ISRO2017-73

Question

Which of the following statement is true?

• A. Hard real time OS has less jitter than soft real time OS
• B. Hard real time OS has more jitter than soft real time OS
• C. Hard real time OS has equal jitter as soft real time OS
• D. None of the above

Comments

Jitter means timing error in task ,hard real time operating system can not tolerate any timing error but soft real time system can tolerate some timing error

Answer 1

1. SOFT REAL TIME OPERATING SYSTEM

Soft real time OS is a type of OS where certain deadlines may be missed, they will respond at a time t=0+.

Soft real time systems are not constrained to extreme rules. The critical time of the soft real time may be delayed to some extent. The expected latency between the tasks and time constraints may be deviated.

The preemption period for a soft real time task is about few milliseconds.

EXAMPLES

Digital camera, mobile phones, online data base etc.

1. HARD REAL TIME OPERATING SYSTEM

Hard real time OS is a type of OS we can predict the deadline, they will respond at a time t=0. Hard real time systems are constrained to predicted time constraints, deadlines and latency.

EXAMPLES:

Air bag control in cars, anti-lock brake, engine control system etc.

The preemption period for hard real time system is almost less than few microseconds.

Jitter MEANS timing error in task, hence A hard real-time operating system has less jitter than a soft real-time operating system.

Answer 2

A hard real-time operating system has less jitter than a soft real-time operating system.

Reference:https://en.wikipedia.org/wiki/Real-time_operating_system