:filter: [orig. {{UNIX}}, now also in {{MS-DOS}}] n. A program that processes an input data stream into an output data stream in some well-defined way, and does no I/O to anywhere else except possibly on error conditions; one designed to be used as a stage in a `pipeline' (see {plumbing}).
:Finagle's Law: n. The generalized or `folk' version of {Murphy's Law}, fully named "Finagle's Law of Dynamic Negatives" and usually rendered "Anything that can go wrong, will". One variant favored among hackers is "The perversity of the Universe tends towards a maximum" (but see also {Hanlon's Razor}). The label `Finagle's Law' was popularized by SF author Larry Niven in several stories depicting a frontier culture of asteroid miners; this `Belter' culture professed a religion and/or running joke involving the worship of the dread god Finagle and his mad prophet Murphy.
:fine: [WPI] adj. Good, but not good enough to be {cuspy}. The word `fine' is used elsewhere, of course, but without the implicit comparison to the higher level implied by {cuspy}.
:finger: [WAITS, via BSD UNIX] 1. n. A program that displays a particular user or all users logged on the system or a remote system. Typically shows full name, last login time, idle time, terminal line, and terminal location (where applicable). May also display a {plan file} left by the user. 2. vt. To apply finger to a username. 3. vt. By extension, to check a human's current state by any means. "Foodp?" "T!" "OK, finger Lisa and see if she's idle." 4. Any picture (composed of ASCII characters) depicting `the finger'. Originally a humorous component of one's plan file to deter the curious fingerer (sense 2), it has entered the arsenal of some {flamer}s.
:finger-pointing syndrome: n. All-too-frequent result of bugs, esp. in new or experimental configurations. The hardware vendor points a finger at the software. The software vendor points a finger at the hardware. All the poor users get is the finger.
:finn: [IRC] v. To pull rank on somebody based on the amount of time one has spent on {IRC}. The term derives from the fact that IRC was originally written in Finland in 1987.
:firebottle: n. A large, primitive, power-hungry active electrical device, similar in function to a FET but constructed out of glass, metal, and vacuum. Characterized by high cost, low density, low reliability, high-temperature operation, and high power dissipation. Sometimes mistakenly called a `tube' in the U.S. or a `valve' in England; another hackish term is {glassfet}.
:firefighting: n. 1. What sysadmins have to do to correct sudden operational problems. An opposite of hacking. "Been hacking your new newsreader?" "No, a power glitch hosed the network and I spent the whole afternoon fighting fires." 2. The act of throwing lots of manpower and late nights at a project, esp. to get it out before deadline. See also {gang bang}, {Mongolian Hordes technique}; however, the term `firefighting' connotes that the effort is going into chasing bugs rather than adding features.
:firehose syndrome: n. In mainstream folklore it is observed that
trying to drink from a firehose can be a good way to rip your lips
off. On computer networks, the absence or failure of flow control
mechanisms can lead to situations in which the sending system
sprays a massive flood of packets at an unfortunate receiving
system; more than it can handle. Compare {overrun}, {buffer
overflow}.
:firewall code: n. The code you put in a system (say, a telephone
switch) to make sure that the users can't do any damage. Since
users always want to be able to do everything but never want to
suffer for any mistakes, the construction of a firewall is a
question not only of defensive coding but also of interface
presentation, so that users don't even get curious about those
corners of a system where they can burn themselves.