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1. Fetch-Execute Cycle

CPUs carry out the tasks given to them in a particular way. First the instruction has to be 'fetched' from memory. Then the CPU has to 'decode' what it means. Once it does, it 'executes' the command. Then the process begins all over again.

fetch decode process cycle

This repeating process is a cycle. It is called the 'Fetch-Execute cycle' or the 'instruction cycle. We will be discussing the various parts of it in the following pages.