Interrupts
Computer Science: OCR A Level, topic 2.1.6
Interrupts
Interrupts are an essential part of modern computer systems that tell the CPU when something needs attention.
Interrupts
- An interrupt is a signal from a piece of software or hardware that tells the CPU that it needs some attention.
- Interrupts are an efficient way of telling a computer when a job needs to be completed.
Hardware interrupts
- Hardware interrupts can occur when an input or output operation completes.
- Hardware interrupts can also involve errors, like when a printer runs out of paper.
Software interrupts
- Software interrupts come from pieces of software that need to terminate or request services from the OS to complete a task.
- For example, opening a document.
Alternatives to interrupts
- One alternative to using interrupts is polling.
- Polling is when the CPU polls (asks) every piece of software and hardware if it needs anything doing.
- This would be a very inefficient process.
Test yourself on Interrupts
Which of the following processes does NOT produce a hardware interrupt?