Running stenc --detail shows Volume Encryption = Unable to determine?

[c3rberus]

Recently got a new tape library, using stenc 1.0.7 on AIX to enable tape encryption.

stenc -f /dev/rmt0 -e on -k /etc/tape/tape.key -a 1
Provided key length is 256 bits.
Key checksum is cc99.
Turning on encryption on device '/dev/rmt0.1'...
Success! See '/var/log/stenc' for a key change audit log.

stenc -f /dev/rmt0 --detail
Status for /dev/rmt0.1
--------------------------------------------------
Device Mfg:              IBM
Product ID:              ULT3580-HH8
Product Revision:        N4Q1
Drive Encryption:        on
Drive Output:            Decrypting
                         Unencrypted data not outputted
Drive Input:             Encrypting
Key Instance Counter:    3
Encryption Algorithm:    1
Drive Key Desc.(uKAD):   tape_key
Volume Encryption:       Unable to determine
Volume Algorithm:        1

Drive encryption shows on, however volume encryption returns "Unable to determine", I am a bit concerned.

Is it safe to write/read encrypted tapes with this sort of status?

[jmwilson]

It appears a likely cause of this is that the tape is positioned at a file mark where the current block doesn't contain any data.