HP Surestore 80fx Optical Drive and Library SCSI-2 Command Reference - Page 36

SCSI Command Overview SCSI Command Overview Drive Control Commands Unit Attention Condition A unit attention condition for a logical unit begins for each initiator for any of the following conditions: • Poweron or Reset • Disk Loaded • Micro Code Change • Inquiry Data Change • Mode Select Data Change The unit attention condition persists for each initiator until that initiator issues a command to the logical unit other than Request Sense or Inquiry for which the target reports a CHECK CONDITION status. If the next command from that initiator to the logical unit (following the CHECK CONDITION status) is Request Sense, the Unit Attention sense key is returned. (If any command other than Request Sense is received, the unit attention condition is lost.) If an Inquiry Command is received from an initiator with a pending unit attention condition (before the target reports CHECK CONDITION status), the target performs the Inquiry Command and does not clear the unit attention. If a Request Sense Command is received from an initiator with a pending unit attention condition (before the target reports a CHECK CONDITION status), the target discards any pending sense data, reports a Unit Attention sense key, and clears the unit attention condition for that initiator. Chapter 1 1-17