The Hacker's Dictionary by - (sneezy the snowman read aloud txt) 📕

direct diddling of screen memory, or using hard timing loops.

Compare {ill-behaved}, {vaxism}, {unixism}. Also, `PC-ware' n., a program full of PC-isms on a machine with a more capable operating system. Pejorative.

:PD: /P-D/ adj. Common abbreviation for `public domain', applied to software distributed over {USENET} and from Internet archive sites. Much of this software is not in fact public domain in the legal sense but travels under various copyrights granting reproduction and use rights to anyone who can {snarf} a copy. See {copyleft}.

:pdl: /pid'l/ or /puhd'l/ [abbreviation for `Push Down List']

n. In ITS days, the preferred MITism for {stack}. See {overflow pdl}. 2. n. Dave Lebling, one of the co-authors of {Zork}; (his {network address} on the ITS machines was at one time pdl@dms). 3. n. `Program Design Language'. Any of a large class of formal and profoundly useless pseudo-languages in which {management} forces one to design programs. {Management}

often expects it to be maintained in parallel with the code. See also {{flowchart}}. 4. v. To design using a program design language. "I've been pdling so long my eyes won't focus beyond 2

feet." 5. n. `Page Description Language'. Refers to any language which is used to control a graphics device, usually a laserprinter.

The most common example, is of course, Adobe's {PostScript}

language, but there are many others, such as Xerox InterPress, etc.

:PDP-10: [Programmed Data Processor model 10] n. The machine that made timesharing real. It looms large in hacker folklore because of its adoption in the mid-1970s by many university computing facilities and research labs, including the MIT AI Lab, Stanford, and CMU. Some aspects of the instruction set (most notably the bit-field instructions) are still considered unsurpassed. The 10

was eventually eclipsed by the VAX machines (descendants of the PDP-11) when DEC recognized that the 10 and VAX product lines were competing with each other and decided to concentrate its software development effort on the more profitable VAX. The machine was finally dropped from DEC's line in 1983, following the failure of the Jupiter Project at DEC to build a viable new model. (Some attempts by other companies to market clones came to nothing; see {Foonly}) This event spelled the doom of {{ITS}} and the technical cultures that had spawned the original Jargon File, but by mid-1991 it had become something of a badge of honorable old-timerhood among hackers to have cut one's teeth on a PDP-10.

See {{TOPS-10}}, {{ITS}}, {AOS}, {BLT}, {DDT}, {DPB}, {EXCH}, {HAKMEM}, {JFCL}, {LDB}, {pop}, {push}, {appendix A}.

:PDP-20: n. The most famous computer that never was. {PDP-10}

computers running the {{TOPS-10}} operating system were labeled `DECsystem-10' as a way of differentiating them from the PDP-11.

Later on, those systems running {TOPS-20} were labeled DECSYSTEM-20' (the block capitals being the result of a lawsuit brought against DEC by Singer, which once made a computer calledsystem-10'), but contrary to popular lore there was never a PDP-20'; the only difference between a 10 and a 20 was the operating system and the color of the paint. Most (but not all) machines sold to run TOPS-10 were paintedBasil Blue', whereas most TOPS-20 machines were painted `Chinese Red' (often mistakenly called orange).

:peek: n.,vt. (and {poke}) The commands in most microcomputer BASICs for directly accessing memory contents at an absolute address; often extended to mean the corresponding constructs in any {HLL} (peek reads memory, poke modifies it). Much hacking on small, non-MMU micros consists of peek'ing around memory, more or less at random, to find the location where the system keeps interesting stuff. Long (and variably accurate) lists of such addresses for various computers circulate (see {{interrupt list, the}}). The results ofpoke's at these addresses may be highly useful, mildly amusing, useless but neat, or (most likely) total {lossage} (see {killer poke}).

Since a {real operating system} provides useful, higher-level services for the tasks commonly performed with peeks and pokes on micros, and real languages tend not to encourage low-level memory groveling, a question like "How do I do a peek in C?" is diagnostic of the {newbie}. (Of course, OS kernels often have to do exactly this; a real C hacker would unhesitatingly, if unportably, assign an absolute address to a pointer variable and indirect through it.)

:pencil and paper: n. An archaic information storage and transmission device that works by depositing smears of graphite on bleached wood pulp. More recent developments in paper-based technology include improved write-once' update devices which use tiny rolling heads similar to mouse balls to deposit colored pigment. All these devices require an operator skilled at so-calledhandwriting' technique. These technologies are ubiquitous outside hackerdom, but nearly forgotten inside it. Most hackers had terrible handwriting to begin with, and years of keyboarding tend to have encouraged it to degrade further. Perhaps for this reason, hackers deprecate pencil-and-paper technology and often resist using it in any but the most trivial contexts. See also {appendix B}.

:peon: n. A person with no special ({root} or {wheel}) privileges on a computer system. "I can't create an account on foovax for you; I'm only a peon there."

:percent-S: /per-sent' es'/ [From the code in C's `printf(3)'

library function used to insert an arbitrary string argument] n. An unspecified person or object. "I was just talking to some percent-s in administration." Compare {random}.

:perf: /perf/ n. See {chad} (sense 1). The term `perfory'

/per'f*-ree/ is also heard. The term {perf} may also refer to the preforations themselves, rather than the chad they produce when torn.

:perfect programmer syndrome: n. Arrogance; the egotistical conviction that one is above normal human error. Most frequently found among programmers of some native ability but relatively little experience (especially new graduates; their perceptions may be distorted by a history of excellent performance at solving {toy problem}s). "Of course my program is correct, there is no need to test it." "Yes, I can see there may be a problem here, but I'll never type `rm -r /' while in {root}."

:Perl: /perl/ [Practical Extraction and Report Language, a.k.a Pathologically Eclectic Rubbish Lister] n. An interpreted language developed by Larry Wall [email protected], author of patch(1)' andrn(1)') and distributed over USENET.

Superficially resembles awk(1)', but is much hairier (see {awk}). UNIX sysadmins, who are almost always incorrigible hackers, increasingly consider it one of the {languages of choice}. Perl has been described, in a parody of a famous remark aboutlex(1)', as the "Swiss-Army chainsaw" of UNIX

programming.

:pessimal: /pes'im-l/ [Latin-based antonym for `optimal'] adj.

Maximally bad. "This is a pessimal situation." Also `pessimize'

vt. To make as bad as possible. These words are the obvious Latin-based antonyms for optimal' andoptimize', but for some reason they do not appear in most English dictionaries, although `pessimize' is listed in the OED.

:pessimizing compiler: /pes'*-mi:zing k*m-pi:l'r/ [antonym ofoptimizing compiler'] n. A compiler that produces object code that is worse than the straightforward or obvious hand translation. The implication is that the compiler is actually trying to optimize the program, but through excessive cleverness is doing the opposite. A few pessimizing compilers have been written on purpose, however, as pranks or burlesques.

:peta-: /pe't*/ [SI] pref. See {{quantifiers}}.

:PETSCII: /pet'skee/ [abbreviation of PET ASCII] n. The variation (many would say perversion) of the {{ASCII}} character set used by the Commodore Business Machines PET series of personal computers and the later Commodore C64, C16, and C128 machines. The PETSCII set used left-arrow and up-arrow (as in old-style ASCII) instead of underscore and caret, placed the unshifted alphabet at positions 65--90, put the shifted alphabet at positions 193--218, and added graphics characters.

:phase: 1. n. The phase of one's waking-sleeping schedule with respect to the standard 24-hour cycle. This is a useful concept among people who often work at night and/or according to no fixed schedule. It is not uncommon to change one's phase by as much as 6

hours per day on a regular basis. "What's your phase?" "I've been getting in about 8 P.M. lately, but I'm going to {wrap around} to the day schedule by Friday." A person who is roughly 12 hours out of phase is sometimes said to be in `night mode'.

(The term day mode' is also (but less frequently) used, meaning you're working 9 to 5 (or, more likely, 10 to 6).) The act of altering one's cycle is calledchanging phase'; `phase shifting' has also been recently reported from Caltech.

change phase the hard way': To stay awake for a very long time in order to get into a different phase. 3.change phase the easy way': To stay asleep, etc. However, some claim that either staying awake longer or sleeping longer is easy, and that it is shortening your day or night that's hard (see {wrap around}). The `jet lag' that afflicts travelers who cross many time-zone boundaries may be attributed to two distinct causes: the strain of travel per se, and the strain of changing phase. Hackers who suddenly find that they must change phase drastically in a short period of time, particularly the hard way, experience something very like jet lag without traveling.

:phase of the moon: n. Used humorously as a random parameter on which something is said to depend. Sometimes implies unreliability of whatever is dependent, or that reliability seems to be dependent on conditions nobody has been able to determine. "This feature