FUBAR is an acronym that originated in the military to stand for the words "f***ed up beyond all repair." This is often softened to "fouled up beyond all repair" in reference to hardware. The programming and documentation equivalent is "fouled up beyond all recognition." Sometimes the last word is "recovery" or "reconciliation" or "reason."
In a Virtual Address Extension (VAX), the acronym FUBAR has been adapted to refer to the words "failed UniBus address register." Some programmers apparently managed to sneak this by humorless higher-ups, and the term stuck.
F.U.B.A.R. International is the name of a film company founded in 1989 by several businessmen seeking adventure. They went on location to film natural disasters. Some of the disasters were artificially created, especially avalanches, which could be triggered by explosives. Company executives vacation in Vail, Colorado every year, and have become local celebrities. These days, F.U.B.A.R. International markets clothing and novelty items.
Because foo , an unrelated term, appears phonetically in FUBAR, programmers have taken to using both foo and bar as metasyntactic variables when two such variables are needed.