Hack mode : n. What one is in when hacking, of course. 2. More specifically, a Zen-like state of total focus on The Problem that may be achieved when one is hacking (this is why every good hacker is part mystic). Ability to enter such concentration at will correlates strongly with wizardliness; it is one of the most important skills learned during {larval stage}. Sometimes amplified as `deep hack mode'. Being yanked out of hack mode (see {priority interrupt}) may be experienced as a physical shock, and the sensation of being in hack mode ismore than a little habituating. The intensity of this experience is probably by itself sufficient explanation for the existence of hackers, and explains why many resist being promoted out of positions where they can code. See also {cyberspace} (sense 2). Some aspects of hackish etiquette will appear quite odd to an observer unaware of the high value placed on hack mode. For example, if someone appears at your door, it is perfectly okay to hold up a hand (without turning one's eyes away from the screen) to avoid being interrupted. One may read, type, and interact with the computer for quite some time before further acknowledging the other's presence (of course, he or she is reciprocally free to leave without a word). The understanding is that you might be in {hack mode} with a lot of delicate {state} (sense 2) in your head, and you dare not {swap} that context out until you have reached a good point to pause. See also {juggling eggs}.:hack value: n. Often adduced as the reason or motivation for expending effort toward a seemingly useless goal, the point being that the accomplished goal is a hack. For example, MacLISP had features for reading and printing Roman numerals, which were installed purely for hack value. See {display hack} for one method of computing hack value, but this cannot really be explained, only experienced. As Louis Armstrong once said when asked to explain jazz: "Man, if you gotta ask you'll never know." (Feminists please note Fats Waller's explanation of rhythm: "Lady, if you got to ask you ain't got it.")