These PROCs and FUNCS were originally specified in COMAL Today issue 26, pages 33-34.
COMPUTER'COMAL: returns a number that identifies what COMAL is running. 5 is OpenCOMAL.
OPENCOMAL: returns 5.
COMPUTER'DRIVE$(x): returns drives that are safe to use, at least for x = 0 and 1.
COMPUTER'SCREEN$: returns the name for the screen, for use with the SELECT statement.
COMPUTER'RVSON: turns on reverse video in PRINT statements.
COMPUTER'RVSOFF: turns off reverse video in PRINT statements.
COMPUTER'EOL$: returns the proper EOL character(s).