U/W Focal

This document serves as a user manual for U/W FOCAL, an expanded version of the PS/8 FOCAL programming language developed by Jim van Zee at the University of Washington in 1978. Designed for OS/8 and OS/12 systems with at least 8K of memory, U/W FOCAL is optimized for laboratory applications and complex numerical analysis, featuring 10-digit precision and enhanced performance.

Key features and capabilities detailed in the manual include:

• Expanded Functionality: The inclusion of 13 new commands, 15 additional function entries, and "FOCAL Statement Functions," which allow subroutines to be called as functions.
• Advanced Data Handling: Support for double subscripting, variable file names, and improved I/O routines for high-speed paper tape and mass-storage devices.
• Graphics and Control: Specialized routines for driving Tektronix terminals, incremental plotters, and controlling external hardware via device handlers.
• Programming Utilities: Tools for merging programs, managing subroutines, and performing iterative calculations with real-time interrupt handling.
• Maintenance: The manual provides comprehensive documentation on adding new user-defined functions and commands, along with specific technical instructions for system patching (including a necessary "date fix" for calendar years beyond 1977).

The document is structured as a technical reference, containing a complete command index, a library of internal routines, and detailed appendices for error codes and hardware/software maintenance.