This document discusses different types of computer memory including primary memory (RAM and ROM), secondary storage (hard drives, CDs, DVDs, etc.), and cache memory. RAM is volatile and used for temporary storage of data and programs needed to run the computer. ROM is non-volatile and holds the operating system bootstrap loader. Cache memory improves performance by storing frequently used data and instructions closer to the processor. Secondary storage devices include hard drives, optical discs, USB drives, and solid state drives which are used for long-term and offline storage of data.