Learn in the textbookApplying Virtualization and System Usage/Operation Modes
DefinitionReal-time processing (リアルタイム処理) is a processing mode that handles a request or data as soon as it arises and returns the result within a set time.
ExplanationIt is used where a late result causes trouble, such as train seat reservations or controlling factory machines. What it requires is less raw speed than the ability to respond by the set deadline.
AnalogyIt is like a fire station taking an emergency call. It acts the moment the call comes in and is expected to meet its target arrival time.
Memory hookReal time means time in the real world: processing keeps pace with events as they actually happen.