FORTH for microcomputers

Forth is a unique threaded language ideally suited for microcomputers. Programs are incredibly compact; e.g. in 5K to 6K bytes you can get the interactive Forth compiler, running stand-alone as its own operating system including I/O drivers and other run-time routines, plus an assembler written in Forth (in case you want to optimize time-critical programs), virtual memory software, and a text editor. Not only does all this fit into 5K to 6K bytes (of which 4K are written in Forth), but it runs in the same space (plus 1K buffer), with no additional symbol table area, overlays, swapping, or use of any other software.And while Forth gives all the convenience of interactive interpreters, it is very fast. For most applications, the run-time overhead is 20 to 30% for minis and 70 to 100% for micros (compared to 1000% or more which is common for interpreters). Number-crunching applications may take longer. And when Forth isn't fast enough, the system's own assembler can be used to re-code inner loops.But the best news of all is that software development times are cut by half or more over assembly programming. The programming is entirely structured (there is no GOTO), and the resulting code is re-entrant and can be designed for PROM.Forth has been implemented on many microcomputers. A recommended configuration is 16K bytes and a terminal; a floppy is a good idea for storing source programs (and virtual memory for programs and data is supported). Forth works well with a CRT, so hard copy is less necessary.Forth has existed for several years, and is used commercially in a number of installations, but until recently it has been priced far out of reach of hobbyists, and even most computer experts have never heard of it. However, the language is in the public domain, and today low-cost versions are just becoming available. Also there is a new Forth Interest Group (787 Old County Rd, San Carlos, CA 94070), dedicated to letting the serious hobbyist and the professional know about Forth and how they can get it.