3 Dec
2002
3 Dec
'02
6:42 p.m.
Tony,
Do RL02's have a servo platter? I recall working with 300 and 600MB
multi-platter packs, on which one entire surface was reserved for "servo" to
help the head actuator establish track-to-track position. On many occasions
I'd see CDC drives load and then immediately retract heads and abort to
fault state if it couldn't read the servo platter, the net of which was
usually a 10-platter doorstop with a pretty plastic cover. ;-)
Patrick
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]On
Behalf Of Tony Duell
Sent: Tuesday, December 03, 2002 4:03 PM
To: cctalk(a)classiccmp.org
Subject: Re: RL02 Disk Cartridge Problems
While I'm not Tony, I spent some time last
year slaving over
the RL02 (and
RLV12, RL8A) printsets, and I can tell you that
the drive _doesn't_ care
what data is recorded on the disk. Fundamentally, the RL01/02 is a
fairly 'dumb' drive. Other than the sector marking magnets on the hub of
the disk, the drive is fairly undiscriminating. The only real circuits
between the read/write head and the ports on the back of the drive are
read and write amps (and write gate, etc).
Be careful. The drive most certainly uses the servo signals recorded
between the sectors. These are read by the normal heads/read ampifiers,
and then passed to the drive logic board. If those are missing/mangled,
the heads can't go on-track.
But he drive most certainly doesn't try to do anything with the user
data, including the headers and checksums. That's all handled by the
controller.
A good check would be to listen for the heads to
load into the pack. If
they're not loading, then there's no way that the data can be the source
of the problem.
Agreed. Let's see what those heads are doing.
-tony