SCSI standalone enclosure services

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SCSI standalone enclosure services is a computer protocol used mainly with disk storage enclosures. It allows a host computer to communicate with the enclosure to access its power, cooling, and other non-data characteristics.

The host computer communicates with one or more SCSI Enclosure Services (SES) controllers in the enclosure via a SCSI interface which may be Parallel SCSI, FC-AL, SAS, or SSA. Each SES controller has a SCSI identity (address) and so can accept direct SCSI commands.

Implemented commands[edit]

The following SCSI commands are implemented by standalone enclosure services devices:

SCSI command Operation code Comment
ACCESS CONTROL IN 86h Optional
ACCESS CONTROL OUT 87h Optional
CHANGE ALIASES A4h Optional
INQUIRY 12h Mandatory
LOG SELECT 4Ch Optional
LOG SENSE 4Dh Optional
MAINTENANCE IN A3h See note 1
MAINTENANCE OUT A4h See note 1
MODE SELECT 15h/55h Optional
MODE SENSE 1Ah/5Ah Optional
PERSISTENT RESERVE IN 5Eh Optional
PERSISTENT RESERVE OUT 5Fh Optional
READ BUFFER 3Ch Optional
RECEIVE DIAGNOSTIC RESULTS 1Ch Mandatory
REDUNDANCY GROUP IN BAh See note 1
REDUNDANCY GROUP OUT BBh See note 1
REPORT ALIASES A3h Optional
REPORT DEVICE IDENTIFIER A3h Optional
REPORT LUNS A0h Mandatory
REPORT PRIORITY A3h Optional
REPORT SUPPORTED OPERATION CODES A3h Optional
REPORT SUPPORTED TASK MANAGEMENT FUNCTIONS A3h Optional
REPORT TARGET PORT GROUPS A3h Optional
REPORT TIMESTAMP A3h Optional
REQUEST SENSE 03h Mandatory
SEND DIAGNOSTIC 1Dh Mandatory
SET DEVICE IDENTIFIER A4h Optional
SET PRIORITY A4h Optional
SET TARGET PORT GROUPS A4h Optional
SET TIMESTAMP A4h Optional
SPARE IN BCh See note 1
SPARE OUT BDh See note 1
TEST UNIT READY 00h Mandatory
VOLUME SET IN BEh See note 1
VOLUME SET OUT BFh See note 1
WRITE BUFFER 3Bh Optional

Note 1: The initiator needs to send a SCSI inquiry to interrogate the SCCS bit which says whether the SES controller has this command.