Seagate Ultra 320, Ultra 160 manual Incorrect initiator connection

Since new operating definitions may preclude the execution of tasks that are already in progress, the target may disconnect to allow completion of any tasks that are in progress. Operating definition changes that may cause conflicts with the normal operation from other initiators shall be indicated to those initiators by generating a Unit Attention condition for each other initiator. The additional sense code shall be set to Changed Operating Definition.

A SCSI initiator port may request a list of the operating definitions that the target supports and descriptive text for each operating definition using the INQUIRY command.

7.10Incorrect initiator connection

An incorrect initiator connection occurs on a reconnection if:

a.a SCSI initiator port attempts to reconnect to a task, and

b.a soft reset condition has not occurred, and

c.the initiator does not send an Abort, Abort Tag, Bus Device Reset, Clear Task Set, Continue Task, or Ter- minate Task message during the same MESSAGE OUT phase as the IDENTIFY message.

An incorrect initiator connection also occurs on an initial connection when a SCSI initiator port:

a.attempts to establish an I T L Q nexus when an I T L nexus already exists from a previous connection, or

b.attempts to establish an I T L nexus when an I T L Q nexus already exists unless there is a contingent allegiance or extended contingent allegiance condition present for the logical unit or target routine.

A SCSI target port that detects an incorrect initiator connection shall abort all tasks for the initiator on the logi- cal unit or target routine and shall return CHECK CONDITION status. The sense key shall be set to Aborted Command and the additional sense code shall be set to Overlapped Commands Attempted.

An incorrect initiator connection may be indicative of a serious error and if not detected could result in a task operating with a wrong set of pointers. This is considered a catastrophic failure on the part of the initiator. Therefore, host-specific error recovery procedures may be required to guarantee the data integrity on the medium. The target may return additional sense data to aid in this error recovery procedure. Also, some tar- gets may not detect an incorrect initiator connection until after the command descriptor block has been received.

150 Parallel SCSI Interface Product Manual, Rev. A