As schools acquire and use computers for educational purposes, two major questions arise: (1) whether students from different strata of society will obtain equal access to computers, and (2) whether students from different strata of society will be taught similar or different uses of the computer. To explore the relationship between the characteristics of schools, the students they educate, and students' access to computers, observations of computer use were conducted in 21 classrooms in five Southern California School Districts. A very strong relationship was found between the type of students who are being educated using computers and the type of instruction that is being presented to them. Boys and girls had differential access to computers, especially in secondary schools. (In elementary schools with central lab facilities, girls and boys had equal access.) Ethnic minority and lower class students received a different kind of instruction than did their white middle class and ethnic majority contemporaries. White middle class students received instruction which encouraged learned initiative (programming and problem solving). Lower class and ethnic minority students received instruction which maintained control of learning in the computer (computer aided drill and practice). Basic computer literacy courses emphasize programming, but increasingly employers are seeking individuals with skills in applications such as word processing, spreadsheet analysis, and data systems management. Typically, only students who progress to advanced courses learn these skills. Ethnic minorities are often excluded. Serious consideration of these policies is necessary to avoid a system of stratification based on access to information technology. (25 references) (GL)