It's fixed. Indeed, Tru64 V5.1B patch kit 3 does break Netbackup, and
probably other things. The patch:

* Patch C 00407.01 - AT_G08565: Fix for premature connection termination

available from HP, fixes the problem.

Thanks for the hints and suggestions.

                                                - Bluejay Adametz

I know you believe you understand what you think I said, but I'm not
sure you realize that what I think you think I said was not what I meant.

> I just upgraded a cluster of two Tru64 DS25s from patch kit 2 
> to patch kit 3
> of V5.1B. 
> 
> A member in this cluster runs Netbackup Datacenter V3.4.1 to 
> back up itself
> to an SDLT library on a SAN. It was working fine before I 
> installed patch
> kit 3, but now when I attempt to back it up, a tape loads, 
> and then the
> backup fails with:
> 
> 12:42:47 from client mynode: ERR - Only wrote 57344 of 262144 bytes to
> STDOUT.
>          Errno = 22: Invalid argument
> 12:42:47 media manager terminated during mount of media id 
> BWL812, possible
>          media mount timeout
>