reading legacy floppy disks

[Evan Leibovitch]

Dave Mason wrote:
> I have a bunch of 7" (yes, 7-inch) double-sided, high density (something over 1MB per disk) floppies that I want to try to read.  I really just want a dump onto a CD.  I can decode the format (UCSD P-System) and extract the data.  These were probably last used 20 years ago, but have been stored fairly carefully.
This puzzled me. I've used 8" floppies (in PDP-11s) and 5" floppies 
(Apple ][s, Commodores and the original IBM PCs). I've never heard of 7" 
ones.

I don't recall the P-system being used on minis, and I don't recall 8" 
disks being able to store more than a few hundred KB, so my guess is on 
the 5" format. Then again, if the disks are that old, they're also from 
the days of when hard-sectored disks (16 holes in the media) were 
compatible with soft-sectored stuff (1 hole).

Finding 5" drives shouldn't yet be too hard; finding 8" drives will be 
quite a bit harder. Finding one that supports your sectoring scheme, and 
having your disks have held their magnetism long enough to give you 
something readable.... if you can get it to work, immediately go out and 
but a lottery ticket. :-)

> (P.S. I know this is kinda off-topic, but I don't know of a more-knowledgeable Toronto group.)
>   
I won't spread that to the folks at u-u if you don't  ;-).

- Evan

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