FOCL.S, an Expanded Language for Small Computers

FOCL/S is a superset of the FOCAL/69 programming language, specifically optimized for 8K PDP-8/12 systems. It introduces several enhancements, including support for up to 8 multiple subscripted array variables, direct core access, and machine language instruction execution to drive specialized hardware. The interpreter's memory layout has been modified to move text, variables, and the pushdown list to Field 1, which improves memory efficiency and allows for more user-defined functions in Field 0. This document provides a technical overview, including compatibility notes, array storage management, new command features like 'ON' and 'BRANCH', function expansions for the 'FX' command, and a detailed core map.