Preliminary Specifications: Programmed Data Processor Model Three (PDP-3) October, 1960

The book offers a clear, contemporary look at a groundbreaking early‑sixties computer, the Programmed Data Processor Model Three. It explains how DEC achieved a blend of high speed—up to two hundred thousand operations per second—and dependable, low‑cost operation by relying on fast solid‑state circuitry and a restrained, purpose‑driven design. Readers learn why the machine’s simplicity made it ideal for real‑time control tasks and for serving as the heart of a modern computing facility.

Inside, the manual walks through the PDP‑3’s architecture in detail, from its 36‑bit registers and memory buffer to the accumulator, carry storage, and I/O pathways. It describes the memory hierarchy built on magnetic core modules, the indexing and indirect addressing mechanisms, and the control element that orchestrates instruction decoding. With diagrams and concise explanations, the text serves engineers, historians, and enthusiasts who want to understand how this early system balanced performance, expandability, and reliability.