30 Lecture

1. What is interrupt priority? a) The order in which interrupts are received b) The order in which interrupts are serviced c) The time it takes to service an interrupt d) The number of interrupts that can be handled at once Answer: b) The order in which interrupts are serviced What is the purpose of interrupt priority? a) To ensure that all interrupts are handled equally b) To reduce the number of interrupts c) To determine the order in which interrupts are serviced d) To prevent nested interrupts Answer: c) To determine the order in which interrupts are serviced What is a nested interrupt? a) An interrupt that occurs before the previous interrupt is serviced b) An interrupt that occurs after the previous interrupt is serviced c) An interrupt that occurs during the servicing of another interrupt d) An interrupt that occurs when no other interrupts are pending Answer: c) An interrupt that occurs during the servicing of another interrupt What happens when a nested interrupt occurs? a) The processor ignores the nested interrupt b) The processor services the nested interrupt immediately c) The processor completes the current interrupt before servicing the nested interrupt d) The processor reboots the system Answer: c) The processor completes the current interrupt before servicing the nested interrupt What is interrupt masking? a) Disabling interrupts temporarily b) Enabling interrupts temporarily c) Assigning priorities to interrupts d) Suspending the current interrupt Answer: a) Disabling interrupts temporarily Which of the following is true regarding interrupt priorities? a) Higher priority interrupts are always serviced first b) Lower priority interrupts are always serviced first c) Interrupts are serviced in a random order d) Interrupts are serviced in the order they are received Answer: a) Higher priority interrupts are always serviced first Which of the following is a disadvantage of nested interrupts? a) They can cause delays in the servicing of lower priority interrupts b) They can cause system crashes c) They can increase the processing time of interrupts d) They can decrease the system performance Answer: a) They can cause delays in the servicing of lower priority interrupts Which of the following is a technique used to handle interrupt priorities? a) Interrupt masking b) Interrupt chaining c) Interrupt queuing d) Interrupt reordering Answer: b) Interrupt chaining What is the maximum number of interrupt levels supported by most processors? a) 8 b) 16 c) 32 d) 64 Answer: c) 32 What is the purpose of an interrupt vector table? a) To store the priority levels of interrupts b) To store the addresses of interrupt service routines c) To store the names of interrupts d) To store the number of interrupts Answer: b) To store the addresses of interrupt service routines
   

1. What is interrupt priority, and why is it important? Answer: Interrupt priority is the order in which interrupts are serviced by the processor. It is essential to ensure that higher-priority interrupts are serviced first, as they may represent critical events that require immediate attention. What is the difference between a hardware interrupt and a software interrupt? Answer: A hardware interrupt is triggered by an external device or event, while a software interrupt is generated by a program running on the processor. What is the purpose of interrupt masking? Answer: Interrupt masking is a technique used to temporarily disable interrupts to prevent them from being serviced while critical operations are being performed. What is interrupt chaining, and how is it used? Answer: Interrupt chaining is a technique used to handle nested interrupts. When a nested interrupt occurs, the processor saves the current interrupt context and chains the new interrupt to the current one. When the new interrupt is serviced, the processor returns to the previous interrupt context and resumes the interrupted task. What is a priority inversion, and how can it be avoided? Answer: A priority inversion occurs when a low-priority task holds a resource needed by a higher-priority task, causing the higher-priority task to be blocked. To avoid priority inversion, resources should be allocated and released in a way that ensures that higher-priority tasks have priority access to them. What is an interrupt vector table? Answer: An interrupt vector table is a table that stores the addresses of the interrupt service routines for each interrupt type. When an interrupt occurs, the processor looks up the address of the appropriate service routine in the vector table. What is the difference between a level-triggered interrupt and an edge-triggered interrupt? Answer: A level-triggered interrupt is active as long as the triggering condition is present, while an edge-triggered interrupt is triggered by a specific transition of the triggering signal. How can interrupt priorities be assigned in a system with multiple processors? Answer: Interrupt priorities can be assigned on a per-processor basis or using a global interrupt controller that coordinates interrupt handling across multiple processors. What is interrupt latency, and why is it important? Answer: Interrupt latency is the time delay between the occurrence of an interrupt and the start of its servicing. It is important to minimize interrupt latency to ensure timely response to critical events. What is the role of interrupt service routines, and how are they implemented? Answer: Interrupt service routines are functions that handle interrupts by performing the necessary tasks to respond to the event. They are implemented in a low-level language and typically have restricted access to system resources to ensure their safety and efficiency.
   

Interrupts are a crucial feature of modern computer systems that allow the processor to respond to external events quickly. Interrupts can be classified into two main categories: hardware interrupts and software interrupts. Interrupts can also be prioritized based on their criticality, and the system can handle multiple interrupts simultaneously by using a technique called interrupt nesting. Interrupt priority refers to the order in which interrupts are serviced by the processor. The system can prioritize interrupts to ensure that high-priority events are processed first, while low-priority events are serviced later. Interrupt priority is critical to ensure that the system can respond to critical events quickly and efficiently. Interrupt masking is another technique that can be used to control the handling of interrupts. Interrupt masking allows the system to temporarily disable interrupts to prevent them from being serviced while critical operations are being performed. This technique is useful when multiple interrupts occur simultaneously, and the system needs to prioritize them based on their criticality. Interrupt chaining is a technique used to handle nested interrupts. When a nested interrupt occurs, the processor saves the current interrupt context and chains the new interrupt to the current one. When the new interrupt is serviced, the processor returns to the previous interrupt context and resumes the interrupted task. This technique allows the system to handle multiple interrupts simultaneously while maintaining the correct order of execution. Interrupt vector tables are used to store the addresses of the interrupt service routines for each interrupt type. When an interrupt occurs, the processor looks up the address of the appropriate service routine in the vector table. The interrupt service routines are functions that handle interrupts by performing the necessary tasks to respond to the event. These routines are implemented in a low-level language and typically have restricted access to system resources to ensure their safety and efficiency. Interrupt latency is the time delay between the occurrence of an interrupt and the start of its servicing. Interrupt latency is a critical factor in ensuring that the system can respond to critical events quickly and efficiently. Techniques such as interrupt masking and interrupt chaining can be used to minimize interrupt latency. In summary, interrupt priority and nested interrupts are critical features of modern computer systems that allow the system to respond quickly to external events. These techniques are used to ensure that the system can handle multiple interrupts simultaneously while maintaining the correct order of execution. Interrupt vector tables and interrupt service routines are essential components of the interrupt handling process, while interrupt latency is a critical factor in ensuring that the system can respond to critical events quickly and efficiently.