This paper describes the implementation of educational computing in three schools located in the suburban belt of a large metropolis. One school included grades K-6; one grades 5-6; and one grades 7-8. The schools were similar in that they were well financed and the staff and students felt they were doing well; however, they were different in the ethnic composition and socioeconomic level of their student bodies. All three schools provided inservice training for their teachers and purchased hardware and software. It was found that the distinctive features of each school conditioned the extent of computer use and shaped the form and substance of the educational computing program at the initial stages of implementation. The strongest determinants of the kind of computer activities implemented and the relationship between computer activities and other school work were found to be the staff's perceptions of the student body and what constitutes legitimate school knowledge, together with the style of student supervision. (30 references) (Author/EW)