Exabyte warnings, write retries

[katz at rpal.com]

In article <1990Oct7.214035.20639 at rice.edu> lbd at alux4.att.com writes:

> We have a 4/490 running 4.1, on which we run incremental and full dumps.
> The dumps all seem to run just fine, but we get repeated warnings:
> 
> Aug 28 13:35:49 latin1 vmunix: st1:  warning, the tape may be wearing out or
> Aug 28 13:35:49 latin1 vmunix:       the head may need cleaning.
> Aug 28 13:35:49 latin1 vmunix: st1:  write retries= 1135 (60.3%), file= 0, block= 1880
> 
> The number of retries is usually in the same range, but the percentage of
> retries varies, from 6% to 80%.  I realize that this is a warning, so it's
> not hurting my dumps, but it is a pita, and my messages files fill up
> awfully fast.

You have found a bug in OS4.1.  There is a patch available.  The following
is from the README of the patch tape:

------------------------------------------------------------------------
Patch-ID#  100134-01
Keywords: video tape 8mm tape
Synopsis: 4.1 st: warning tape may be wearing.... on Exabytes
Date: 18/July/90

SunOS release: 4.1_PSR_A
Topic: BugId's fixed with this patch: 1042822
Architectures for which this patch is available: sun4_490

Problem Description:

Premature "st?: warning tape may be wearing out or...." caused by high
soft error rate at the beginning of new 8mm video tape.  Exabyte's Exatape
does not seem to have this problem.

Morry Katz
Rockwell Science Center
administrator at rpal.com (machine administration issues)
katz at rpal.com (other)