Expensive Tape Recorder is a digital audio program written by David Gross while a student at the Massachusetts Institute of Technology.
Gross developed the idea with Alan Kotok, a fellow member of the Tech Model Railroad Club.
They were able to increment the X axis to produce a live display on the CRT during playback.According to Kotok, the project was "digital recording more than 20 years ahead of its time."
In 1984, when Jack Dennis asked if they could recognize Beethoven, Computer Museum meeting minutes record the authors as saying, "It wasn't bad, considering."
Digital audio pioneer Thomas Stockham worked with Dennis and like Kotok helped develop a contemporary debugger.