1. PUBlishing. A 1972 text-formatting language for TOPS-10, with syntax based on
SAIL. Influenced TeX and Scribe. ["PUB: The Document Compiler", Larry Tesler,
Stanford AI Proj Op Note, Sept 1972].
2. /pub, the top-level, publicly accessible directory on most anonymous FTP
archives. This is usually where the interesting files are. See pubic directory.
PTN « Ptolemy « PTT « PUB » pubic directory »
public domain » public domain software
[NYU] (also "pube directory" /pyoob' d*-rek't*-ree/) The "pub" (public)
directory on a machine that allows FTP access. So called because it is the
default location for SEX (software exchange).
Ptolemy « PTT « PUB « pubic directory »
public domain » public domain software » public-key
(PD) The total absence of copyright protection. If something is "in the public
domain" then anyone can copy it or use it in any way they wish. The author has
none of the exclusive rights which apply to a copyright work.
The phrase "public domain" is often used incorrectly to refer to freeware or
shareware (software which is copyrighted but is distributed without (advance)
payment). Public domain means no copyright -- no exclusive rights. In fact the
phrase "public domain" has no legal status at all in the UK.
See also archive site, careware, charityware, copyleft, crippleware, guiltware,
postcardware and -ware. Compare payware.
PTT « PUB « pubic directory « public domain »
public domain software » public-key cryptography »
Public-Key Cryptography Standards
public domain software
PUB « pubic directory « public domain « public
domain software » public-key cryptography »
Public-Key Cryptography Standards » public-key
pubic directory « public domain « public domain
public-key cryptography » Public-Key
Cryptography Standards » public-key encryption »
Public Key Infrastructure
Public-Key Cryptography Standards
<cryptography, standard> (PKCS) A set of standards for public-key
cryptography, developed by RSA Data Security, Inc. in cooperation with an
informal consortium, originally including Apple, Microsoft, DEC, Lotus, Sun and
MIT. The PKCS have been cited by the OSI Implementers' Workshop (OIW) as a
method for implementation of OSI standards.
PKCS includes both algorithm-specific and algorithm-independent implementation
standards. Many algorithms are supported, including RSA and Diffie-Hellman key
exchange, however, only the latter two are specifically detailed. PKCS also
defines an algorithm-independent syntax for digital signatures, digital
envelopes, and extended digital certificates; this enables someone implementing
any cryptographic algorithm whatsoever to conform to a standard syntax, and thus
public domain « public domain software « public-key
cryptography « Public-Key Cryptography Standards
» public-key encryption » Public Key Infrastructure
» Public Switched Telephone Network
<cryptography> (PKE, Or "public-key cryptography") An encryption scheme,
introduced by Diffie and Hellman in 1976, where each person gets a pair of keys,
called the public key and the private key. Each person's public key is published
while the private key is kept secret. Messages are encrypted using the intended
recipient's public key and can only be decrypted using his private key. This is
often used in conjunction with a digital signature.
The need for sender and receiver to share secret information (keys) via some
secure channel is eliminated: all communications involve only public keys, and
no private key is ever transmitted or shared.
Public-key encryption can be used for authentication, confidentiality, integrity
RSA encryption is an example of a public-key cryptosystem.
See also knapsack problem.
public domain software « public-key cryptography «
Public-Key Cryptography Standards « public-key
» Public Key Infrastructure » Public Switched
Telephone Network » puff
Public Key Infrastructure
<cryptography, communications> (PKI) A system of public key encryption
using digital certificates from Certificate Authorities and other registration
authorities that verify and authenticate the validity of each party involved in
an electronic transaction.
PKIs are currently evolving and there is no single PKI nor even a single
agreed-upon standard for setting up a PKI. However, nearly everyone agrees that
reliable PKIs are necessary before electronic commerce can become widespread.
US DOD PKI.
US NIST PKI.
IETF PKIX Working Group.
public-key cryptography « Public-Key Cryptography
Standards « public-key encryption « Public Key
Infrastructure » Public Switched Telephone
Network » puff » PUFFT
Public Switched Telephone Network
<communications> (PSTN, T.70) The collection of interconnected systems
operated by the various telephone companies and administrations (telcos and
PTTs) around the world. Also known as the Plain Old Telephone System (POTS) in
contrast to xDSL and ISDN (not to mention other forms of PANS).
The PSTN started as human-operated analogue circuit switching systems
(plugboards), progressed through electromechanical switches. By now this has
almost completely been made digital, except for the final connection to the
subscriber (the "last mile"): The signal coming out of the phone set is
analogue. It is usually transmitted over a twisted pair cable still as an
analogue signal. At the telco office this analogue signal is usually digitised,
using 8000 samples per second and 8 bits per sample, yielding a 64 kb/s data
stream (DS0). Several such data streams are usually combined into a fatter
stream: in the US 24 channels are combined into a T1, in Europe 31 DS0 channels
are combined into an E1 line. This can later be further combined into larger
chunks for transmission over high-bandwidth core trunks. At the receiving end
the channels are separated, the digital signals are converted back to analogue
and delivered to the received phone.
While all these conversions are inaudible when voice is transmitted over the
phone lines it can make digital communication difficult. Items of interest
include A-law to mu-law conversion (and vice versa) on international calls;
robbed bit signalling in North America (56 kbps <--> 64 kbps); data compression
to save bandwidth on long-haul trunks; signal processing such as echo
suppression and voice signal enhancement such as AT&T TrueVoice.
Public-Key Cryptography Standards « public-key
encryption « Public Key Infrastructure « Public
Switched Telephone Network » puff » PUFFT » pull
<algorithm> To decompress data that has been crunched by Huffman coding.
At least one widely distributed Huffman decoder program was actually *named*
"PUFF", but these days it is usually packaged with the encoder.
public-key encryption « Public Key Infrastructure «
Public Switched Telephone Network « puff »
PUFFT » pull » pull-down list
["The Purdue University Fast Fortran Translator", Saul Rosen et al, CACM
8(11):661-666 (Nov 1965)].
Public Key Infrastructure « Public Switched
Telephone Network « puff « PUFFT » pull »
pull-down list » pull-down menu
Public Switched Telephone Network « puff « PUFFT «
» pull-down list » pull-down menu » pull media
<operating system> (Or "drop-down list") A graphical user interface
component that allows the user to choose one (or sometimes more than one) item
from a list. The current choice is visible in a small rectangle and when the
user clicks on it, a list of items is revealed below it. The user can then click
on one of these to make it the current choice and the list disappears. In some
cases, by holding down a modifier key such as Ctrl when clicking, the selection
is added to (or removed from) the set of current choices rather than replacing
puff « PUFFT « pull « pull-down list »
pull-down menu » pull media » Pulse Code Modulation
<operating system> (Or "drop-down menu", "pop-down menu") A menu in a
graphical user interface, whose title is normally visible but whose contents are
revealed only when the user activates it, normally by pressing the mouse button
while the pointer is over the title, whereupon the menu items appear below the
title. The user may then select an item from the menu or click elsewhere, in
either case the menu contents are hidden again. A menu item is selected either
by dragging the mouse from the menu title to the item and releasing or by
clicking the title and then the item.
When a pull-down menu appears in the main area of a window, as opposed to the
menu bar, it may have a small, downward-pointing triangle to the right.
Compare: scrollable list.
PUFFT « pull « pull-down list « pull-down menu
» pull media » Pulse Code Modulation » pumpkin
<messaging> A model of media distribution were the bits of content have
to be requested by the user, e.g. normal use of HTTP on the World-Wide Web.
Opposite: "push media".
pull « pull-down list « pull-down menu « pull
media » Pulse Code Modulation » pumpkin »
Pulse Code Modulation
<data> (PCM) A method by which an audio signal is represented as digital
Virtually all digital audio systems use PCM, including, CD, DAT, F1 format, 1630
format, DASH, DCC, and MD. Many people get confused because "PCM" is also slang
for Sony's F1 format which stores PCM digital audio on videotape.
pull-down list « pull-down menu « pull media «
Pulse Code Modulation » pumpkin » pumpkineer »
<jargon> A humourous term for the token - the object (notional or real)
that gives its possessor (the "pumpking" or the "pumpkineer") exclusive access
to something, e.g. applying patches to a master copy of source (for which the
pumpkin is called a "patch pumpkin").
Chip Salzenberg <firstname.lastname@example.org> wrote:
David Croy once told me once that at a previous job, there was one tape drive
and multiple systems that used it for backups. But instead of some high-tech
exclusion software, they used a low-tech method to prevent multiple simultaneous
backups: a stuffed pumpkin. No one was allowed to make backups unless they had
the "backup pumpkin".
pull-down menu « pull media « Pulse Code Modulation
pumpkin » pumpkineer » pumpking » punch card
pull media « Pulse Code Modulation « pumpkin «
» pumpking » punch card » punched card
Pulse Code Modulation « pumpkin « pumpkineer «
» punch card » punched card » punt
pumpkin « pumpkineer « pumpking « punch card
» punched card » punt » Purdue Compiler-Construction
<storage, history> (Or "punch card") The signature medium of computing's
Stone Age, now long obsolete outside of a few legacy systems. The punched card
actually predates computers considerably, originating in 1801 as a control
device for Jacquard looms. Charles Babbage used them as a data and program
storage medium for his Analytical Engine:
"To those who are acquainted with the principles of the Jacquard loom, and who
are also familiar with analytical formulę, a general idea of the means by which
the Engine executes its operations may be obtained without much difficulty. In
the Exhibition of 1862 there were many splendid examples of such looms. [...]
These patterns are then sent to a peculiar artist, who, by means of a certain
machine, punches holes in a set of pasteboard cards in such a manner that when
those cards are placed in a Jacquard loom, it will then weave upon its produce
the exact pattern designed by the artist. [...] The analogy of the Analytical
Engine with this well-known process is nearly perfect. There are therefore two
sets of cards, the first to direct the nature of the operations to be performed
-- these are called operation cards: the other to direct the particular
variables on which those cards are required to operate -- these latter are
called variable cards. Now the symbol of each variable or constant, is placed at
the top of a column capable of containing any required number of digits."
-- from Chapter 8 of Charles Babbage's "Passages from the Life of a
The version patented by Herman Hollerith and used with mechanical tabulating
machines in the 1890 US Census was a piece of cardboard about 90 mm by 215 mm.
There is a widespread myth that it was designed to fit in the currency trays
used for that era's larger dollar bills, but recent investigations have
IBM (which originated as a tabulating-machine manufacturer) married the punched
card to computers, encoding binary information as patterns of small rectangular
holes; one character per column, 80 columns per card. Other coding schemes,
sizes of card, and hole shapes were tried at various times.
The 80-column width of most character terminals is a legacy of the IBM punched
card; so is the size of the quick-reference cards distributed with many
varieties of computers even today.
See chad, chad box, eighty-column mind, green card, dusty deck, lace card, card
pumpkineer « pumpking « punch card « punched card
» punt » Purdue Compiler-Construction Tool Set »
(From the punch line of an old joke referring to American football: "Drop back
15 yards and punt!") 1. To give up, typically without any intention of retrying.
"Let's punt the movie tonight." "I was going to hack all night to get this
feature in, but I decided to punt" may mean that you've decided not to stay up
all night, and may also mean you're not ever even going to put in the feature.
2. More specifically, to give up on figuring out what the Right Thing is and
resort to an inefficient hack.
3. A design decision to defer solving a problem, typically because one cannot
define what is desirable sufficiently well to frame an algorithmic solution. "No
way to know what the right form to dump the graph in is - we'll punt that for
4. To hand a tricky implementation problem off to some other section of the
design. "It's too hard to get the compiler to do that; let's punt to the
pumpking « punch card « punched card « punt »
Purdue Compiler-Construction Tool Set » Purdue
University » pure functional language
Purdue Compiler-Construction Tool Set
<tool> (PCCTS) A highly integrated lexical analser generator and parser
generator by Terence J. Parr <email@example.com>, Will E. Cohen and Henry
G. Dietz <firstname.lastname@example.org>, both of Purdue University.
ANTLR (ANother Tool for Language Recognition) corresponds to YACC and DLG
(DFA-based Lexical analyser Generator) functions like LEX. PCCTS has many
additional features which make it easier to use for a wide range of translation
problems. PCCTS grammars contain specifications for lexical and syntactic
analysis with selective backtracking ("infinite lookahead"), semantic
predicates, intermediate-form construction and error reporting. Rules may employ
Extended BNF (EBNF) grammar constructs and may define parameters, return values,
and have local variables.
Languages described in PCCTS are recognised via LLk parsers constructed in pure,
human-readable, C code. Selective backtracking is available to handle non-LL(k)
constructs. PCCTS parsers may be compiled with a C++ compiler. PCCTS also
includes the SORCERER tree parser generator.
Current version: 1.10, runs under Unix, MS-DOS, OS/2, and Macintosh and is very
UK FTP. Macintosh FTP.
Mailing list: email@example.com ("subscribe pccts-users
your_name" in the message body).
E-mail: Terence J. Parr <firstname.lastname@example.org>, Roberto Avanzi
<email@example.com> (Mac port).
punch card « punched card « punt « Purdue
Compiler-Construction Tool Set » Purdue
University » pure functional language » pure
punched card « punt « Purdue Compiler-Construction
Tool Set « Purdue University » pure
functional language » pure lambda-calculus »
pure functional language
purely functional language
punt « Purdue Compiler-Construction Tool Set «
Purdue University « pure functional language
» pure lambda-calculus » PureLink » Pure Lisp
Lambda-calculus with no constants, only functions expressed as lambda
Purdue Compiler-Construction Tool Set « Purdue
University « pure functional language « pure
lambda-calculus » PureLink » Pure Lisp » purely
An incremental linker from Pure Software.
Purdue University « pure functional language « pure
lambda-calculus « PureLink » Pure Lisp »
purely functional language » Purify
A purely functional language derived from Lisp by excluding any feature which
pure functional language « pure lambda-calculus «
Pure Lisp » purely functional language » Purify
» Purple Book
purely functional language
<language> A language that supports only functional programming and does
not allow functions to have side-effects. Program execution consists of
evaluation of an expression and all subexpressions are referentially
pure lambda-calculus « PureLink « Pure Lisp «
purely functional language » Purify » Purple
Book » purple wire
A debugging tool from Pure Software.
PureLink « Pure Lisp « purely functional language «
Purify » Purple Book » purple wire » Purveyor
1. <publication> The "System V Interface Definition". The covers of the
first editions were an amazingly nauseating shade of off-lavender.
2. <publication> The Wizard Book.
See also book titles.
Pure Lisp « purely functional language « Purify «
Purple Book » purple wire » Purveyor » push
<jargon, hardware> Wire installed by IBM Field Engineers to work around
problems discovered during testing or debugging. These are called "purple wires"
even when (as is frequently the case) they are yellow.
Compare blue wire, yellow wire, and red wire.
purely functional language « Purify « Purple Book «
purple wire » Purveyor » push » push-button
<World-Wide Web> A World-Wide Web server for Windows NT and Windows 95
Purify « Purple Book « purple wire « Purveyor
» push » push-button » Push Down List
1. <programming> To put something onto a stack or pdl.
2. <communications> push media.
Purple Book « purple wire « Purveyor « push »
push-button » Push Down List » push media
<electronics> A roughly fingertip-sized plastic cover attached to a
spring-loaded, normally-open switch, which, when pressed, closes the switch.
Typical examples are the keys on a computer or calculator keyboard and mouse
purple wire « Purveyor « push « push-button »
Push Down List » push media » PVC
Push Down List
<programming> (PDL) In ITS days, the preferred MITism for stack.
See overflow pdl.
Purveyor « push « push-button « Push Down List
» push media » PVC » PVM
<messaging> A model of media distribution where items of content are sent
to the user (viewer, listener, etc.) in a sequence, and at a rate, determined by
a server to which the user has connected. This contrasts with pull media where
the user requests each item individually. Push media usually entail some notion
of a "channel" which the user selects and which delivers a particular kind of
Broadcast television is (for the most part) the prototypical example of push
media: you turn on the TV set, select a channel and shows and commercials stream
out until you turn the set off.
By contrast, the World-Wide Web is (mostly) the prototypical example of pull
media: each "page", each bit of content, comes to the user only if he requests
it; put down the keyboard and the mouse, and everything stops.
At the time of writing (April 1997), much effort is being put into blurring the
line between push media and pull media. Most of this is aimed at bringing more
push media to the Internet, mainly as a way to disseminate advertising, since
telling people about products they didn't know they wanted is very difficult in
a strict pull media model.
These emergent forms of push media are generally variations on targeted
advertising mixed in with bits of useful content. "At home on your computer, the
same system will run soothing screensavers underneath regular news flashes, all
while keeping track, in one corner, of press releases from companies whose
stocks you own. With frequent commercial messages, of course." (Wired, March
1997, page 12).
Pointcast is probably the best known push system on the Internet at the
time of writing.
As part of the eternal desire to apply a fun new words to boring old things,
"push" is occasionally used to mean nothing more than email spam.
push « push-button « Push Down List « push media
» PVC » PVM » PV-WAVE