Program Your Minicomputer in Focal

Summary

"Program Your Minicomputer in FOCAL" introduces FOCAL (FOrmula CALculator), a high-level, conversational programming language designed specifically for small digital computers with limited core memory (4,000 words). Developed to be user-friendly for those without formal programming experience, FOCAL functions as an interpreter that enables minicomputers to perform complex tasks, including real-time data acquisition, laboratory control, and data analysis.

Key features of FOCAL include:

• Memory Efficiency: The language uses a mnemonic command structure that allows for either full or abbreviated commands to save core memory. It also utilizes semicolons to chain commands and reduce data overhead.
• Ease of Use: It features a natural, readable structure and a robust system of error diagnostics. A "trace" feature and a "modify" command allow users to quickly locate and fix programming mistakes.
• Flexibility: FOCAL supports a wide range of input/output formats, including floating-point math, alphanumeric string processing, and interactive plotting capabilities on teletypes.
• Dynamic Configuration: The language allows users to define the limits of the system upon loading, letting them choose which extended functions (like logarithms or exponentials) to include based on their specific memory needs.
• Asynchronous Operation: FOCAL can buffer data to and from input/output devices, allowing the computer to manage interactions with external equipment efficiently.

The article emphasizes that while FOCAL sacrifices some raw speed and cross-language compatibility to fit within tight memory constraints, it provides a powerful, highly flexible, and accessible tool for engineers and scientists to perform calculations and control laboratory equipment.