Focal-8

This document is a comprehensive programming manual for FOCAL-8, a service program developed by the Digital Equipment Corporation for the PDP-8 family of computers. FOCAL-8 (Formula Calculator) is an easy-to-learn language designed to help students, engineers, and scientists solve numerical problems.

The manual is structured as follows:

• Chapters 1–3: Introduces the system and details the FOCAL language, explaining commands, output formatting, arithmetic operations, and error detection.
• Chapter 4: Provides various demonstration programs for business, scientific, and educational applications, ranging from simple table generation to plotting and solving simultaneous equations.
• Chapter 5: Details advanced capabilities, including multi-user systems (QUAD and LIBRA), utility packages (4WORD and 8K), and graphics packages (CLINE).
• Appendices: Includes a command and operation summary, a comprehensive list of error messages, programming suggestions, and detailed loading procedures for various hardware configurations and the Disk Monitor System.

The manual concludes with an index for reference and a reader's comment page for user feedback.