SCSI element codes

SCSI Enclosure Services (SES) devices contains a number of elements, each of which is defined by a one byte SCSI element code. There are many different element codes defined to cover various devices as shown in the list below.

List of SES element codes[edit]

00h - unspecified
01h - device - disk-drive or other SCSI device
02h - power-supply
03h - cooling
04h - temperature-sensor
05h - door lock
06h - audible alarm
07h - enclosure services controller electronics
08h - SCC controller electronics
09h - nonvolatile cache
0Ah - invalid operation reason - used to determine why an ESI device has failed to complete a command
0Bh - UPS
0Ch - display
0Dh - keypad
0Eh - enclosure
0Fh - SCSI port/transceiver
10h - language
11h - communication port
12h - voltage sensor
13h - current sensor
14h - SCSI target port
15h - SCSI initiator port
16h - simple subenclosure
17h - array device
18h - SAS expander
19h - SAS connector
1Ah-7Fh - reserved
80h-FFh - vendor-specific

How SES elements are used[edit]

The SCSI initiator communicates with an SES device using two SCSI commands, Send Diagnostic and Receive Diagnostic Results. The most common SES elements are power-supply, cooling-fan, temperature-sensor and UPS. The SCSI command protocols assume that there may be more than one of each device type so they must each be given an 8-bit address. When the SES controller is interrogated for the status of an SES element, the response includes a 4-bit status code. The most common element status codes are: 1h=OK, 2h=critical, 3h=warning, 5h=not installed.

See the SES article for a more detailed description.

Status codes[edit]

When a SCSI SES controller is interrogated for the status of a SES element, the response includes a 4-bit SCSI element status code. The list of valid codes is:

0h - unsupported - status detection is not implemented for this element
1h - OK - element is installed and no error conditions are known
2h - critical - critical condition is detected
3h - noncritical (warning) - noncritical condition is detected
4h - unrecoverable - unrecoverable condition is detected
5h - not installed - this element is not installed in the enclosure
6h - unknown - sensor has failed or element status is not available
7h - not available - element installed, no known errors, but the element has not been set into operation
8h-Fh - reserved

References[edit]

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