units. Every
minute or so, one of the drives would
puff out a small orange cloud. I was told that each
puff was a head crash. The drives would expel the
Not a real headcrash (because IMHO that implies the heads don't take off
again), but more like HDI (Head-Disk interference). This can, indeed, be
non-fatal - in fact some hard disks are designed so the heads hit the
surface when they load and then fly from there. It always worried me, but
it seems to be OK.
On the other hand, if each drive experiences HDI at 3 hour intervals (on
average), then I would suggest there's something wrong. Possibly they are
in need of filter changes or something.
Hmmm... maybe once a minute is a little exaggerated. We probably stood
there for 15 minutes and saw two puffs.
orange oxide that had been scraped from the
surface,
the head would almost always be undamaged and the
drive would keep right on going. The bad blocks
would be noticed and marked by the OS and when a pack
had enough bad blocks it would be pulled and sent out
to be resurfaced.
Minor HDI doesn't even cause bad blocks...
But the idea that bad blocks are continuously being created and then
ignored by the OS also worries me. What if there's some important data
there that needs to be read back. Of is this a WORN (Write Once, Read
Never) system :-)
I don't know. I'm not even sure what kind of machine was driving them
(although I believe it was IBM). I was hoping someone who worked at SSA
Baltimore might pipe in.