Introduction to U/W-Focal for the PDP/8

Summary

This document serves as an instruction manual for U/W-FOCAL (UWF), a powerful, interactive programming language designed for the PDP/8 computer. UWF is an advanced version of FOCAL that is modeled after BASIC and FORTRAN but is designed to be easier to use, featuring a stack-processing architecture and a built-in editor.

Key sections of the manual include:

• System Setup: Instructions for hardware requirements, loading the UWF binary tape, and initial program configuration using the switch register.
• Command Modes: Explanations of direct (immediate) versus indirect (stored) commands, line numbering, and the use of the built-in editor for modifying or moving program lines.
• Syntax and Variables: Details on input/output commands (ASK and TYPE), variable naming conventions, the symbol table, protected "secret" variables, and subscripted variables for linear algebra.
• Arithmetic and Control: Documentation of arithmetic operators, priority of operations, and flow control commands (GOTO, DO, IF, ON, JUMP, LINK, QUIT).
• Looping: A guide to constructing loops using the FOR, NEXT, and BREAK commands.
• Input/Output: Management of I/O devices (tape reader, punch, terminal) and advanced formatting options.
• Internal Functions: A library of built-in functions, including trigonometric, logarithmic, and character-processing functions, as well as the ability to define custom functions (PDFs).
• Advanced Features: Instructions for the KONTROL command (for DR8-EA modules) and FPAL (for integrating machine-language routines).

The manual concludes with technical appendices detailing error codes and patches for custom feature implementation.