1970–1972

During the early 1970s, UNIX began to gain popularity throughout Bell Labs, and as word of the new operating system spread, universities embraced it. Although UNIX was viewed favorably by the academic and high-tech sectors, however, it was met with skepticism by the business community. In a move to heighten the popularity of UNIX, AT&T began to license the UNIX source code to universities at a minimal cost. AT&T gave many licensees the software code and manuals but didn’t provide technical support. By the late 1970s, 70 percent of all colleges and universities had UNIX. Computer science graduates were using it, even modifying the code to make it more robust. UNIX was written in assembly language and ran primarily on DEC hardware—first on the PDP-7 and then the PDP-11/40, the 11/45, and finally the 11/70, on which it gained wide popularity.