I've finally got it figured out. The earliest thing that had
8" floppies which I dealt with was an IBM drive (very slow step rate,
with Geneva gears driving the leadscrew). That one was 77 tracks, 26
sectors per track, 128 bytes per sector -- but it was being used for
storing punched card images, so there were only 80 bytes stored in that
128 byte sector -- taking the *effective* capacity down to your 156k.
Yep -- I've dealt with some hard sectored ones as well -- and
they held more, because without the soft sectoring overhead, they got 32
128 byte sectors per track.
Even the 3.5" floppies use a timing hole -- it is just on the
hub in the drive, which is keyed to the floppy.
But most of my use of the 8" floppies was either at 500K (Double
Sided, Single Density) or at 1MB (DSDD).
So did I. It gave me enough experience so when a friend at the
next building at work got a pair of unix boxen to administer (for
e-mail), I was able to show him some tricks, and that resulted in him
talking his boss into giving me a free account, so I could do things
like port net based utilities to the (rather weird) BBN C70 (10-bit
bytes, 20-bit words, 40-bit longs. :-)
The common compress program (LZW algorithm) would work fine on
text files, but blow up spectacularly on binaries. However, there was a
compress program from the OS-9 UGL which had tuning parameters for
10-bit bytes, and that one worked beautifully. It saved his rear a few
times while doing backups.
I'm trying to remember what OS-9 used for a pipe symbol, instead
of the '|' now. :-)
Oh -- you mean the sandwichbox ones -- half the height of the
LX and several others of the small square box computers. I've already
got several drives, including one QIC-150 in the Solbourne box (a
semi-clone of the SS2 boxen, but faster and neater). From here, I can
see four of the sandwichbox enclosures -- one disk, and three CD-ROMs,
one of the "lunchbox" enclosures with a 1GB 5.25" full height in it) and
two of the later unipack enclosures -- one SCA disk, and one Exabyte
8505XL tape, and below those two, a 6-drive MultiPack (one of three of
those that I have).
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I've been using DFSee to recover NTFS drives and partitions,
www.dfsee.com. Registered users can get help from the author via
newsgroups or email. I've had several instances where Windows nailed
the partition tables and boot sectors on my 250 G work drives, I was
able to recreate them and recover my data with little or no loss. The
author now provides a bootable CD disk image to registered users so
even if the machine is in a nonbootable condition, you can poke around
on the disks.
Downside is you HAVE to know what you are doing, patching disk
structures isn't for the tyro. The DFSee author has a number of
tutorial links on his site, these may or may not be enough to help you
out. He's made the latest versions a lot easier to use with menus,
before, it was strictly a command-line thing. You can use the program
to clone a drive so you can noodle around without messing with the
original, one way to develop the knowledge. Takes about a day and a
half to clone a 250 G drive, just did it last weekend.
Ontrack (ontrack.com) is a big dog in the data recovery business.
These days they seem to have application you can d/l and run to
analyze the data and show what can be recovered. If you think it's
worth it you pay (ISTR $79).
Years ago a client of mine paid Ontrack $4000 to recover financial
data from a failed server disk rather than put a daily tape in the
tape drive I set up for him (and he paid for).
Put another (new) drive in its place, and rebuild it from your backups.
If you don't have backups, you most likely have just got lesson #1 of
computer work: backup early and backup often. Most people don't need
more than one such lesson.
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