HP LTO 4 FC Recommended Get Drive Status polling frequency, ACI protocol communications retry

HP recommends configuration of the upgrade protect features to enabled. (the Upgrade Protect bit of the Set Drive Configuration command is set to 1). This will ensure that if a firmware upgrade cartridge is loaded inadvertently, the drive’s micro-code will not be upgraded unnecessarily.

If requested, HP will alter the default settings for Auto-Eject, Auto-Load, Auto-Thread, Clean Protect, and Upgrade Protect features in your particular variant of the firmware.

Recommended Get Drive Status polling frequency

HP recommends that the polling frequency of a Get Drive Status command should be in the range 2–5s, particularly during cartridge loading and unloading. This frequency should be sufficient to capture state changes in the drive while not adding significant processing overhead to the drive or automation controller.

ACI protocol communications retry

The ACI protocol specifies a comprehensive packet retry mechanism. Under certain timing conditions, especially for automation controllers that use a single microprocessor and multiplex the ACI communications from one tape drive to another, the automation controller can receive a response packet from the tape drive that it does not need. When this situation arises, the automation controller should send a positive acknowledgement control character, <ACK>, to the tape drive and discard the packet. Since the tape drive receives the <ACK>, it will not re-send the packet.

Upgrading the drive firmware

There are three methods of updating the firmware in the tape drive:

Firmware upgrade via tape

It is expected that firmware upgrades via tape will be done under the control of the library controller and the Operator Control Panel and independently of the host interface.

If the Upgrade Protect bit is set to 1 in the Set Drive Configuration command (which is recommended), the tape can be loaded into the drive in the usual manner, except that the ACI Load command must be sent to the drive and the Upgrade bit and Thread bit in byte 1 of the Load command must be set to 1.

If the Immediate Response bit in the ACI Load command is not set to 1 and the firmware upgrade failed (say due to an invalid image on the tape), the ACI Load command will report a CHECK CONDITION with appropriate sense key and additional sense.

If the Immediate Response bit is set to 1 and the firmware upgrade fails, the automation controller can detect the failure by noting that the Tape Activity field in the Get Drive Status response returns to Idle and the tape drive does not enter its ACI initialization procedure.

•While the drive is preparing to upgrade the firmware, it will report Tape Activity = “Code Update in Progress”.

•While it is actually upgrading the firmware, the drive will not respond to ACI commands.

•After the firmware upgrade has completed the drive will reset and send out an ENQ byte over ACI.

After performing a firmware upgrade via tape it is recommended that the library controller checks that an ENQ byte is sent by the drive after it power-cycles at the end of the firmware upgrade

HP LTO Ultrium 4 drives technical reference manual, volume 2: software integration 45 HP restricted