18 Mar
2012
18 Mar
'12
8:45 p.m.
Al Kossow wrote:
I thought thr wear figure, along with the bad track replacement data was
stored on an inner track, one that is not used for user data. Certainly
the drice seeks to an inner cylinder for some reason every so often, I
assume to update the wear count.
What would be the reson for storing the wear count on every track?
Somebody should disasemble the firmware of these HP drives. It wouldn't
be iimpossible, the firmware EPROM is the only programmed IC (no other
PROMs or PALs or anyhting like that), there are no custom ICs (the disk
controller and HPIB chip are standard, the processor is a 6809) and there
are cheamtics so the addresses are all known. Then we'd know for sure
what the thing stored where...
-tony
shows the 3.5" SS (9121) as being 16 x 256
so I wonder what the 128
byte sector is, if anything
that I'm seeing
The HP drives keep some medium wear metadata on the disk, and eventually
are supposed to report to the system that the medium should be
replaced. I have a vague recollection that there's an extra sector for
that. Maybe that's the 128-byte sector you're seeing?