Interrupt vectoring

Definition

Interrupt vectoring is a mechanism used by computer systems to efficiently handle interrupts by providing a way to quickly determine the appropriate service routine for each type of interrupt. This process involves using a table, known as the interrupt vector table, which contains addresses for different interrupt handlers. When an interrupt occurs, the system can reference this table to find and execute the correct handler, minimizing latency and improving overall performance in interrupt handling.

5 Must Know Facts For Your Next Test

1. Interrupt vectoring reduces the time taken to respond to interrupts by directly mapping them to their handlers through the interrupt vector table.
2. The process allows for dynamic handling of multiple interrupt types, enabling efficient prioritization and execution of service routines.
3. Systems can support both hardware and software interrupts, with vectoring providing a standardized method for both types.
4. In modern systems, hardware often supports multiple levels of interrupts, allowing for nested interrupts handled via their respective vectors.
5. Proper configuration of the interrupt vector table is crucial for system stability, as incorrect mappings can lead to undefined behavior or crashes.

Review Questions

• How does interrupt vectoring improve the efficiency of handling multiple interrupts in a computer system?
  • Interrupt vectoring enhances efficiency by providing a direct mapping from each type of interrupt to its corresponding service routine through the interrupt vector table. When an interrupt occurs, the system can quickly access the right handler without searching through all possible routines. This quick lookup significantly reduces latency and allows for better management of simultaneous interrupts, ensuring that high-priority tasks are addressed promptly.
• Discuss the potential issues that could arise if an interrupt vector table is incorrectly configured.
  • If an interrupt vector table is misconfigured, it can lead to several serious issues such as incorrect execution of service routines or even system crashes. For example, if an interrupt is mapped to a non-existent handler or an unrelated routine, it may cause unexpected behavior or system instability. Additionally, priority levels assigned within the table could lead to critical interrupts being ignored or delayed if not properly set, disrupting system performance and reliability.
• Evaluate the role of interrupt vectoring in modern operating systems and how it adapts to new computing paradigms such as multi-core processors.
  • In modern operating systems, interrupt vectoring plays a crucial role in managing complex tasks across multi-core processors. By providing a structured way to handle interrupts efficiently, systems can delegate specific handlers to different cores, enabling parallel processing and better resource utilization. As applications become more demanding and require real-time responses, robust interrupt handling via vectoring ensures that even with multiple threads and processes running simultaneously, interrupts are managed swiftly and effectively, keeping systems responsive under load.

Related terms

Interrupt Service Routine (ISR): A special block of code that executes in response to an interrupt signal, handling the necessary operations required by the interrupting device.

Interrupt Vector Table (IVT): A data structure that holds the addresses of ISRs for different types of interrupts, allowing the system to quickly locate the correct handler.

Polling:

A method where the CPU repeatedly checks the status of devices to determine if they need servicing, as opposed to using interrupts.