FOCAL-12

This manual describes FOCAL-12, an expanded version of DEC's FOCAL language specifically designed for the PDP-12 computer. It optimizes the use of standard peripheral devices such as LINCtape, disks, display scope, A/D channels, and real-time clock, facilitating data acquisition, reduction, and analysis. The minimum system requires a PDP-12B with 8K core memory.

Key features include the FDIS function for plotting points on the VR12 display and new OUTPUT commands (SCOPE, TELETYPE, DELAY, CLEAR, ERASE) to manage display output. Data storage and retrieval are handled through LIBRARY MAKE, OPEN, and CLOSE commands for named binary files or absolute block numbers on LINCtape or disk, supporting signed integer, signed fraction, and floating-point formats. Programs can be saved and loaded using LIBRARY SAVE, LOAD, and GO commands, with LIBRARY GO also enabling program segmentation.

FOCAL-12 supports analogue input via the FADC(n) command for sampling up to 32 channels and timing with the OUTPUT INTERVAL command using the KW12A clock. Various data acquisition methods are discussed, including storing data in memory, on LINCtape, and on disk, with the $THRUFØ user function allowing higher throughput for LINCtape acquisition. The system also supports user-defined machine language subroutines (FNEW, FX, FZ) to extend its functionality, detailing how to implement and manage these overlays. Appendices provide summaries of commands, functions, startup procedures, data formats, I/O specifics, and error diagnostics.