Real Time Applications- Comp 453INSTRUCTIONS

1. This question paper has five questions2. QUESTION ONE IS COMPULSORY AND HAS 30 MARKS3. Answer any other two questions worth 20 marks

QUESTION ONE (30 marks)(a) Define real time system. What is time determinism? (2mks)(b) From point of view of requirements, how is a real-time operating system different from general purpose operating system?(3mks)(c) Explain any five design issues of real time system(5mks)(d) What is the difference between preemptive and non-preemptive scheduling? Which would be best for a real time system with computation-intensive lowpriority tasks and short deadline high priority tasks? Justify. (5mks)(e) Explain Cyclic executive algorithm for Real time Scheduling(5mks)(f) What is fault tolerance? Give two ways of classifying fault tolerant systems.(5mks)(g) Give Coffmans conditions for deadlock(5mks)

QUESTION TWO (20 marks)(a) Describe priority inversion using Mars Pathfinder example(5mks)(b) What is a digital signal? Explain steps to convert analog to digital signal(4mks)(c) Differentiate between periodic and sporadic task(2mks)(d) Discuss the use of Petri net model for real time systems(5mks)(e) Explain the task states in RTS(4mks)(f) QUESTION THREE (20 marks)(a) What is schedulability analysis? Explain how to use RMS in determining the schedulability of tasks (5mks)(b) How can one resolve the problem of priority inversion? (4mks)(c) Explain clock synchronization in distributed real time systems (2mks)(d) What is dependability in Real time systems? Explain its implication in Real time system development (5mks)(e) Differentiate between soft and hard real time giving examples in each(4mks)

QUESTION FOUR (20 marks)(a) What is an embedded system? Give at least two examples of embedded systems.(3mks)(b) What is rate monotonic scheduling? When is its use recommended?(2mks)(c) Shown below is a table of 4 periodic processes scheduled using EDF. Determine if all the deadlines will be met using utilization factor (5mks)ProcessExecution Time = CPeriod = T

P118

P225

P3410

P4 3 12(d) What is the use of a scheduler in real time system(2mks)(e) What is QoS in real time system? Discuss Diffserv and Intserv(5mks)(f) List three ways of deadlock recovery(3mks)