PDP-12 System Reference Manual

This document serves as a comprehensive system reference manual for the Digital Equipment Corporation PDP-12, a versatile digital computer featuring two distinct operating modes: LINC (Laboratory Instrument Computer) and PDP-8. It outlines the computer's core architecture, including a single central processor with a 12-bit word length and a 1.6-microsecond cycle time, offering 4K (expandable to 32K) words of core memory. Both operating modes have equal status, allowing programs to switch between them and utilize their respective instruction sets.

The manual details the PDP-12's various components and capabilities, such as the central processor's registers (e.g., Accumulator, Program Counter, Memory Buffer), memory organization (divided into segments in LINC mode and pages in 8 mode), and extensive input/output facilities. These I/O capabilities include a CRT display, a data terminal with analog inputs and relays, LINCtape transports, and a flexible I/O bus supporting a wide range of peripheral devices like the Extended Arithmetic Element (EAE), real-time clocks, disk storage, magnetic tape, line printers, and card readers.

Detailed programming information is provided for both LINC and 8 modes, covering instruction formats, data transfers, arithmetic, logical operations, program control, skips, and interrupt handling. The document also describes the physical controls and indicators on the console, CRT display, LINCtape transport, and Teletype Model 33 ASR. A significant portion is dedicated to comprehensive descriptions of peripheral devices, their functionalities, specifications, and associated IOT (Input/Output Transfer) instructions. Finally, the manual includes a program library listing available PDP-12 and PDP-8 software, such as assemblers (LAP6-DIAL), compilers (FORTRAN, FOCAL), debuggers, utility routines, and diagnostic programs, along with appendices detailing instruction sets, code tables, and interface connection diagrams.