Ref: 11640086
Title: Tape Drive Errors During Backup and Restore
Date: 8/31/90

Copyright 3Com Corporation, 1991.  All rights reserved.

Messages such as "Tape Drive Error" occurring during backup
operations and "Unrecoverable data error" occurring during
restore operations can have several different causes.  Either of
the errors can occur as an intermittent problem with specific
tapes as they age with use.  When the errors become more
frequent, it is usually an indication that either the tape is
wearing out, the heads in the tape backup unit are not clean, or
that there is a problem with the tape unit itself.

Each time the tape is used for a backup, some of the ferrous
material with which the tape is coated wears off.  The tape
becomes more and more susceptible to intermittent errors.  If the
tape drive heads are cleaned after every eight hours of use,
tapes should last for approximately six months for once-a-week
backups.

If the number of errors suddenly increases, check the following
list for the cause of the problem:

Substandard tapes--Use of tapes other than those recommended by
3Com can lead to earlier than normal tape failure or loss of data
on tapes that have already been written during system backup.

Dirty tape drive heads--If failures occur on relatively new tapes
as well as on tapes that have been in service for a period of
time, the heads should be cleaned.  Clean heads at least once
each month, or after approximately eight hours of use.  Use a
tape drive head cleaning kit, or cotton swabs and Freon ST, or
90% isopropyl alcohol.  Failure to clean the heads properly will
cause damage and shorten their useful life.

Worn heads--If cleaning the heads does not help, the tape drive
may have worn heads.  If you suspect this, take the tape unit to
your network supplier for diagnosis.  The expected duty cycle for
tape heads is 1200 to 1600 hours of actual use with recommended
tapes.
