Scheduling Requirements

Definition

A scheduling requirement is a performance requirement that specifies the mandatory schedule of the behavior of an application or component.

Objectives

The typical objectives of a scheduling requirement are to ensure that:

• The application or component conforms to a required schedule.
• Specific behaviors happen:
  • At specified times.
  • Within a specified time interval of a specified time (i.e., jitter).

Examples

The following are typical examples of scheduling requirements:

• “The monthly status report shall be produced between 11PM and 12PM the first business day of each month.”
• “The application shall periodically read the temperature sensors every three seconds.”
• “When in flight, if the avionics application cannot completely process the aileron position sensor readings within 30 miliseconds, then it shall abandon the incompletely processed readings and start over by taking and processing new readings.”

Guidelines

The following guidelines have been found to be useful when producing scheduling requirements:

• Document all required behaviors that happen at or by specific times.
• If a time interval exists during which a behavior may occur (i.e., jitter), then specify that time interval.