Development of the personal computer (PC), a microcomputer designed to be used by one person, was first developed for business use in the early 1970s. Digital Equipment Corporation developed the PDP-8, which was predominately used in scientific laboratories. The credit for development of a computer for home use goes to Steve Wozniak (1950-) and Steve Jobs (1955-), college dropouts who founded Apple Computer in 1976. They spent six months working out of a garage, developing the crude prototype for Apple I, which was bought by some 600 hobbyists—who had to know how to wire, program, and set up the machine. Its successor, Apple II, was introduced in 1977 as the first fully assembled, programmable microcomputer, but it still required customers to use their televisions as screens and to use audio cassettes for data storage. It retailed for just less than $1,300. That same year Commodore and Tandy introduced affordable personal computers. In 1984 Apple Computer introduced the Macintosh (Mac), which became the first widely used computer with a graphical user interface (GUI). By this time, International Business Machines (IBM) had introduced its PC (1981), which quickly overtook the Mac, in spite of the fact that IBM was behind in developing a user-friendly graphical interface.