Computer retailers and manufacturers have found providing appropriate instruction to be an essential part of marketing and selling their products. Most computer stores have classrooms in which courses are offered, providing an informal, interactive atmosphere for the instruction. The microcomputer market has split into two major segments: the personal and professional markets. Computers are marketed differently to these segments, and much more instruction is provided to the latter. Computer centers in Sears and Macy's offer demonstration disks and free instruction. Texas Instruments retail outlets, and ComputerLand and Radio Shack computer centers offer individual and class instruction as well as on-site training. Corporate approaches to computer literacy include Digital's computer-based, interactive, self-paced instruction through its Educational Services Division; Xerox's seminars; and Control Data's sale of educational services through various subsidiaries. Two physical characteristics that might affect learning in a computer school are density and privacy. Retail stores are not schools because they lack elements essential to an environment for disciplined learning--an authority structure that makes students subordinate to teachers, a formal method of evaluation, externally imposed incentives, and rewards. The instruction offered is a service rather than schooling. (YLB)