Related:

• ar and feather vi. [from Unix tar(1)] To create a transportable archive from a group of files by first sticking them together with tar(1) (the Tape ARchiver) and then compressing the result (see compress).
  The latter action is dubbed `feathering' partly for euphony and (if only for contrived effect) by analogy to what you do with an airplane propeller to decrease wind resistance, or with an oar to reduce water resistance...
• magic number n. [Unix/C; common] 1. In source code
  some non-obvious constant whose value is significant to the operation of a program and that is inserted inconspicuously in-line (hardcoded), rather than expanded in by a symbol set by a commented #define....
• foo /foo/ 1. interj. Term of disgust. 2. [very common] Used very generally as a sample name for absolutely anything, esp.
  programs and files (esp. scratch files). 3. First on the standard list of metasyntactic variables used in syntax examples....
• ar and feather: [from UNIX `tar(1)'] vt. To create a transportable archive from a group of files by first sticking them together with `tar(1)' (the Tape ARchiver) and then compressing the result (see {compress}).
  The latter action is dubbed `feathering' partly for euphony and (if only for contrived effect) by analogy to what you do with an airplane propeller to decrease wind resistance, or with an oar to reduce water resistance...
• back door n. [common] A hole in the security of a system deliberately left in place by designers or maintainers.
  The motivation for such holes is not always siniste...
• diff /dif/ n. 1. A change listing, especially giving differences between (and additions to) source code or documents (the term is often used in the plural `diffs').
  Send me your diffs for the Jargon File!" Compare vdiff....
• diff: /dif/ n. 1. A change listing, especially giving differences between (and additions to) source code or documents (the term is often used in the plural `diffs').
  Send me your diffs for the Jargon File!" Compare {vdiff}....
• mainframe n. Term originally referring to the cabinet containing the central processor unit or `main frame' of a room-filling Stone Age batch machine.
  After the emergence of smaller `minicomputer' designs in the early 1970s, the traditional big iron machines were described as `mainframe computers' and eventually just as mainframes....
• delta n. 1. [techspeak] A quantitative change, especially a small or incremental one (this use is general in physics and engineering).
  I just doubled the speed of my program!" "What was the delta on program size?...