:power cycle: /vt./ (also, `cycle power' or just `cycle') To power off a machine and then power it on immediately, with the intention of clearing some kind of {hung} or {gronk}ed state. Syn. {120 reset}; see also {Big Red Switch}. Compare {Vulcan nerve pinch}, {bounce} (sense 4), and {boot}, and see the "{AI Koans}" (in Appendix A) about Tom Knight and the novice.
:power hit: /n./ A spike or drop-out in the electricity supplying your machine; a power {glitch}. These can cause crashes and even permanent damage to your machine(s).
:PPN: /P-P-N/, /pip'n/ /n. obs./ [from `Project-Programmer Number'] A user-ID under {{TOPS-10}} and its various mutant progeny at SAIL, BBN, CompuServe, and elsewhere. Old-time hackers from the PDP-10 era sometimes use this to refer to user IDs on other systems as well.
:precedence lossage: /pre's*-dens los'*j/ /n./ [C programmers] Coding error in an expression due to unexpected grouping of arithmetic or logical operators by the compiler. Used esp. of certain common coding errors in C due to the nonintuitively low precedence levels of `&', `|', `^', `<<', and `>>' (for this reason, experienced C programmers deliberately forget the language's {baroque} precedence hierarchy and parenthesize defensively). Can always be avoided by suitable use of parentheses. {LISP} fans enjoy pointing out that this can't happen in *their* favorite language, which eschews precedence entirely, requiring one to use explicit parentheses everywhere. See {aliasing bug}, {memory leak}, {memory smash}, {smash the stack}, {fandango on core}, {overrun screw}.
:prepend: /pree`pend'/ /vt./ [by analogy with `append'] To prefix. As with `append' (but not `prefix' or `suffix' as a verb), the direct object is always the thing being added and not the original word (or character string, or whatever). "If you prepend a semicolon to the line, the translation routine will pass it through unaltered."
:prestidigitization: /pres`t*-di`j*-ti:-zay'sh*n/ /n./ 1. The act of putting something into digital notation via sleight of hand. 2. Data entry through legerdemain.
:pretty pictures: /n./ [scientific computation] The next step up from {numbers}. Interesting graphical output from a program that may not have any sensible relationship to the system the program is intended to model. Good for showing to {management}.
:prettyprint: /prit'ee-print/ /v./ (alt. `pretty-print') 1. To generate `pretty' human-readable output from a {hairy} internal representation; esp. used for the process of {grind}ing (sense 1) program code, and most esp. for LISP code. 2. To format in some particularly slick and nontrivial way.
:pretzel key: /n./ [Mac users] See {feature key}.
:priesthood: /n. obs./ [TMRC] The select group of system
managers responsible for the operation and maintenance of a batch
operated computer system. On these computers, a user never had
direct access to a computer, but had to submit his/her data and
programs to a priest for execution. Results were returned days or
even weeks later. See {acolyte}.