4-3
Environmental Monitoring
In-Band Reporting
The VEM communicates with the host system using in-band reporting and sup-
ports both SAF-TE and SES protocols. The VEM card sits on the SCSI bus and
communicates directly to the host(s). The VEM card has it’s own SCSI ID (see
below) and is seen as a separate target by the host(s).
VEM SCSI ID
The VEM sits on the SCSI bus and as such it is assigned a SCSI ID. The VEM is
assigned a SCSI ID of 15 for single shelf configurations and a SCSI ID of 15 and
13 for dual shelf configurations. For more details on the SCSI ID mapping refer
to “SCSI ID Mapping” in Chapter 3.
VEM Fault Notification
The VEM has an LED mounted on it to warn of over-temperature conditions. If
an over temperature condition exists, the temperature LED (Temp) will come on,
and the alarm buzzer will sound. The alarm buzzer can be turned off by using the
Alarm Silence Button (Mute) on the VEM card.
NOTE: The alarm silence button (Mute) temporarily silences the alarm
buzzer; it does not stop the error LEDs from flashing.
In addition to the temperature LED mounted on the VEM card, the VEM also
drives fault LEDs mounted on each ACM assembly, Power Supply Carrier and
Disk Drive Carrier.
