“foo”, “bar”, “foobar” 的意思

在許多RFC文檔或者代碼例子中包含"foo", "bar", "foobar", 今天突然想知道這些詞彙的來源以及含義, 在網上搜了一下, 大概明白了一些

 

 

http://zh.wikipedia.org/zh/Foobar

 

 在電腦程式設計與電腦技術的相關文檔中，術語foobar是一個常見的無名氏化名，常被作為“偽變數”使用。

 

從技術上講，“foobar”很可能在1960年代至1970年代初通過迪吉多的系統手冊傳播開來。另一種說法是，“foobar”可能來源於電子學中反轉的foo訊號（）；這是因為如果一個數字訊號是低電平有效（即負壓或零電壓代表“1”），那麼在訊號標記上方一般會標有一根水平橫線，而橫線的英文即為“bar”。在《新駭客辭典》中，還提到“foo”可能早於“FUBAR”出現。^[1]

 

http://www.catb.org/jargon/html/F/foobar.html

 

foobar: n.

[very common] Another widely used metasyntactic variable; see foo for etymology. Probably originally propagated through DECsystem manuals by Digital Equipment Corporation (DEC) in 1960s and early 1970s; confirmed sightings there go back to 1972. Hackers do not generally use this to mean FUBAR in either the slang or jargon sense. See also Fred Foobar. In RFC1639, “FOOBAR” was made an abbreviation for “FTP Operation Over Big Address Records”, but this was an obvious backronym. It has been plausibly suggested that “foobar” spread among early computer engineers partly because of FUBAR and partly because “foo bar” parses in electronics techspeak as an inverted foo signal; if a digital signal is active low (so a negative or zero-voltage condition represents a "1") then a horizontal bar is commonly placed over the signal label.