HP LTO 4 SAS, LTO 4 FC manual ACI command set, ACI commands that affect drive streaming performance

cartridge at the moment that the drive starts to pull it into the drive, if it is configured for that type of operation.

This degree of control over synchronization cannot be achieved though the host’s backup software; it must be controlled directly by the library controller. Most tape libraries work this way today. The process is transparent to the backup software.

SCSI pass-through mode

The ACI protocol allows the transfer of “packetized” SCSI commands from an attached controller and submit them to the tape drive as if they have been received on the drive’s own SCSI bus. This enables the attached controller to access and control the drive in exactly the same way as it would via the SCSI bus.

ACI command set

The following ACI commands are supported on HP Ultrium drives:

	Mandatory Commands
00h	Get Drive Info
01h	Load
02h	Unload
03h	Get Drive Status
04h	Set Drive Configuration
05h	Get Drive Configuration
06h	Reset
07h	Set Baud Rate
08h	No Op
09h	Get Error Info
0Ah	Acknowledge Attention

	Optional Commands
40h	Send SCSI Command
42h	Send Firmware Image
43h	Get Firmware Segment
49h	Get Buffer Size
4Ah	Send Firmware Segment
4Bh	Set Time
4Ch	Get Time

ACI commands that affect drive streaming performance

Commands that alter the state of the drive in some way will affect the performance of the drive when stream reading or writing. It is recommended that no command within the following set are sent to the drive while the drive is writing or reading as it would affect the data throughput to or from the drive:

•Load

•Unload

•Send Firmware Image

•Send Firmware Segment

•Reset

•Set Drive Configuration—if the host (SCSI or FC) is reconfigured

38 Supporting Ultrium features

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