1 Differentiate between the following in terms of constraint

1. Differentiate between the following in terms of constraints/challenges and provide an example for each:

a. Soft real time system

b. Hard real time system

c. Embedded real time system

d. Distributed real time system

2. Differentiate between the following by providing a distinguishable definition for each:

a. Periodic task of a real time system

b. Non-periodic/Aperiodic task of a real time system

c. Sporadic task of a real time system

Solution

1)

a) Soft real time systems can miss some deadlines as compare to hard time real system , but its performance will degrade if too many deadlines are missed. An example is the sound system in our computer. If you miss a few sound bits, no big issue, but if so many are missed then a costl deal Importantly, nobody is going to die if they don\'t work correctly(not as such pace maker).

b) Hard real-time means it should hit every deadline. A less number of systems have this requirement. Some examples are nuclear systems and also medical applications such as pacemakers(it should hit every dead line), a large number of defense applications etc.

c) Real-time systems are the systems that monitor, respond , or control an external environment. This environment is connected to the computer system through sensors and other input-output interfaces. It may consist of physical objects of any form and structure.

d) Distributed real-time system consist of two challenging sets of properties that are usually imposed by the problem domain or the solution domain.Example : small microprocessors, minicomputer and large general purpose computers.

2)

a) A deadline is defined as the time interval requred for a task to be processed. For example, in a real-time scheduling algorithm has a deadline set to five nano-seconds. A task can be classified as either a periodic or aperiodic process.

b) Non-periodic/Aperiodic task of a real time system - A system is said to be unschedulable when tasks can not meet the specified deadlines.Example Sporadic Server algorithm

c) A sporadic task Ti of a real time system is represented by a three tuple: Ti = (e, g, d) where e is the worst case execution time of task, g denotes the minimum separation between two consecutive instances of the task, d is the relative deadline.