Written at Texas Instruments. Runs on MS-DOS 286/386 IBM PCs and compatibles. Includes an optimising compiler, an emacs-like editor, inspector, debugger, performance testing, foreign function interface, window system and an object-oriented subsystem. Also supports the dialect used in Hal Abelson and Gerald Sussman's SICP. Conformance: Revised^3 Report, also supports dialect used in SICP. See also PCS/Geneva.