package --
A unit of application software. In addition to the application itself,
a package can also contain related files, such as configuration files,
device files, or data files.
packet --
A logical group of data that is sent over a network. Sometimes called a
``data packet''. One or more packets comprise a
datagram.
packet switching --
A concept which states that a network transmits packets
over connections that last only for the duration of
the transmission.
packet structure --
The characteristics that define a packet. The structure defines the
size of each area of the packet and what each of those pieces
of information is for.
page --
A fixed length, 4096-byte block that has a virtual address,
and that can be transferred between main and secondary storage.
paging --
A memory-management technique in which programs are
organized into pages that can be transferred
between main and secondary storage by the virtual handler (or paging
daemon).
pan --
To change the view area.
pane --
(programming)
The rectangular area within a window where an application displays
text or graphics.
panic --
(programming)
The state where an unrecoverable error has occurred.
Usually, when a panic occurs, a message is displayed
on the console to indicate the cause of the problem.
parallel port --
A physical connector on the computer that can be used to establish links to
a parallel device, such as a printer.
parallel printer --
Any printer directly connected to a parallel port (for example, LPT1 or LPT2)
on your computer.
parameter --
An entity associated with a value. For example, if a command
requires a given parameter, the command must be invoked with a
value provided for that parameter. The various options specified
after a command's name on the shell command line are the
command's parameters. They can be referred to as
positional parameters if they are identified by their
numerical position on the command line.
See also
argument
and
option.
parent directory icon --
An icon that moves you up one directory in the filesystem
hierarchy when you double-click on it.
parent process --
See
fork .
parity --
A bit added to character bits to make the total number of bits odd or even. The
system uses parity bits for error checking. UNIX systems use a 7-bit even
parity.
parser --
(programming)
A parser, also known as a syntactic analyzer, analyzes the grammatical
form of tokens passed to it by a lexical analyzer.
See
lexical analysis.
partition --
A portion of the hard disk that is separated from other areas of the
hard disk. Different operating systems must be on different partitions.
password --
The string of characters you are prompted for after you type your
login name
when you are logging in. Your password is the key that
lets you into the UNIX system; you should choose it
wisely, keep it secret, and change it regularly. Use the
passwd(1)
command to change your password.
paste --
To insert previously cut or copied text from the clipboard
into a file or a window.
path --
The
directory
list through which your
shell
searches to find the commands you type. Your path is
stored in the
shell variable
PATH.
pathname --
The name of a
directory
or a
file,
for example, /usr/spool/mail. Each component of
a pathname, as separated by slashes, is a directory, except
for the last component of a pathname, which can be either a
directory or a file. A single word by itself, such as
Tutorial, can be a pathname; this is a
relative pathname
for the file or directory Tutorial
from the
current working directory.
A single slash, (/), is the pathname for the
root
directory.
See also
absolute pathname
and
relative pathname.
pattern --
A string containing a regular expression. The pattern is said to
match a string of literal characters if there exists a
correspondence between the in-order elements of the string and
the permitted values of the expression elements in the pattern.
pattern match --
To find strings of characters in a text file that match
a string you specify.
pattern space --
An area of memory used by the
sed(1)
stream editor to store the current line (or lines)
of the file being processed.
portable device interface (PDI) --
A collection of driver routines, kernel functions, and data structures that
provide a standard interface for writing block drivers.
PDU --
Protocol Data Unit. A data object exchanged by protocol machines
(such as management stations, SMUX peers, and SNMP
agents) and consisting of both protocol control information and user data.
PDU is sometimes used as a synonym for
packet.
peer --
For SNMP, software running on a network device, which manages a
specific
MIB module.
A
peer
receives requests from, and issues
responses to, an SNMP
agent
via the SMUX protocol.
peer user --
(programming)
The user with whom a given user
is communicating above the Transport Interface.
permissions --
The settings (also called properties or attributes)
associated with each file or directory that
determine who can access or modify the file and directory.
Use the
ls(1)
command with a -l option to list a file's permissions;
use the
chmod(1)
(change mode) command to change a file's permissions.
physical block --
A unit of data as actually stored and
manipulated.
ping --
1. Used to test and time network communications.
See
ping(1Mtcp).
2. (programming)
A call to procedure 0 of an RPC program.
Pinging is used to verify the existence and
accessibility of a remote program.
pinned menu --
(programming)
A menu that has a pushpin that is ``in.''
This menu behaves much like a control area in a pinned
command window.
pipe --
A way of joining commands on the command line so that the
output of one command provides the input for the next. To
use a pipe on the command line, join commands with the vertical bar
symbol (|). For example, to sort a
file, eliminate duplicate lines, and print it, you could
type sort file | uniq | lp.
pixmap --
1. A picture or other graphical image that can include
multiple colors.
2. (programming) A bitmap of an area of the screen stored
within the program. A pixmap is also a defined data type
in the Xt Intrinsics.
pixel --
(programming)
An addressable point on the screen.
plain file --
A file containing text or data that is not executable.
See also
executable file.
point --
To position the pointer.
point-and-pick --
A method of selecting a command or file to edit by
using the arrow keys to highlight one or more selections on
a list. See also
scroll bars.
pointer --
See
mouse pointer.
poll --
The sending of an NTP packet from a host to an
NTP time server to request the current time. The
server responds by recording the current time in the
packet, then sending it back to the originating host. See
also
NTP packet.
polling --
The interrogation of devices by the operating system
to avoid contention, determine operation status, or ascertain
readiness to send or receive data.
pop up --
As a noun, pop up is a generic term
referring to a window other than the base window.
As a verb, this phrase is the act of
making a menu or popup window visible.
As an adjective, it is used to refer to a window
that can be popped up and is
spelled without a dash,
as in popup menu.
popup window --
A window that is displayed on top of the active window.
Popup windows display choices, prompt for user input,
or display informative text.
portability --
Portability refers to the degree of ease with which a program
can be moved (or ported) to a different operating system or machine.
port numbers --
Numbers used by
UDP
and
TCP
to identify the end points of communication.
ports --
The point of physical connection between a peripheral device
(such as a terminal or a printer) and the device controller
(ports board), which is part of the computer hardware.
positional parameter --
(programming) When a program is executed on the command line, its parameters
can be accessed from inside the program by referring to
their numerical position on the command line. Positional
parameters are referred to within a shell script by the
variables $1, $2 ... $n, from
left to right along the line. $0 is the name of
the program itself.
post --
(programming)
The FMLI activity of reading and
interpreting a frame definition file,
displaying the frame described therein,
and making that frame current.
postmaster --
An address that is required for every domain
on the Internet by RFC 821/822. People send
inquiries about user and host names to the
postmaster address in that domain.
PostScript --
PostScript®, developed by Adobe® Systems, Inc, is a
programming language describing how to print a page that contains
both text and graphic elements. A PostScript file is a file containing a
PostScript printer control program. Usually, a PostScript
file can be printed by sending it to a PostScript printer.
PPP --
Point-to-Point Protocol,
the Internet data-link protocol for carrying multi-protocol datagrams
(including IP datagrams) over serial links.
See also
datagram.
preferred block size --
(programming)
The unit of transfer for block devices in read/write operations
(also known as ``logical block size'').
prefix --
(programming)
A character name that
uniquely identifies a driver's routines to the
kernel.
The prefix name starts each routine in a
driver.
For example,
a RAM disk might be given the ramd prefix.
If it is a
block driver,
the routines are
ramdopen, ramdclose,
ramdstrategy, and ramdprint.
preprocessor --
(programming)
A preprocessor is a program that prepares
an input file for another program.
The preprocessor component of the C compiler
performs macro expansion, conditional compilation, and file inclusion.
primary server --
Another name for a stratum 1 server. See also
stratum.
primary source window --
(programming)
When using the GUI debugger,
the primary source window is
displayed when you select
the Source Window button in the Windows menu.
The primary window is always updated to show the current
source line whenever the current process stops.
primitive --
An operation that results from the
decomposition of a remote administrative task
for execution over a network service;
examples include file transfer,
directory transfer, and remote execution.
primitive widget --
(programming)
A widget that does not have any child widgets; one that
either performs a specific action, allows input, or allows output.
See also
widget.
print job --
A request you have made to the printer to print a
file.
Each print job has an ID number that you can see
using the
lpstat(1)
command. You can cancel a print job by typing
cancel and its job ID number, then
pressing <Enter> (see the
lpstat(1)
manual page for further information about the
cancel command).
print queue --
A queue (line) in which print requests
are stored while they are waiting to be printed.
print spooler --
A program that manages print requests.
priority --
A
peer
registration request parameter which allows an
SNMP
agent
to resolve conflicting registration
attempts. All peer registration requests have an associated priority,
which has an integer value in the range 0 (indicating highest possible
priority) to (2[31] - 1). Many peers may register the same
MIB module,
but they must do so at different priorities.
The peer with the highest registration priority
for a given MIB module is consulted exclusively for
all operations on objects in that module.
priority message --
(programming)
STREAMS messages that must move through the stream quickly are
classified as priority messages. They are placed at the head of the
queue for processing by the
srv(D2str)
routine.
privilege --
The ability to override system restrictions and thus access
or use a system call, function, resource, or program.
See also
process privilege.
privileged process --
A process that has at least one of the process privileges.
See also
process privilege.
process --
A single instance of a program in execution. This can be a
login shell or an operating system command, but not a built-in
shell command. If a command is built into the shell, a
separate process is not created on its invocation; the
built-in command is issued within the context of the shell
process.
Processes differ from programs in that they are actively present in memory, and their state changes with time. A program, on the other hand, does nothing until it is execed and gives rise to a process. Each process is assigned a unique numerical ID. See also process ID.
process ID --
A number that uniquely identifies a running program on the
UNIX system.
This is also known as the PID.
processor --
The main processing unit of the computer that controls the processing routines,
performs the arithmetic functions, and maintains accessible memory.
Frequently referred to as the Central Processing Unit (CPU).
process privilege --
Authorization for a process to perform sensitive operations.
profile --
A file containing shell commands which are executed when a
login shell starts up.
program --
1. Software that performs a task.
Desktop controls, accessories, and applications are all
programs.
2. A set of instructions and data kept in an ordinary file.
prompt --
One or more characters or symbols that identify a line
on which commands can be entered.
``Prompt'' also refers to the text displayed when
the computer displays a request for input or an
instruction.
The default prompt can be replaced by setting the PS1
environment variable.
protocol --
A formal description of message formats and the rules that
two or more machines must follow to exchange messages.
pseudo-device --
A special object in the system used to perform special-purpose
system functions. Examples of pseudo-devices are memory
pseudo-devices and pseudo-terminals.
Pseudo-devices have associated
Device Special File (DSF)s
and the same access semantics as physical devices, but
they might not have associated device hardware.
pseudo terminal --
The software implementation of a terminal, used as an active agent in
communicating between processes and users. For example, a remote login
server uses pseudo-terminals for remote login sessions.
See also
pseudo-device.
public key cryptography --
A cipher system that uses a published public key
and an encoded secret key.
pull-down menu --
A menu that can be pulled down from the menu bar by
clicking on its name.
push button --
A graphical representation on the screen of a real-life
push button.
You can position the mouse pointer on an onscreen button
and click to ``push'' the onscreen button, thus initiating
the corresponding action.
pushpin --
(programming)
A screen object that is part of a popup menu.
It can be pointed to and selected.
When it is first selected, it is ``pushed in'' and causes
the menu to stay up after
the user moves out of it.
When it is again selected, it is pulled out and the
menu pops down.