8" floppy system needed to recover old game data

[Lawrence Wilkinson]

On Sun, 2005-10-09 at 10:53 -0400, Brad Parker wrote:
> I'd get read errors and pull out the floppy and there would be a literal
> clear ring where the head had removed the oxide.
One of my first projects after uni c. 1984 was to make a controller for
a metal forming line.  We used a Little Big Board (IIRC) with an 8" SSSD
drive, an ADM-3A and Turbo Pascal!

Just before I moved to England in '94 we got a call from the company to
say that they had sold the line and it was all going to be dismantled,
but they needed it working for another month, and it had just stopped
booting up.

Sure enough, the disk had a nice transparent ring on it.

Amazingly, they managed to find the backup disk we had given them in
'84, and we got it going again.  I never heard any more.

I'm not sure whether the wear took place only at boot time (since the
drive wasn't used at other times) or whether the head wasn't unloaded
enough to prevent some wear.  10 years for one disk isn't too bad.
-- 
Lawrence Wilkinson                                 lawrence at ljw.me.uk
The IBM 360/30 page                       http://www.ljw.me.uk/ibm360