REAL TIME SYSTEMS:
A Real-Time system is used when there are rigid time requirements on the operation of a processor or the flow of data and is often used as a control device in a dedicated application.
1. A real time OS has well defined, fixed time constraints.
2. Processing must be done with in the defined constraints or the system will fail.
There are 2 flavours of Real-Time systems.
1. Hard Real-Time system.
2. Soft Real-Time system.
A Hard Real-Time system gurantees that critical tasks complete on time. This goal requires that all delays in the system be bounded, from the retrieval of stored data to the time that is takes it takes the facilities that are available in Hard Real-Time systems.
A less restrictive type of Real-Time system, where a critical Real-Time system task gets priority over other tasks... that priority untill if completes. As in hard Real-Time systems, kernel delays need to be bounded. A Real-Time task cannot be kept waiting identifitely for the kernal to run it.