The earliest microcomputers, like the MITS Altair 8800, generally had no built-in input/output (I/O) beyond front-panel switches and LED lamps. Useful work generally required the addition of an I/O expansion card and the use of some form of terminal. At the time, video-based terminals were very expensive, costing much more than the computer, so many users turned to mechanical devices like the Teletype Model 33. The Model 33, like most teleprinters of the era, included a tape punch system intended to allow operators to pre-record their messages and then play them at "high speed", faster than most individuals could type the message live. For the early microcomputers, this provided a convenient computer data storage format, allowing the users to write programs to paper tape and distribute them to other users.
