IBM F50 RS/6000 7025 - Manual (Page 138)

3. Surveillance delay
This is the length of time in minutes for the Service Processor to wait from when
the operating system is started to when the first heartbeat is expected.
Surveillance will take effect immediately after setting the parameters from the Service
Processor menus.
If operating system surveillance is enabled (and system firmware has passed control
to the operating system), and the Service Processor does not detect any heartbeats
from the operating system, the Service Processor assumes the system is hung. The
machine is left powered on and the Service Processor enters standby phase,
displaying the operating system surveillance failure code on the operator panel. If
Call-out is enabled, the Service Processor calls to report the failure.
4-30 IBM RS/6000 7025 F50 Series User's Guide