Honeywell 6000 Series Reference Manual page 45

SECTION III
OPERATING INSTRUCTIONS
SUBSYSTEM CONSIDERA TIONS
This subsystem affords a high degree of subsystem effectiveness and data availability
to the user. Data availability depends upon the ability to remove a disk pack from a failed
disk pack drive and install it in
an
operating one. Reserve a disk pack drive as a spare so
that disk pack drives can be tested and repaired while the rest of the subsystem is online.
NOTE: The DSS190 and DSS190B have been designed to operate with the
M40S0 Disk Pack. Equivalent disk packs conforming to the
specifications of the M4050 Disk Pack may be used.
Data availability also requires the proper care, handling, and storage of the disk packs.
Disk pack identification and status labels should be affixed to the carrying case, never
to the disk pack itself. Take care not to interchange disk packs and carrying cases to keep
the information on the label (or listing) with the correct disk pack.
Bad or marginal track locations as found in manufacturing tests are noted on the disk
pack carrying case labels or listings. Marginal tracks will degrade in a few months and
should be treated as bad tracks. If more bad or marginal tracks develop, preserve this
information in a file. Identify the disk pack by its serial number and list its bad or marginal
tracks.
NOTE: Early versions of the disk pack may not have defective track
information on the label or associated listings. In any case,
defective track information is recorded on the disk pack and
will be used by the startup and format programs. These tracks
will be deallocated.
OccaSionally, dust particles settle on a disk pack recording surface and get between
the head and recording surface. The recording surface will be scratched by these particles
and the disk pack surface slowly will deteriorate. An increasing number of read errors that
can be recovered by the automatic retry program or the user retry option are evidence of
deterioration. Establish a log of recoverable errors to evaluate trends of deteriorating
performance.
3 -1 DB37