Total Number of Pages: 02
7th Semester Regular / Back Examination 2017-18
Real Time Systems
BRANCH: AEIE, ECE, EIE, ETC, IEE
Time: 3 Hours
Max Marks: 70
Answer Question No.1 which is compulsory and any five from the rest.
The figures in the right hand margin indicate marks.
Answer the following questions :
List the essential differences between a real-time database and a conventional
What are the various methods used to achieve hardware fault tolerance?
Differentiate between simple priority inversion and unbounded priority
What are the two main purpose of using clocks in distributed real time system?
Define byzantine clock. Explain with an example.
What are the activities performed by handler routine when a clock interrupt
What are the various real time priority levels associated with UNIX based
Differentiate between synchronous and asynchronous I/O? Which one is better
suited for use in real‐time applications?
Distinguish between execution time and response time of a task?
What is chain blocking? How is unbounded priority inversion avoided in PCP?
What is the difference between performance constraint and behavioral
constraint? Describe the various types of timing constrains with suitable
Explain the operation of priority ceiling protocol in sharing critical resources
among real time task. Explain different types of priority invesions that a task
might suffer due to lower priority task when the PCP is used to share critical
resources among a set of real task.
The following table shows the details of tasks in a real-time system. The tasks
have zero phasing and repeat with a period of 90 mSec. Determine a feasible
schedule to be used by a table-driven scheduler.
(2 x 10)
Execution time (in mSec) Deadline (in mSec) Dependency
A cyclic scheduler is used to run the following set of periodic tasks. Assume a
single processor is present in the system and all timings are given in msec.
Select the appropriate frame size. (e1 = 1, p1 = 4), (e2 = 2, p2 = 5), (e3 = 5, p3