System Uptime can be monitored through either cdm, net_connect, ntperf, or snmpget.
cdm
Computer uptime, as reported by the cdm probe will be shown as cumulative, in minutes, since the robot was started.
If you are looking for availability you might try using the net_connect probe to ping a device and then base your SLA on the maximum response time you consider the node to be 'available' versus unavailable.
Uptime is the number of seconds the computer has been running since reboot. It is not that useful for an SLA because it is a counter that continues to rise until a reboot occurs.
net_connect (most common approach)
You can use net_connect to ping the node every x minutes. Then use SLA/SLO engine to set a good value for each sample - like zero or greater - which shows that the computer was responding. If the computer does not respond, the net_connect probe will send a NULL which will be counted as a 'fail' by the SLA engine. The SLA engine then calculates the number of good samples vs the number of failures and provides a percentage of the SLA period in which the computer was 'up.'
ntperf
Windows performance counter: \System\System Up Time
In Windows, System Up Time is the elapsed time (in seconds) that the computer has been running since it was last started.? This counter displays the difference between the start time and the current time.
snmpget
You can do a web search for the uptime OID and use the MIB browser and browse for it and add it to your snmpget configuration.
MIB variable: sysUpTime
OID: .1.3.6.1.2.1.1.3.0
Create a new QoS definition for uptime and use the collected value as desired.
Displaying Uptime
Use a dashboard view or a List View depending on your needs.
In OC the uptime stats from cdm (QOS_COMPUTER_UPTIME) when collected, would be displayed under the given node->Metrics Tab->System->Host