Computer Structures: What Have We Learned from the PDP-11?

This document provides a retrospective analysis of the PDP-11 computer, focusing on lessons learned over its first six years of existence (1969-1975). It covers the design motivations, the importance of environment (technology, organization, and market) in system architecture, and specific technical features like the UNIBUS. The summary highlights how the PDP-11's architecture evolved to handle constraints like limited address space and register counts, and examines the challenges of designing a range of compatible models under asynchronous planning. It also discusses the impact of semiconductor technology and the complexities of multiprocessor structures implemented on the PDP-11 base.