Running an EXPORT NODE over the weekend, I received this error message:

     ANR5364E Record sequence error on device 05A4.

The help file for that message says this:

  EXPLANATION:  During processing of a tape volume, the record tape
  number read does not match that expected by the drive.

  SYSTEM ACTION:  The server marks the volume in an I/O error condition.

  USER RESPONSE:  This failure may be due to a hardware problem.  Reset
  the error condition with the UPDATE VOLUME command.  If the problem
  persists, use the DELETE VOLUME command with the DISCARD=NO option to
  remove the volume from the storage pool.

I found that to be rather unhelpful.  For one thing, I don't know what
it means by "the record tape number".  For another, no tape was marked
as being in an I/O error condition.

I have audited the tape that was mounted on drive 05A4 at the time, and
it seems to be fine.  The EXPORT NODE completed successfully many hours
later and reported that it had encountered no errors.

What's going on here?