(1) The PDP-10 successor that was to have been built by the Super Foonly project at the Stanford Artificial Intelligence Laboratory along with a new operating system. (The name itself came from FOO NLI, an error message emitted by a PDP-10 assembler at SAIL meaning "FOO is Not a Legal Identifier". The intention was to leapfrog from the old DEC timesharing system SAIL was then running to a new generation, bypassing TENEX which at that time was the ARPANET standard. ARPA funding for both the Super Foonly and the new operating system was cut in 1974. Most of the design team went to DEC and contributed greatly to the design of the PDP-10 model KL10.
(2) The name of the company formed by Dave Poole, one of the principal Super Foonly designers, and one of hackerdom's more colorful personalities. Many people remember the parrot which sat on Poole's shoulder and was a regular companion.
(3) Any of the machines built by Poole's company. The first was the F-1 (a.k.a. Super Foonly), which was the computational engine used to create the graphics in the movie "TRON". The F-1 was the fastest PDP-10 ever built, but only one was ever made. The effort drained Foonly of its financial resources, and the company turned towards building smaller, slower, and much less expensive machines. Unfortunately, these ran not the popular TOPS-20 but a TENEX variant called Foonex; this seriously limited their market. Also, the machines shipped were actually wire-wrapped engineering prototypes requiring individual attention from more than usually competent site personnel, and thus had significant reliability problems. Poole's legendary temper and unwillingness to suffer fools gladly did not help matters. By the time of the Jupiter project cancellation in 1983, Foonly's proposal to build another F-1 was eclipsed by the Mars, and the company never quite recovered. See also Mars.