14 Jun
2010
14 Jun
'10
7:55 p.m.
Hi folks,
I'm just reviving a completely misaligned RK05 drive. I want to get it fully up and
running and
tested before I use an alignment pack. So I started debugging and got it to the point
that I can
play with the formatter.
Here comes the question: The formatter (RKLFMT under OS/8) threw MANY CRC errors when
reading back
the freshly formatted disk. Changing the head cables at the drive proved that the problem
is only
with one head i.e. the failures change "side" when you change the head plugs.
Now I ran the test several times. With random failing disk addresses. And they decreased
and
decreased... Now I've run two error-free formatter rounds.
Could it be possible that new data on new tracks (keep in mind that the drive is actually
misaligned
by means of mechanical alteration!) suffers from interference from old tracks? That's
the only
reason I can see for this kind of behavior.
I think that's unlikely. There is a tunnel erase head which essentially
wipes out any old data that might be picked up by the read head.
Do you know if the heads are good? I've had at least one RK05 head that
tested OK electrically, looked clean, but which procuded no signal
On the other hand that would mean that I'd have to degauss the pack before I ever
could use it
reliable again.
Since there's no servo infromation or anything like that on an RK05 pack,
there is no reason why you can't degauss it.
Do yuo have any more packs? If so, try formatting another one. If that
passes with no CRC errors, it would appear to be a head problem which has
got better as the drive was used. If you get CRC errors at first which go
away if you format it a few times, it would apperar to be your suggestion
of old data causing problems.
-tony