• Bell Labs (AT&T) UNIX licenses cost $30,000 for commercial use, $150 for Universities.
• Berkeley UNIX was free and would boot directly, so there was no need for the Bell Labs tape.
• Berkeley UNIX contained Bell source code, so you had to have a UNIX license to get it.
• Armando Stettner of DEC’s tounge-in-cheek solution to the dilemma was to create UNIX licenses (license plates) and hand them out for free in 1982.
• The Stargate Museum includes a UNIX license plate from Armando.
The full story can be found at http://www.unix.org/license-plate.html