Computer science fundamentals · Lesson 40 of 60 · Concept lesson · Optional

Computer architecture

The CPU runs instructions, memory (RAM) holds the data and programs in use right now, and storage keeps data when the power is off.

The CPU is much faster than memory, and memory is much faster than storage, so computers keep recently used data close by in caches.

A program's instructions are fetched, decoded and executed, over and over.

Picture it

CPU --> cache --> RAM --> disk

left:  fast, small, costly
right: slow, large, cheap

The memory hierarchy. The closer to the CPU, the faster and smaller the memory is, and the further away, the slower and larger it gets.

Pick an answer for each question. You can retry as many times as you like.

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