rdisp/vm_alarm_time is a SAP Parameter attribute which is used to control alarm timer for vm container information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
The frequency of the alarm time can be defined for the VM Container with
this parameter. This is needed, for example, for Java debugging, in
order to deactivate a running application temporarily.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.