Questions for the test

Questions for the test
1. What do you understand by the term "real time"? How does the concept of real time differ from the traditional concept of time? Explain your answer with a suitable example.
2. What does the term "real" mean in a real-time system? Explain what you mean by real time system.
3. Using a block diagram, show the important hardware components of a real-time system and their interaction. Explain the roles of the various components.
4. Why is it necessary to pre-process raw sensor signals before they can be used by a computer?
5. Identify the key differences between hard real-time systems, soft real-time systems, and hard real-time systems.
6. Explain the key differences between the characteristics of a soft real-time task such as web browsing and a non-real-time task such as email delivery.
7. Give an example of a soft real-time task and a non-real-time task. Explain the key difference between the characteristics of these two task types.
8. Draw a schematic model showing the important components of a typical hard real-time system. Explain the operation of the output interface using a suitable circuit diagram.
9. Draw a schematic model showing the important components of a typical hard real-time system. Explain the operation of the input interface using a suitable circuit diagram.
10. In a hard real-time system, is it necessary for every task in the system to be hard real-time? Explain your answer with a suitable example.
11. Explain why hardware fault tolerance is easier to achieve than software fault tolerance.
12. What are the main methods available to achieve software fault tolerance? What are the disadvantages of these methods?
13. Briefly explain how hardware failures (such as processor failures) can be tolerated in security-critical hard real-time applications.
14. Explain why security and reliability are not independent issues in security-critical hard real-time systems.
15. What is a safety critical system? Give some practical examples of security-critical hard real-time systems.
16. What types of time constraints can occur in the system. Give examples of each.
17. What do you understand by the scheduling point in the task scheduling algorithm? How are scheduling points determined in (i) clock, (ii) event, (iii) hybrid schedulers?
18. Real-time tasks are usually classified into periodic, aperiodic and sporadic real-time tasks. What are the main criteria by which a real-time task can be defined as belonging to one of the three categories?
19. Real-time tasks are usually classified into periodic, aperiodic and sporadic real-time tasks. Identify some characteristics unique to each of the three task categories.
20. What do you understand by the optimal scheduling algorithm? Is it true that the time complexity of an optimal scheduling algorithm for scheduling a set of tasks in real time in a single processor is too expensive to be of any practical use?
21. What do you understand by jitter associated with a periodic task? What caused this trembling? How to overcome them?
22. What is EDF? Briefly describe the principle of operation of this algorithm.
23. What is an RMA? Briefly describe the principle of operation of this algorithm.
24. List the main characteristics of real-time systems. Give them a brief description.
25. What is task criticality? How and by what is it measured?
26. What does it mean that "Real-time systems are often reactive"?
27. Explain why in RTS security and reliability should be considered as interrelated characteristics. Give examples of an insecure but reliable system and a secure but unreliable system.
28. What is a safety critical system? Give examples of a safety-critical system and a non-safety-critical system.
29. How to achieve high reliability? What are the ways to improve system reliability?
30. What methods of software fault tolerance do you know? Give them a brief description.
31. What types of real-time tasks do you know? Give them a brief description. Give examples.
32. What is Timing Constraints? What needs to be considered before the temporal behavior of real time systems is understood?
33. Briefly describe the Classification of Timing Constraints.
34. How many types of deadline restrictions do you know? Briefly describe them.
35. What is the modeling of time constraints based on? Justify your answer with examples.
36. What is the difference between a performance constraint and a behavior constraint in a real-time system? Give practical examples of each type of restriction.
37. What are the constraints that a set of periodic real-time tasks must satisfy in order for RMA to be the optimal scheduler for a set of tasks?
38. Real-time tasks are generally classified into periodic, aperiodic and sporadic real-time tasks. What are the main criteria by which a real-time task can be defined as belonging to one of the three categories?
39. Real-time tasks are usually classified into periodic, aperiodic and sporadic real-time tasks. Identify some characteristics unique to each of the three task categories.
40. Real-time tasks are generally classified into periodic, aperiodic and sporadic real-time tasks. Give examples of tasks in practical systems that fall into each of the three categories.
41. What do you understand by the optimal planning algorithm? Is it true that the time complexity of an optimal scheduling algorithm for scheduling a set of tasks in real time in a single processor is too expensive to be of any practical use? Explain your answer.
42. What do you understand by jitter associated with a periodic task? What caused this trembling? How to overcome them?
43. Divide existing real-time task scheduling algorithms into several broad classes. Explain important features of these broad classes of task scheduling algorithms.
44. Explain the difference between clock-driven, event-driven schedulers and hybrid schedulers for real-time tasks. Which scheduler type is preferred for scheduling three periodic tasks in an embedded application. Justify the answer.
45. Explain the problems that might arise if hard real-time tasks share critical resources among themselves using traditional operating system primitives such as semaphores or monitors. Briefly explain how these problems can be solved.
46. ​​What do you understand by the term "priority inversion" in the context of real-time task scheduling? (chapter 3)
47. Define the terms "priority inversion" and "unlimited priority inversion" that are used in real-time operating systems. (chapter 3)
48. Despite the fact that the clock speed of modern processors is on the order of several GHz, why do not many modern real-time operating systems support clock speeds with nanosecond or microsecond resolution? Can an operating system even support clock speeds with nanosecond resolution nowadays? Explain how this can be achieved? (chapter 5)
49. What is the difference between synchronous I/O and asynchronous I/O? What are the implications of these two types of I/O for real-time applications? (chapter 5)
50. What do you understand by memory protection in the language of the operating system. Compare the pros and cons of requiring an embedded real-time operating system (RTOS) to support memory protection?
51. What is the difference between block I/O and character I/O? For each I/O type, provide an example of a task that should use it. What type of I/O has higher priority in Unix? Why?
52. What is a watchdog timer? Explain the use of the watchdog timer with an example.
53. What is virtual memory? What options for organizing virtual memory do you know?
54. What problems can you highlight when using virtual memory in real-time systems?
55. In a hard real time system, is it necessary for every task in the system to be in hard real time? Explain your answer with a suitable example.
56. Give an example of a soft real-time task and a non-real-time task. Explain the key difference between the characteristics of these two task types.
57. Identify key differences between hard real-time systems, soft real-time systems, and hard real-time systems. Give at least one example of a real-time task that fits into these three categories. Define time constraints on your tasks and explain why tasks should be assigned to the categories you specified.
58. What is a "microcontroller"? What is its core made of? function block?
59. How is the specialization of microcontrollers?
60. Tell us about the classification of computing systems used to implement real-time systems.
61. What types of computer performance do you know?
62. Describe the two main problems due to which the operating systems of the Unix family cannot be used to develop hard real-time systems.
63. How are the disadvantages of the traditional Unix kernel: non-preemptive (or non-preemptive) kernel and dynamic priority values ​​resolved in standalone host systems?
64. What is a real-time host system and what is it used for?
65. What is a standalone real-time host system?
66. Describe approaches to organizing the distribution of computer memory in multitasking mode.
67. What is virtual memory?
68. How is the paging organization of virtual memory?
69. What problems arise when using paging?
70. How is the segment organization of memory arranged?
71. How does the segment-page organization of memory work?
72. What problems arise when using segmented addressing?
73. What problems arise when using virtual memory?
74. What are the design features of real-time systems that are not found in the design of general-purpose systems?
75. What is a general requirement for a security critical application?
76. Model-based design and component-based design are two different design strategies. What are the differences?
77. Why is the concept of a component, a hardware-software unit, introduced as the basic building block of a system? What are the problems with the concept of a software component in the context of real-time system design?
78. Explain the difference between a standard PC operating system and an RT operating system in a security-critical real-time application node!
79. Give a brief description of the DO-178B standard.
80. Explain why in real-time systems it is recommended to adhere to the POSIX standard.
81. What standards of real-time systems did you get acquainted with on the course? Give them a brief description and indicate what they are for.
82. What is cooperative and preemptive multitasking? What are the main states of a process?
83. Describe the mechanism of semaphores
84. What are semaphore operations? What is their scope?
85. What typical synchronization tasks do you know?
86. What are interruptions? What are they needed for? How are interrupts handled on x86 processors?
87. How is the maintenance of processes without priorities and with priorities organized?
88. Why is precedence inheritance introduced? What is priority inversion? What might cause it to appear?
89. What are dead ends? What are they like?
90. Formulate the main conditions for the occurrence of deadlocks. What methods of dealing with deadlocks do you know?
91. What RTOS do know? Describe them.
92. What are the advantages of object-oriented RTOS?
93. Is it possible to use Linux OS in real time tasks? With what restrictions?
94. For what tasks of RT are Windows operating systems suitable?
95. Describe the features of the QNX OS and explain why it is well suited for an autonomous underwater robot.
96. What methods of specification and design of real-time systems do you know? Describe them briefly.
97. What are the main types of real-time systems do you know?
98. Why is sampling time important? What does this setting affect?
99. What approaches are used to reduce the overall execution time of tasks
100. What real-time operating systems do you know? Give a brief description of at least three RTOS, indicating in which real-time systems they were used.