Closed source means computer programs whose source code is not published except to licensees. Customers who developed software often made it available to others without charge. Computer vendors usually provided the source code for installed software to customers. Service and all software available were usually supplied by manufacturers without separate charge until 1969. Until the late 1960s computers-large and expensive mainframe computers, machines in specially air-conditioned computer rooms-were usually leased to customers rather than sold. Traditional use of copyright no rights need be granted
