Typesetting
During the mid-1970s Joseph Ossanna, working at Bell Laboratories, wrote the troff (said as "tee-roff") typesetting program to drive a Wang C/A/T phototypesetter owned by the Labs; it was later enhanced by Brian Kernighan to support output to different equipment such as laser printers and the like. While its use has fallen off, it is still included with a number of Unix and Unix-like systems and has been used to typeset a number of high-profile technical and computer books. Some versions, as well as a GNU work-alike called groff, are now open source.