do so for many years. Coulouris considered the cryptic commands of ed to be only suitable for "immortals", and thus in February 1976, he enhanced ed (using Ken Thompson's ed source as a starting point) to make em (the "editor for mortals") while acting as a lecturer at Queen Mary College. The em editor was designed for display terminals and was a single-line-at-a-time visual editor. It was one of the first programs on Unix to make heavy use of "raw terminal input mode", in which the running program, rather than the terminal device driver, handled all keystrokes. When Coulouris visited UC Berkeley in the summer of 1976, he brought a DECtape containing em, and showed the editor to various people. Some people considered this new kind of editor to be a potential resource hog, but others, including Bill Joy, were impressed. Inspired by em, and by their own tweaks to ed, Bill Joy and Chuck Haley, both graduate students at UC Berkeley, took code from em to make en, and then "extended" en to create ex version 0.1. After Haley's departure, Bruce Englar encouraged Joy to redesign the editor, which he did June through October 1977 adding a full-screen visual mode to exwhich came to be vi. vi and ex share their code; vi is the ex binary launching with the capability to render the text being edited onto a computer terminalit is ex's visual mode. The name vi comes from the abbreviated ex command (vi) to enter the visual mode from within it. The longform command to do the same was visual, and the name vi is explained as a contraction of visual in later literature. vi is also the shell command to launch ex/vi in the visual mode directly, from within a shell. According to Joy, many of the ideas in this visual mode were taken from Bravothe bimodal text editor developed at Xerox PARC for the Alto. In an interview about vi's origins, Joy said: A lot of the ideas for the screen editing mode were stolen from a Bravo manual I surreptitiously looked at and copied. Dot is really the double-escape from Bravo, the redo command. Most of the stuff was stolen. There were some things stolen from ed—we got a manual page for the Toronto version of ed, which I think Rob Pike had something to do with. We took some of the regular expression