HP HPE StoreEver LTO-8 Ultrium Tape Technical Reference Manual page 22

LED Sequence
Ready is ON.
Ready FLASHES.
22 Operating and using the Ultrium 8 tape drive
Cause
The drive is ready for
operation.
The drive is carrying out a
normal activity (read,
write).
Action required
None. This is normal.
None.
If the drive is upgrading firmware, do not reset or
power cycle it.
Table Continued