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PD
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PDL
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PC-ism
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PD/P-D/ adj.
[common] Abbreviation for `public domain', applied to software distributed overUsenetand 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 cansnarfa copy. Seecopyleft.
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PDL
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PDP-10
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PDL/P-D-L/, /pid'l/, /p*d'l/ or /puhd'l/
1. n. `Program Design Language'. Any of a large class of formal and profoundly useless pseudo-languages in whichmanagementforces one to design programs. Too often, management expects PDL descriptions to be maintained in parallel with the code, imposing massive overhead to little or no benefit. See alsoflowchart. 2. v. To design using a program design language. "I've been pdling so long my eyes won't focus beyond 2 feet." 3. 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'sPostScriptlanguage, but there are many others, such as Xerox InterPress, etc. 4. In ITS days, the preferred MITism forstack. Seeoverflow pdl. 5. Dave Lebling, one of the co-authors ofZork; (hisnetwork addresson the ITS machines was at one time pdl@dms).
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PDP-10
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PDP-20
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PDP-10n.
[Programmed Data Processor model 10] 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) whenDECrecognized 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; seeFoonlyandMars.) This event spelled the doom ofITSand 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. SeeTOPS-10,ITS,BLT,DDT,DPB,EXCH,HAKMEM,LDB,pop,push. See also http://www.inwap.com/pdp10/.
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PDP-20
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PEBKAC
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PDP-20n.
The most famous computer that never was.PDP-10computers running theTOPS-10operating system were labeled `DECsystem-10' as a way of differentiating them from the PDP-11. Later on, those systems runningTOPS-20were labeled `DECSYSTEM-20' (the block capitals being the result of a lawsuit brought against DEC by Singer, which once made a computer called `system-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 painted `Basil Blue', whereas most TOPS-20 machines were painted `Chinese Red' (often mistakenly called orange).
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PEBKAC
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peek
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PDP-20
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PEBKAC/peb'kak/
[Abbrev., "Problem Exists Between Keyboard And Chair"] Used by support people, particularly at call centers and help desks. Not used with the public. Denotes pilot error as the cause of the crash, especially stupid errors that even alusercould figure out. Very derogatory. Usage: "Did you ever figure out why that guy couldn't print?" "Yeah, he kept cancelling the operation before it could finish. PEBKAC."
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peek
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PEBKAC
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peekn.,vt.
(andpoke) The commands in most microcomputer BASICs for directly accessing memory contents at an absolute address; often extended to mean the corresponding constructs in anyHLL(peek reads memory, poke modifies it). Much hacking on small, non-MMU micros used to consist 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 circulated (seeinterrupt list). The results of `poke's at these addresses may be highly useful, mildly amusing, useless but neat, or (most likely) totallossage(seekiller poke).
Since areal operating systemprovides 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 thenewbie. (Of course, OS kernels often have to do exactly this; a real kernel hacker would unhesitatingly, if unportably, assign an absolute address to a pointer variable and indirect through it.)
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pencil and paper
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Pentagram Pro
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pencil and papern.
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-called `handwriting' 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.
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Pentagram Pro
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Pentium
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Pentagram Pron.
A humorous corruption of "Pentium Pro", with a Satanic reference, implying that the chip is inherentlyevil. Often used with "666 MHz"; there is a T-shirt. SeePentium
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Pentium
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peon
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Pentiumn.
The name given to Intel's P5 chip, the successor to the 80486. The name was chosen because of difficulties Intel had in trademarking a number. It suggests the number five (implying 586) while (according to Intel) conveying a meaning of strength "like titanium". Among hackers, the plural is frequently `pentia'. See alsoPentagram Pro.
Intel did not stick to this convention when naming its P6 processor the Pentium Pro; many believe this is due to difficulties in selling a chip with "sex" in its name. Successor chips have been called `Pentium II' and `Pentium III'.
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peon
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percent-S
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Pentium
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peonn.
A person with no special (rootorwheel) privileges on a computer system. "I can't create an account onfoovaxfor you; I'm only a peon there."
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percent-S
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perf
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peon
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percent-S/per-sent' es'/ n.
[From the code in C'sprintf(3)library function used to insert an arbitrary string argument] An unspecified person or object. "I was just talking to some percent-s in administration." Comparerandom.
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perf
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perfect programmer syndrome
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percent-S
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perf/perf/ n.
Syn.chad(sense 1). The term `perfory' /per'f*-ree/ is also heard. The termperfmay also refer to the perforations themselves, rather than the chad they produce when torn (philatelists use it this way).
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perfect programmer syndrome
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Perl
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perf
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perfect programmer syndromen.
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 solvingtoy problems). "Of course my program is correct, there is no need to test it." "Yes, I can see there may be a problem here, butI'llnever typerm -r /while inroot mode."
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Perl
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person of no account
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Perl/perl/ n.
[Practical Extraction and Report Language, a.k.a. Pathologically Eclectic Rubbish Lister] An interpreted language developed by Larry Wall (author ofpatch(1)andrn(1)) and distributed over Usenet. Superficially resemblesawk, but is much hairier, including many facilities reminiscent ofsed(1)and shells and a comprehensive Unix system-call interface. Unix sysadmins, who are almost always incorrigible hackers, generally consider it one of thelanguages of choice, and it is by far the most widely used tool for making `live' web pages via CGI. Perl has been described, in a parody of a famous remark aboutlex(1), as the "Swiss-Army chainsaw" of Unix programming. Though Perl is very useful, it would be a stretch to describe it as pretty orelegant; people who like clean, spare design generally preferPython. See alsoCamel Book,TMTOWTDI.
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person of no account
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pessimal
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Perl
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person of no accountn.
[University of California at Santa Cruz] Used when referring to a person with nonetwork address, frequently to forestall confusion. Most often as part of an introduction: "This is Bill, a person of no account, but he used to be bill@random.com". Comparereturn from the dead.
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pessimal
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pessimal/pes'im-l/ adj.
[Latin-based antonym for `optimal'] 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' and `optimize', but for some reason they do not appear in most English dictionaries, although `pessimize' is listed in the OED.
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pessimizing compiler
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pessimizing compiler/pes'*-mi:z`ing k*m-pi:l'r/ n.
A compiler that produces object [antonym of techspeak `optimizing compiler'] 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.
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peta-
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peta-/pe't*/ pref
[SI] Seequantifiers.
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PETSCII
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PFY
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peta-
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PETSCII/pet'skee/ n. obs.
[abbreviation of PET ASCII] The variation (many would say perversion) of theASCIIcharacter set used by the Commodore Business Machines PET series of personal computers and the later Commodore C64, C16, C128, and VIC20 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.
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PFY
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phage
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PETSCII
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PFYn.
[Usenet; common] Abbreviation for `Pimply-Faced Youth'. ABOFHin training, esp. one apprenticed to an elder BOFH aged in evil.
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phage
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phase
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phagen.
A program that modifies other programs or databases in unauthorized ways; esp. one that propagates avirusorTrojan horse. See alsoworm,mockingbird. The analogy, of course, is with phage viruses in biology.
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phase
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phage
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phase
1. n. The offset of one's waking-sleeping schedule with respect to the standard 24-hour cycle; 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 8P.M.lately, but I'm going towrap aroundto 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 called `changing phase'; `phase shifting' has also been recently reported from Caltech. 2. `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 isshorteningyour day or night that is really hard (seewrap 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.
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phase of the moon
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phase-wrapping
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phase
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phase of the moonn.
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 depends on having the channel open in mumble mode, having the foo switch set, and on the phase of the moon." See alsoheisenbug.
True story: Once upon a time there was a program bug that really did depend on the phase of the moon. There was a little subroutine that had traditionally been used in various programs at MIT to calculate an approximation to the moon's true phase. GLS incorporated this routine into a LISP program that, when it wrote out a file, would print a timestamp line almost 80 characters long. Very occasionally the first line of the message would be too long and would overflow onto the next line, and when the file was later read back in the program wouldbarf. The length of the first line depended on both the precise date and time and the length of the phase specification when the timestamp was printed, and so the bug literally depended on the phase of the moon!
The first paper edition of the Jargon File (Steele-1983) included an example of one of the timestamp lines that exhibited this bug, but the typesetter `corrected' it. This has since been described as the phase-of-the-moon-bug bug.
However, beware of assumptions. A few years ago, engineers of CERN (European Center for Nuclear Research) were baffled by some errors in experiments conducted with the LEP particle accelerator. As the formidable amount of data generated by such devices is heavily processed by computers before being seen by humans, many people suggested the software was somehow sensitive to the phase of the moon. A few desperate engineers discovered the truth; the error turned out to be the result of a tiny change in the geometry of the 27km circumference ring, physically caused by the deformation of the Earth by the passage of the Moon! This story has entered physics folklore as a Newtonian vengeance on particle physics and as an example of the relevance of the simplest and oldest physical laws to the most modern science.
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phase-wrapping
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PHB
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phase of the moon
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phase-wrappingn.
[MIT] Syn.wrap around, sense 2.