PDP-12 LAP 6-DIAL Programmer's Reference Manual

This document serves as a reference manual for LAP6-DIAL (DIAL), a keyboard operating system designed for the Digital Equipment Corporation PDP-12 computer. DIAL provides comprehensive capabilities including editing, assembling, and file handling, utilizing an interactive CRT display and LINCtape for storage.

The system requires a PDP-12B with 4096-word memory and LINCtape transports, starting in edit mode where programs can be typed, modified, or deleted. The DIAL Editor offers flexible cursor control for character, line, and large section editing, and automatically formats input into tag, instruction, and comment fields. It supports programs up to 64 blocks long, with tools like SAVSYM and LODSYM pseudo-operators to manage larger programs by splitting them into sections and sharing symbol tables.

The DIAL Assembler translates mnemonic operation codes into binary, assigns absolute core addresses, and provides listings with error messages. It supports both LINC and PDP-8 programming modes, defined by pseudo-operators like LMODE and PMODE. It manages user-defined symbols, numeric interpretations (octal or decimal), and expressions with arithmetic and logical operators. Key pseudo-operators include SEGMNT for memory segment control, NOLIST/LIST for output control, TEXT for character strings, and conditional assembly directives (ASMIFx, ASMSKP).

File management is tape-oriented, with a central Index storing file names, starting blocks, and lengths. Commands are issued via the Teletype keyboard to perform operations such as assembling (AS, LI, QL), saving and loading binary (SB, LO) or source programs (SP, AP), displaying and printing the file index (DX, PX), and clearing the working area (CL). The Peripheral Interchange Program (PIP) (PI) facilitates file transfers between various I/O devices (LINC tape, paper tape, card reader, line printer) in auxiliary, binary, or source modes.

The manual also includes a detailed initial starting procedure, a list of assembly error messages, and summaries of commands, pseudo-operators, character sets, and PDP-8/LINC instructions, along with diagrams illustrating tape allocation and workflow.