Apologies for resending this but my previous post was missing a couple of
lines from dsmserv.err.  They immediately precede the entries below:

ANR7800I DSMSERV generated at 11:19:12 on Aug 28 1998.
ANR7801I Subsystem process ID is 1146.
ANR0900I Processing options file dsmserv.opt.
ANR0990I ADSM server restart-recovery in progress.
ANR0200I Recovery log assigned capacity is 100 megabytes.
ANR0201I Database assigned capacity is 932 megabytes.
ANR0306I Recovery log volume mount in progress.
ANR0353I Recovery log analysis pass in progress.
ANR0354I Recovery log redo pass in progress.
ANR0355I Recovery log undo pass in progress.
ANR9999D logread.c(1243): Page LSN mismatch on read; expected LSN
9000.85.0, actual LSN 8994.85.0.

In light of this it may be the recovery log that's damaged. Is attempting
a recover with the mirrored volumes as simple as putting them into place
and firing it up?  I guess I am about to find out...