More than 225 of the 1930s Columbia Workshop and its 1946-47 revival are available on tape. That this was not a show for the masses is especially true today. Some of these shows, on first listening, seem to move at a glacial pace; some seem quite old and dated. The techniques they pioneered have become so routine, their high-tech counterparts bombarding people in radio commercials around the clock, that a listener seldom gives a thought to a time when they didn't exist.