<aside> 👇 An interrupt is a signal sent to the processor by another part of the computer requesting its attention

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• Allow the CPU to make much more efficient use of its time

Examples

Hardware

• Printer sends interrupts to spooling system
• Terminals send interrupts if key pressed/mouse clicked
• Disk drive data transfer completed
• Power failure

Software

• Clock sends interrupt at the end of the time slice
• Disk controller sends interrupt when file transfer completed
• Processor sends interrupt if a software error occurs
• Maths error (i.e. division by 0)
• File handling error (e.g. file not found)
• Execution of program completed
• User termination of program (CTRL/ALT/DEL)

Priority levels

High: mouse click

Medium: backing up to the cloud

Low: update to software