I worked at Xerox in 1980, and we already had the GUI on the Alto server computer. Each employee had a personal hard drive that plugged into the Alto, customizing it for you. Everything in the office was connected with ethernet including all the printers. Xerox also sold a server called the Xerox Star, which I used in 1983 at Northrop in Anaheim. The Star cost about $25,000 so it didn't compete with the Macintosh. It competed with the Sun server. I don't know or care who did what first.