[wellylug] VAX data floppy>USB transfer, but no FD

[Ewen McNeill]

On 2013-04-15 13:52 , Adam Bogacki wrote:
> I was later given a copy of my hard-won data on a Control Data
> single sided, double density (80 tracks/135 TPI), StorageMaster (TM)
> 1262-00 floppy disk.

You don't say what physical size the disk is: in disks of that age 8" 
wasn't impossible, 5.25" was common, and plausibly 3.5" disks were 
starting to be introduced.  I'd have expected a single sided, double 
density disk of that age (CP/M, so 1980s) to be 5.25" and have 40-ish 
tracks.

This page:

http://home.iae.nl/users/pb0aia/vax/rx50.html

suggests that it might be a VAX RX50 disk, which was single sided 80 
tracks (that they call quad density; and that was my recollection of 
single sided 80 track disks; note that "quad density" was electrically 
different from the PC "high density").

The same page suggests that if it is a VAX RX50 format disk then you can 
read it in a PC 1.2MB 5.25" drive, given custom software (ie, the u765 
-- compatible -- floppy controller is flexible enough to be programmed 
with the mode required; see generally 
http://en.wikipedia.org/wiki/Floppy_disk_controller and 
http://www.isdaman.com/alsos/hardware/fdc/floppy.htm).  The rx50 page 
above lists some possible software that might work, but I suspect 
several of those links are dead (I used 22disk years ago, probably last 
about 15+ years ago, and IIRC many of those FTP archives vanished over 
time).

Unfortunately the next bad news is that floppy disk magnetic media, 
especially 20-30 year old media, is reasonably likely _not_ to have 
survived the passage of time -- the binding of the ferrous material 
decays, the magnetism of the bits fades, and various nasties (mould, 
fungi, etc) attack the surface.  More expensive (ie, higher quality) 
older media has fared somewhat better than cheap "modern" floppy disks, 
but even with ideal storage after 20 years the chances of the disk being 
readable is very substantially reduced.

See for example Jason Scott warning (two years ago) that it was too late:

http://ascii.textfiles.com/archives/3191

for any floppy disks.  (And he's a computer historian specialising in 
older material, so he'd know.)

FWIW, I do have various PC 5.25" (1.2MB, DSHD) drives in various unknown 
conditions still sitting around (at one point I had a 5.25" quad density 
drive, but IIRC I've not seen it again in the last 15 years).  I don't 
think any of them have even been powered on in 5 years, let alone tested.

If it's especially valuable data you would be best to try a data 
recovery service.  VAX floppy disks were common enough that many of them 
should be able to read it, if it is readable.  Or perhaps find someone 
with a legacy VAX sitting around.   If it's not especially valuable data 
you're into a "hope this works" try it yourself adventure with no 
particular guarantee of certainty (and a non-trivial risk of doing more 
damage to the disk); so you should probably decide how much time it's 
worth in trying.

Ewen

PS: Even 10 years or so when I last seriously tried to get data off old 
(late 1980s/early 1990s) floppy disks, I found many of them needed a 
bunch of special care (eg, repeatedly reading sectors) to get data off 
them, and some were unrecoverable.

PPS: Found while looking for something else, a 2010 reference to a 
USB/floppy adapter to work with 5.25" drives:

http://ascii.textfiles.com/archives/2503

No idea if is still available.  And also a wiki page with more modern 
options for transferring floppy disks:

http://archiveteam.org/index.php?title=Rescuing_Floppy_Disks