vi is a text editor written by Bill Joy (co-founder Sun Microsystems) in 1976 for an early BSD oses. Some of his most notable contributions were TCP/IP, the vi editor, NFS, and the csh shell.
There is new article/interview at The Register with Bill Joy -
"Bill's greatest gift to mankind was left off his list of achievements (in your article)... the vi editor," writes reader Matthew Hawkins in Australia. "I can live without NFS, Java and related technologies. I'm not sure if I can live without vi." .. 9600 baud is faster than you can read. 1200 baud is way slower. So the editor was optimized so that you could edit and feel productive when it was painting slower than you could think. Now that computers are so much faster than you can think, nobody understands this anymore.