mysterious "failed to complete operation" disk errors

[David A. Moon <Moon at MIT-AI>]

The microcode bug that caused this is fixed in UCADR 841.  I noticed that several
routines were calling DISK-RUN when they should have been calling DISK-READ-WIRED
or DISK-WRITE-WIRED, and consequently failed to get microcode error recovery (and
in fact were led into the buggy part of the microcode fixed in 841.)  Patch 78.23
fixes the two functions in the system with this problem.  File system maintainers
and anyone else who does disk I/O should check their code.  If it calls the wrong
function, fix it.