External enclosure for 5-1/4 drive...

Don Y dgy at DakotaCom.Net
Sat Apr 8 22:06:19 CDT 2006

Fred Cisin wrote:
> On Sat, 8 Apr 2006, Don Y wrote:
>>> There are lots of USB 3.5" 1.4M drives.
>>> There are several SCSI 3.5" drives (most Floptical (usually SCSI) drives
>>> can do 1.4M)
>>> But I don't know of any of those that can be easily modified to support
>>> 5.25" or 8" drives.
>> If they use a conventional floppy within, the 5" and 3.5" use
>> nearly identical signals.
> I don't know of ANY USB nor SCSI 3.5" drives that DO use a "conventional"
> floppy within.

I don't know.  I only use a USB *disk* -- and even then, only
if I don't have a SCSI HA in the machine I am moving to/from.

> The common USB drives do NOT convert USB to anything even
> vaguely resembling SA400.
>> Problem would be what assumptions
>> the firmware therein makes...
> Let's solve the hardware problem first, THEN worry about the firmware.
>>> Howzbout:
>>> take a small PC, with either USB or SCSI, with appropriate drives, and use
>>> the PC itself as a slave device controller.
>> Or, just write your media on the PC and skip the interface altogether
>> :>  (that's how I handle 8")
> The original requestor asked about an external USB or SCSI 5.25".
> That MIGHT mean that he wants to hang the external drive on something
> not completely PC compatible (such as a Mac, or a Dell laptop)

And I was suggesting handling the media on another machine
that *can* handle it.  I don't have DLT's or MO's on all
my machines -- when I need to access this type of medium,
I go to a machine that *has*!  :-/

>> You can *buy* a SCSI<->floppy interface if you really want to spend
>> a lot of money on that.  It just seems like a huge waste of $$$
>> (though I am sure there are cases where it might be desirable/needed)
> I've had SCSI <-> ST506/412.
> Do you know a source for a SCSI <-> SA400/800 ?

*Some* workstation (I thought it was SPARCs) had SCSI floppies.

I also have a design for a SCSI<->4 floppy controller
that I did >15 years ago.  I can try to dig up the schematics
and sources for it.  But, I sspect many of the componentss
that it used are no longer available (?).  I know getting
the 647180's as "engineering samples" was a real problem;
and I am not sure the 5380 (5830?) is even manufactured any
more...  I was tickled that the PCB was exactly the size
of a 5" floppy (though it was designed for 8" media
originally -- a few extra wires in the diskette interface
cable and support for the "door lock", IIRC)

By far, the easiest thing to do would be a USB<->floppy
nowadays... microcontroller + floppy controller/COMBO
(unless you want to pinch pennies and do an Apple style
floppy controller implemented in software...)

I'll see if I can find my drawing set and any paperwork
(contractual obligations) governing it.

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