Real Time Systems - Unit Wise Questions

1. Define deferrable server.Describe the operation of deferrable server in detail with example.

1. What is real system? Explain its various components with a suitable block diagram.

1. List the advantages and disadvantage of priority based scheduling. State the validation problem for  priority based system and explain with example.

1. What do you understand by Basic Priority inheritance protocol? Explain it with the help of suitable example.

2. Differentiate between fixed priority and dynamic priority algorithms.

2. What are three commonly used approaches in scheduling the real time systems? Compare and contrast each of them.

1. Explain the various components of a real time system with suitable block diagram. State and prove the optimal Earliest-Deadline-First(EDF) algorithm.

1. How real time task are scheduled using Latest Release Time (LRT) algorithms? Explain non-optimality of EDF and LST algorithms.

1. What do you understand by basic priority ceiling protocol? Explain it with the help of suitable example.

1. Describe  how is the polling, priority scheduling and schedulability analysis performed for prioritized access in IEEE 802.5 Token Rings. What are the other factors those should be taken into account?

1. Describe the rules for basic priority inheritance protocol with example.

1. What is real time system? Explain its various components with a suitable block diagram. Explain the RADAR signals processing with block diagram.

2. What do you understand by digital control? Prove that Earliest Deadline First (EDF) algorithm is not optimal for scheduling preemptable jobs on more than one processor.

2. Differentiate between rate-monotonic and deadline monotonic algorithms with example.

2. Explain the multiprocessor priority ceiling protocol with suitable example.

3. Differentiate between rate-monotonic and deadline monotonic algorithms with example.

2. Differentiate between fixed priority and dynamic priority algorithms. State and prove the optimality of Least Slack Time(LST) First algorithm.

2. Compare and contrast between fixed and dynamic priority system."The implementation of slack stealing server for fixed priority system is difficult." Is it true? Explain.

3. A system contains nine non preemptable jobs named J_i, for i = 1,2,...9. The execution times are 4, 3, 3, 3, 5, 5, 5, 5, and 10, respectively, their release times are equal to 0, and their deadlines are 10.J1 is the immediate predecessor of J₉, and J₄ is the immediate predecessor of J₅, J₆, J₇, and J₈. There are no other precedence constraints. For all the jobs, J₁ has a higher priority than J_k if i < k.

a) Draw the precedence graph of the jobs.

b) Can the jobs meet their deadlines if they are scheduled  on three processors?

c) Can the jobs meet their dead lines if made preemptable and schedule them preemptively.

2. Define priority driven algorithms. State and prove the optimal earliest deadline first (EDF) theorem.

2. What is slack stealer server? How it is different from polling server? Show that slack stealer improves the response time of a periodic jobs in deadline driven system.

2. What do you mean by static computation in fixed-priority systems? Explain with example.

2. Define resource reservation protocol. Explain in brief, the different types of issues that a resource reservation protocol must deal with.

3. List the properties of basic priority inheritance protocol. "The priority ceiling protocol avoids both priority inversion and deadlock in resource allocation." Justify it with suitable example.

3. What are the three commonly used approaches to scheduling the real time systems? Compare each of them.

3. Explain  the Stack Stealing in deadline-driven system with suitable example.

3. What is multi processor priority ceiling protocol? Describe it with the help of suitable diagrams.

3. Explain the Greedy Weighted Round Robin(WWR) disciplines and time. Driven Weighted Round (WWR) disciplines with example.

3. What do you understand by slack stealing in a deadline driven system? Explain the operation of a slack stealer with example.

3. Define rate-monotonic (RM) and deadline-monotonic (DM) algorithms. Describe the DM algorithm with example.

3. Define deferrable server. Describe the operation of deferrable servers in detail with example.

3. What is mutual exclusion and critical section? List and explain the effects of resource allocation in real time scheduling with example.

4. Differentiate between dynamic and static real time systems.

4. Differentiate between fixed priority and dynamic priority algorithms.

4. Explain how real-time commands are handled in Air Traffic Control (ATC) System.

4. What do you understand by "Tracking" and "Gating" in a Radar system? Explain.

5. What is the use of priority ceiling protocol?

5. Briefly explain clock driven scheduling. List its pros and cons.

4. Differentiate between dynamic and static real time systems.

4. Define wormhole network. Describe routing and transmission mechanism in a wormhole network.

4. What is digital control? Explain with example.

4. Explain the real-time command and control system with suitable example.

4. Explain the Kalman filter with example.

4. What is the difference between real time system and embedded system? Explain the sample data system with necessary block diagram.

4. Define schedule and scheduler. List out the conditions under which a schedule becomes a "valid  schedule".

5. Draw and describe a model of real time system.

5. Describe the term tracking and gating used in a radar signal processing system.

6. Explain the different issues that needs to be dealt by a resource reservation protocol within a multicast environment.

6. Highlight on internet and resource reservation protocols.

5. Explain the digital controller with example.

6. Differentiate between offline and online scheduling in a real time system.

6. What are the advantages and disadvantages of clock driven scheduling approach?

6. Define release time jitter, relative deadline, and hyper period. If the execution times of three periodic tasks are 1, 1 and 3, and their periods are 3, 4, and 10, then find out the total number of jobs in the hyper-period, and total utilization of jobs.

6. Compare and Contrast between Sporadic and Aperiodic job. At what condition the scheduling algorithms becomes optimal? Explain.

6. Explain the diagram of radar signal processing and tracking system.

7. Where and how can we use off-line scheduling and on-line scheduling ? Explain with an example.

7. Highlight on resource parameters of jobs. Why is it critical?

6. Differentiate between dynamic system and static systems with example.

6. Differentiate between data dependency and temporal dependency.

6. What is the major difference between precedence and task graph? Explain about the functional parameter of real-time jobs.

7. List out the advantages and disadvantages of a clock driven approach to scheduling.

7. Define temporal parameter of real time workload? Explain different types of temporal parameters of a job.

7. Describe the operation of total bandwidth server in brief.

7. Describe the significance of laxity type with the help of suitable diagram. 

7. How sporadic jobs are scheduled in EDF scheduling? Explain with example.

7. Explain the sporadic server in fixed priority system.

7. State and prove the Optimal Least-Stack-time-first (LST) algorithm.

8. Highlight on the requirements of Real-time Multimedia Traffic.

7. Differentiate between clock-driven scheduling and priority-driven scheduling.

8. What are the challenges in validating timing constraints in priority-driven systems? Explain.

7. How frame overruns are handled in cyclic Scheduling? Calculate the possible valid frame size for system with tasks T1(2, 1, 3),T2(4 , 1, 6), T3(6, 2, 8) and T4(6, 2, 8).

9. Compare and contrast on slack stealing in fixed-priority systems and in deadline-driven systems respectively.

8. Differentiate between online and off-line scheduling.

8. Explain the slack computation in fixed priority system with example.

8. Explain the meaning of "priority-invention" with the help of timing diagram.

8. Explain the schedulability of sporadic jobs in deadline-driven systems.

9. Explain Priority-Inversion with the help of timing diagram.

8. Define the clock-driven scheduling. What are the advantages and disadvantages of it?

8. State the optimality conditions for fixed priority algorithms. Consider a system with real time tasks T1(4, 1, 6) T2(10, 2, 20)  T3(20, 1. 30), T4(10, 5, 8) and T5(8, 1) are scheduled by using EDF algorithms. Find it feasible to schedule or not.

8. What are the requirements for Real-Time Multimedia Traffic? Explain. 

8. List the assumptions made for priority driven scheduling. Construct the LST schedule for a system with tasks T1(2,0.5), T2(3,1) and T3(6,2).

8. Differentiate between dynamic systems and static system in real time systems.

9. What do you understand Greedy Weighted Round Robin scheduling in a packet switched network? Explain it in detail.

9. State the optimality conditions for dynamic priority algorithms. Consider a system with real-time T1(4,1,6), T2(10,2,20), T3(20,1,30), T4(10,0,5.8) and T5(8,1)are scheduled by using RM or DM algorithms. Find is it feasible to schedule or not.

9. Differentiate between fixed-priority algorithm and dynamic-priority algorithm.

9. Differentiate between periodic and bandwidth preserving server. Explain deferrable server with example.

9. Why does the scheduler perform an acceptance test while scheduling sporadic jobs? Explain.

10. How can concurrent access to data objects be controlled and why is it required?

9. Explain  with diagram of real time communication model.

9. What are the procedures of a simple acceptance test in deadline-driven systems? Explain.

10.What do you mean by scheduling hierarchy? Explain.

9. Differentiate between priority inheritance and priority ceiling protocols.

9. What do you understand by 'Busy Intervals' in fixed priority tasks with arbitrary response times? Explain.

10. What are the properties of the priority-inheritance protocol? Explain.

10. Define busy interval. Calculate the busy interval for task T1(2,1), T2(3,1,25) and T3(5, 0.25) over the interval (0, 12) schedule through the Rate Monotonic (RM) algorithms.

10. Prove that the longest blocking time suffered by every job is the same for the sack based and basic priority ceiling protocols?

10. What are the different types of issues that a resource reservation protocol must deal with in a multicast environment? Explain. 

11. Explain medium-access protocols of broascast networks.

10. Define Deferrable server.State and explain the consumption and replenishment rules of deferrable servers. 

11. Example digital control with example.

10. Explain the sporadic server in fixed-priority systems with example.

10. What is constant utilization server algorithm ? Explain.

10. Describe a simple bin parking formulation method of task assignment in a multiprocessor system.

11. How is the connection established in a Greedy  WRR scheduling algorithms ? Explain.

11. Define task assignment in end to end task model. State and explain the task assignment in multiprocessor system using simple bin packing algorithms with example.

12. How precedence constraints and data dependency effect the execution time of RTS ? 

11. What is RCTP control protocol? Explain with example.

11. What is rate monotonic algorithm? Explain with suitable example.

11. Explain the weighted round robin service disciplines with example.

10. Define critical instant. Calculate the critical instant for real-time tasks: T1(2,0,6), T2(2,5,0.5), T3(3,1.2) schedule through the Deadline Monotonic (DM) algorithms over the interval(0, 12).

12. Explain clock driven approach. What are its disadvantages?

11. What do you understand by Task Assignment, Job Shops and Flow Shops? Explain.

11. Describe the meaning of resource conflict, blocking, priority inversion, and deadlock caused by resource contention.

11. Explain 'Priority Inversion' caused by resource contention, with suitable example.

12. Why real time data cannot use TCP protocol? Give reasons.

12. Explain the real time communication model with diagram.

12. Describe a real time communication architecture of distributed system with diagram.

12. Write down the total bandwidth server algorithm and explain it.

12. Describe a real-time communication model with the help of suitable diagram.

12. Explain the priority based service disciplines for switched networks.

11. Explain about Multiprocessor Ceiling Protocol (MPCP) for resource allocation in a multiprocessor system with example.

12. Define real time traffic model.List and explain the different types of services discipline used in real time communication.

12. Describe the meaning of job shops and flow shops of end to end tasks in a multiprocessor scheduling.

13. Write short notes (any two)

a. Priority inheritance

b. Critical instants

c. Soft real time system

13. Write Short notes.(any two)

a. Kalman filter

b. Deadbeat control

c. Sporadic jobs

13. Write short note on:

a. Scheduling hierarchy 

b. Communication in multicomputer system.

13. Write short notes on:(Any Two)

a. Service discipline in real time communication

b. Critical section and outermost critical section

c. Context switches

13. Write short notes on:

a. Embedded System

b. Real Time Control Protocol(RTCP)

13. Write short note on:

a. Real time protocol

b. IEEE 802 token ring

12. Define the terms throughput, Delay and jitter. How medium access protocol used in control area network(CAN)? Explain.

13. Write short notes on:

a. Fixed Priority Scheduling in CAN

b. Greedy WRR discipline

13. Write short notes on:

a) Identical versus heterogeneous processors

b) Real Time Protocol(RTP)

13. Write short notes on(any two):

a) Data dependency and functional parameter of job.

b) Resource Reservation Protocol

c) Pros and corns of cyclic scheduler

13. Write short notes on(any two):

a) Inter-Processor Communication(IPC)

b) Weighted Fair Queuing Server

c) Offline Vs. Online Scheduling

1. Explain the hard real time system and soft real time system  with example. 

5. What is soft real time systems? Explain with example.

5. What is hard real time system? Explain with example.

5. Why validation of hard timing constraint is required? Explain the characteristics of soft real time system.

5.  What are the meanings of hard real time system, hard timing constraints and temporal quality of  service guarantees?

5. What is timing constraints? Explain the characteristics of Hard Real-Time system with example.

5. What do you understand  by timing constraints and tardiness? Why does a hard real time system require time guarantees?

6. Differentiate between hard real time systems and soft real time systems. Give three examples of each.