IBM T200F manual Attachment Features, Types of Interface Attachments, Common Tape LUN Behaviors

Chapter 5. Attachment Features

Types of Interface Attachments

The Ultrium Tape Drive communicates with servers that use SCSI parallel or Fibre Channel interfaces. The interfaces share certain tape LUN behaviors, but also possess unique features. This chapter describes the common and unique features of both types of interfaces.

Common Tape LUN Behaviors

SCSI parallel and Fibre Channel interfaces share the following tape LUN behaviors:

vPower-on procedure

vReset strategy

vAbort handling

vMulti-initiator support

vStatus codes

The sections that follow describe each behavior.

Power-On

The drive responds to INQUIRY, REPORT LUNs, REQUEST SENSE, and TEST UNIT READY commands within 5 seconds of power-on. The first command (other than INQUIRY or REQUEST SENSE) from any initiator gets a Check Condition status with Unit Attention sense data for the power-on. After this, any medium access command is reported with a Sense Key of Not Ready and an ASC/ASCQ of LUN Has Not Self-Configured Yet (3E00). Once the drive has completed its self test and setup procedures, the drive attempts to load any tape that is present. Medium access commands are reported with an ASC/ASCQ of Drive in Process of Becoming Ready (0401).

Reset Strategy

The drive supports the hard reset option as is required by SCSI-3. On receiving a reset, the following actions are taken:

vThe current I/O process is aborted, as in “Abort Handling” on page 94.

vAny queued I/O processes from other initiators are removed.

vAll reservations are cleared.

vAll mode values are reset to their defaults.

vSynchronous/Wide negotiations are cleared (applies only to SCSI parallel attach).

vA unit attention condition is set.

vA logical position is established that may or may not be the same as the position prior to the reset. Where possible, the logical position prior to reset is maintained.

For drives that use a Fibre Channel interface, the next command that is eligible for the Unit Attention Check Condition from each initiator gets a Check Condition status, with Unit Attention sense data for the reset. However, other commands may not be processed until the internal state of the drive has been reset.

Drives that use a SCSI interface are able to respond to the INQUIRY, REPORT LUNs, REQUEST SENSE, and TEST UNIT READY commands within 250 ms of the reset line being released. The next command that is eligible for the Unit

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