Itanium® Architecture for Programmers: Understanding 64-Bit Processors and EPIC Principles

13.1. Why Implementations Change

A new architecture can be novel only at its introduction. After the initial launch of a computer architecture, every subsequent implementation needs some fresh rationale, such as better performance, lower cost, or desirable features. Here, we try to avoid marketing rhetoric and instead elucidate the underlying requirements and scientific principles.

13.1.1. Demands and Opportunities

Processing early twentieth-century census data stimulated improvements in tabulating machines that worked with punch cards. The difficulty of decrypting enemy messages about operations in World War II stimulated the building of one of the earliest electronic computers. The inability of space launches to proceed if consensus is lost ...