This document provides an overview of computer memory and cache memory. It discusses key memory parameters like access type, capacity, cycle time, latency, bandwidth and cost. It describes the concepts of locality of reference, including spatial and temporal locality. Cache memory is introduced to take advantage of locality by moving frequently accessed data and instructions from slower main memory to a faster cache. The document outlines different cache memory mapping techniques including direct mapping, which uses a simple fixed formula to map blocks of main memory to the cache.