VH8393-_-Product

 

 

EDIT

 

I also found this, concerning your TEAC SCSI units.

 

https://hxc2001.com/download/datasheet/floppy/thirdparty/Teac/FC1/HW_HS_1100.PDF

 

It appears to be a very detailed user manual for the scsi controller and disk combination you have, and includes the jumper info.

 

On Pg11, it discusses the various formats of disk the drive and controller supports, and what "mode" to use.  For high density diskettes, this would be the "2mb" mode.  They are clearly referring to "unformatted capacity" for size.  Their table lists 1.20mb, 1.44mb, and 1.62mb formats in this configuration category. (I suspect that the 1.72 variant of the microsoft distribution formatting is not supported?)

  Jumper configuration information begins on Pg42.

 

It looks like the controller expects to be told what kind of floppy is inserted or something. (PG40)

There are two cited methods for getting the drive/controller to identify the disk type as the 2mb variety, and they both seem to involve scsi messages being sent.

 

 

 

I am beginning to think that the LS120 is the better option--

 

Edited by wierd_w

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You can build a modernish system using parts from the previous generation (around 2009-10)... my PC runs Windows 7 yet still has a floppy controller... it might just be cheaper and easier to just use PC with a real floppy controller.

 

 

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Hmmm...

 

 

Outside the box solution:

 

One of these inexpensive backplanes...

https://www.mouser.com/ProductDetail/Advantech/PCA-6105P3-5A1E?qs=HovGnFcXeQCTm1XmLEYbdw%3D%3D

 

With one of these SBCs (which has an FDC!)

https://www.bsicomputer.com/products/wsb-h610-full-size-cpu-card-2864

 

That would give you a modern class computer with a real floppy disk controller.

It would also give you some ISA slots for whatever you might want to put in there.

 

You would need a special chassis though.

 

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