3590 customers who applied the 9430 level of microcode to their drives
thereafter encountered severely degraded performance, and indicative
error message "ANR8776W Volume ... contains lost VCR data; performance
may be degraded", most typically in HSM file retrievals, which mount
the tapes read-only.  I had our CE see if there was a later level of
microcode which fixed this problem.  Indeed, the problem was well-known
and pervasive, and the fix is in the new, December-released 9515 level.
We got a tape, and I performed the microcode update (which is simple).
Thereafter I performed the tapeutil "Space to end of data" operation as
recommended in the message description (with the tape mounted R/O), and
performed an HSM retrieval of a migrated file which had previously taken
about 20 minutes and elicited the message.  This retrieval took just over
a minute, and no error message.  If you are a 3590 customer, consider
applying this microcode.
     Richard Sims, Boston University OIT