Overview

Memory is as fundamental to computer architecture as any other element. The ability of a system's memory to transact the right quantity of data in the right span of time has a substantial impact on how that system fulfills its design goals. Digital engineers struggle with innovative ways to improve memory density and bandwidth in a way that is tailored to a specific application's performance and cost constraints.

Knowledge of prevailing memory technologies' strengths and weaknesses is a key requirement for designing digital systems. When memory architecture is chosen that complements the rest of the system, a successful design moves much closer to fruition. Conversely, inappropriate memory architecture can doom a good idea to the engineering doldrums of impracticality brought on by artificial complexity.

This chapter provides an introduction to various solid-state memory technologies and explains how they work from an internal structural perspective as well as an interface timing perspective. A memory's internal structure is important to an engineer, because it explains why that memory might be more suited for one application over another. Interface timing is where the rubber meets the road, because it defines how other elements in the system can access memory components' contents. The wrong interface on a memory chip can make it difficult for external logic such as a microprocessor to access that memory and still have time left over to perform the necessary processing on that data.

Basic memory organization and terminology are introduced first. This is followed by a discussion of...