IBM T200F User Manual download pdf (Page 107)

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:

v Power-on procedure

v Reset strategy

v Abort handling

v Multi-initiator support

v Status 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:

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

v Any queued I/O processes from other initiators are removed.

v All reservations are cleared.

v All mode values are reset to their defaults.

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

v A unit attention condition is set.

v A 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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IBM T200F User Manual Page 107