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SES(4) Device Drivers Manual SES(4)

sesSCSI Enclosure Services

ses* at scsibus?

The ses driver provides support for monitoring the various environmental sensors present in SCSI enclosures using the SCSI Enclosure Services command set. The hardware monitoring is accessed via the hw.sensors sysctl(8) variable.

SCSI devices have a fairly high level interface to the system and talk to it via a SCSI host adapter (e.g. ahc(4)). A SCSI adapter must also be separately configured into the system before a SCSI enclosure can be configured.

When the SCSI adapter is probed during boot, the SCSI bus is scanned for devices. Any SCSI-2 devices of type “Enclosure service” or SCSI-3 devices of type “Processor” will be attached to the ses driver.

SES compliant devices can provide an arbitrary set of sensors which may include the following types:

uK temperature
RPM fan
On/Off power supply
On/Off door lock
On/Off enclosure alarm

Sensor data is updated every 10 seconds.

An enclosure may provide environmental information using an alternative command set to the SCSI Enclosure Services used by this driver. Enclosures using the SCSI Accessed Fault-Tolerant Enclosure command set may be monitored by the safte(4) driver.

intro(4), safte(4), scsibus(4), sensorsd(8), sysctl(8)

The ses driver first appeared in OpenBSD 3.8.

The ses driver was written by David Gwynne <>.

July 16, 2013 OpenBSD-6.4