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pacing. (1.) A technique used by a receiving component to control the rate of transmission by sending a component to prevent overrun. (2.) A file transfer protocol required by some systems. It controls data transmission by waiting for a specified character, or waiting a specified number of seconds between lines. This protocol prevents the loss of data when the block size is too large or data is sent too quickly for the system to process. See also line pacing, local pacing, receive pacing, and remote pacing.

pacing response. In SNA Server, an indicator that signifies the readiness of a receiving component to accept another pacing group. The indicator is carried in a response header (RH) for session-level pacing, and in a transmission header (TH) for virtual-route pacing.

pack loop. A loop that packs active cells of a sparse array into successive cells in another array, so that the resulting array contains no empty cells between its first and last active cells.

package. (1.) An installable unit of a software product. Software product packages are separately installable units that can operate independently from other packages of that software product. (2.) In Ada language, specifies a group of logically related entities, such as types, objects of those types, and subprograms with parameters of those types. It is written as a package declaration and a package body. The package declaration has a visible part, containing the declarations of all entities that can be explicitly used outside the package. It may also have a private part containing structural details that complete the specification of the visible entities, but which are irrelevant to the user of the package. The package body contains implementations of subprograms (and possibly tasks as other packages) that have been specified in the package declaration. A package is one of the kinds of program unit. See also private part.

package closure. The set of classes that need to be supported to be able to create all possible instances of all classes defined in the package.

packet. In data communications, a sequence of binary digits, including data and control signals, that is transmitted and switched as a composite whole. The data, call control signals, and error control information are arranged in a specific format. See also call-accepted packet, call-connected packet, call-request packet, clear-confirmation packet, clear-indication packet, clear-request packet, data packet, incoming-call packet, interrupt packet, interrupt-confirmation packet, reset-request packet, reset-confirmation packet, address field, and restart-confirmation packet.

packet assembler/disassembler (PAD). In X.25 communications, equipment used for connecting asynchronous (start/stop) devices to an X.25 network.

packet header. In X.25 communications, control information at the start of the packet; the contents of the packet depend on the packet type.

packet level. In X.25 communications, the packet format and control procedures for the exchange of packets containing control information and user data between the data terminal equipment (DTE) and the data circuit-terminating equipment (DCE). Synonymous with level 3. See also level, frame level, datalink level, and physical level.

packet-level interface. In X.25 communications, the level of the DTE/DCE interface in packet mode operation relating to the exchange of data and signaling, where this information is contained in packets. See also frame-level interface.

packet mode operation. Synonym for packet switching.

packet size. In X.25 communications, in the context of data packets, refers to the length of the user data.

packet switching. Routing and transferring data by addressing packets so that a channel is occupied only during packet transmission. On completion of the transmission, the channel is available for transfer of other packets. Synonymous with packet mode operation. See also circuit switching.

packet window. In X.25 communications, the number of packets that can be outstanding without acknowledgment. See also frame window and window.

packing. In AIXwindows and Enhanced X-Windows, the grouping of children objects within a parent container object. If the children are closely packed, the common distance between their borders is minimal; if they are loosely packed, the common distance border-to-border is maximized.

pad. (1.) To fill unused positions in a field with dummy data, usually zeros or blanks. (2.) A device used to introduce transmission loss into a circuit. It can be inserted to introduce loss or match impedances.

padding. Bytes inserted in the data stream to maintain alignment of the protocol requests on natural boundaries. Padding increases the ease of portability to some machine architectures.

page. (1.) A block of instructions, data, or both. (2.) The number of lines that can fit into a window. (3.) In a virtual storage system, a fixed-length block that has a virtual address and is transferred as a unit between real storage and auxiliary storage. (4.) A contiguous 4096-byte portion of a virtual-memory segment. The offset of each page from the beginning of the segment is an integral multiple of 4096. See also leaf.

page cluster. A type of memory buffer that is constructed from a full memory page (normally 4096 bytes).

page fault. (1.) A program interruption that occurs when an active page refers to a page that is not in memory. (2.) An interrupt that occurs when the processor attempts to access a virtual-memory page that is not in real memory.

page frame. (1.) In real storage, a storage location having the size of a page. (2.) An area of main storage that contains a page. (3.) A 4096-contiguous-byte portion of real memory that is used to hold a virtual-memory page.

page frame table. A table, contained in real memory, that contains the real memory locations of all currently defined pages.

pagination. (1.) The process of adjusting text to fit within page margins. (2.) In word processing, the automatic arrangement of text according to a preset number of page layout parameters.

paging. (1.) The action of transferring instructions, data, or both between real storage and external page storage. (2.) Moving data between memory and a mass storage device as the data is needed. (3.) In System/370 virtual storage systems, the process of transferring pages between real storage and external page storage.

paging device. A disk device used to store pages of memory that are not currently in real memory.

paging space. Disk storage for information that is resident in virtual memory but is not currently being accessed.

paint. In computer graphics, to shade an area of a display image.

PAL. (1.) Programmable array logic. (2.) A national television industry broadcasting standard used in Europe and some other countries. See also NTSC and SECAM.

PAL signal. A phase analog lock signal, also called composite video. The European standard for composite video.

palette. (1.) Location for building customized components and parenting them with other components. Subsequently, components can be reused by copying and moving them to other interfaces. (2.) In CDE, a range of graphically displayed choices, such as colors or collections of tools, that you can select in an application.

pane. On a display screen, the inner portion of a window used to present information to the user. A window can consist of one or more panes. See also menu pane.

panel. (1.) A set of logically related information displayed on the screen for the purpose of communicating information to or from a computer user. (2.) A group of one or more panes that are treated as a unit. The panes of a panel are displayed together, erased together, and usually represent a unit of information to a person using the application. A panel is represented on the display as a rectangular area tiled (completely filled) with panes.

panning. (1.) In computer graphics, the viewing of an image that is too large to fit on a single screen by moving from one part of the image to another. (2.) Progressively translating an entire display image to give the visual impression of lateral movement of the image.

paragraph. (1.) Text that is separated from other text by blank lines. (2.) In word processing, one or more sentences that maybe preceded by or followed by an appropriate indicator.

parallel channel. Communications protocol between controller and mainframe processors.

parallel device. A device that can perform two or more concurrent activities. Contrast with serial device.

parallel processing. The condition in which multiple tasks are being performed simultaneously within the same activity. Contrast with serial processing.

parallel transmission. (1.) Transmitting all bits of a character simultaneously. (2.) In data communication, the simultaneous transmission of a number of signal elements that constitute the same telegraph or data signal.

parameter. (1.) Information that the user supplies to a panel, command, or function. (2.) A variable that is given a constant value for a specified application. (3.) Data passed between programs or procedures. (4.) In Ada language, a parameter is one of the named entities associated with a subprogram, entry, or generic unit, and used to communicate with the corresponding subprogram body, accept statement or generic body. A formal parameter is an identifier used to denote the named entity within the body. An actual parameter is the particular entity associated with the corresponding formal parameter by a subprogram call, entry call, or generic instantiation. The mode of a formal parameter specifies whether the associated actual parameter supplies a value for the formal parameter, or the formal supplies a value for the actual parameter, or both. The association of actual parameters with formal parameters can be specified by named associations, by positional associations, or by a combination of these. See also formal parameter and mode.

parameter block. A block of memory that contains specific parameters for an ioctl operation.

parameter declaration. Description of a value that a function receives. A parameter declaration determines the storage class and the data type of the value.

parametric bicubic surface. A surface defined by three equations. The x equation is: x(u,v) = a11u3v3 + a12u3v3 + a13u3v + a14u3 + a21u2v3 + a22u2v2 + a23u2v + a24u2 + a31uv3 + a32uv2 + a33uv + a34u + a41v3 + a42v2 + a43v + a44. The equations for y and z are similar. The points on a bicubic patch are defined by varying the parameters u and v from 0 to 1. If one parameter is held constant and the other is varied from 0 to 1, the result is a cubic curve. If w(u,v)=1 for all u,v, the bicubic surface is called "ordinary," but if w(u,v) varies as a function of u,v, then the surface is called "rational." See also homogeneous coordinates.

parametric component. In AIXwindows, a simple mechanism that delivers all the functions necessary for most applications, yet is easier and less time consuming to build.

parametric cubic curve. A curve defined by the equation: x(t) = axt3 + bxt2 + cxt + dx; y(t) = ayt3 + byt2 + cyt + dy; z(t) = azt3 + bzt2 + czt + dz; w(t) = awt3 + bwt2 + cwt + dw. Wherex, y, z, and w are cubic polynomials. The parameter t typically varies between 0 and 1. Such a curve is considered rational only if a(w), b(w), or c(w) is not equal to 0; otherwise, it is simply an ordinary parametric curve. See also B-spline cubic curve, Bezier cubic curve, and cardinal spline cubic curve.

parent. (1.) A process that has spawned a child process using the fork primitive. (2.) Pertaining to a secured resource, either a file or library, whose user list is shared with one or more files or libraries. Contrast with child. (3.) In AIXwindows and Enhanced X-Windows, a graphical object that controls one or more smaller graphical objects attached to it. The smaller graphical objects are called children, and they are automatically deleted when their parent is deleted. (4.) In Ada language, the associated specification of a package body or subprogram body. The parent of a subunit is the body in which it was declared.

parent class. In SOM, a class from which another class inherits instance methods, attributes, and instance variables. A parent class is sometimes called a base class or superclass.

parent device. A hierarchical location term. It indicates what device the device you are concerned with connects to. For example, the parent device of an SCSI disk might be an SCSI adapter.

parent directory. The directory one level above the current directory. See also parent folder.

parent folder. In CDE, a folder that contains subfolders and files. When discussing command-line activities, this may be called the parent directory. See also subfolder.

parent ID. The character sequence identifying the graphical object that controls smaller graphical objects, called children.

parent method call. In SOM, a technique where an overriding method calls the method procedure of its parent class as part of its own implementation.

parent type. For Ada programming, see derived type.

parent window. In Enhanced X-Windows, the window that controls the size and location of its children. If a window has children, it is a parent window.

parity bit. A binary digit (bit) appended to a group of binary digits to make the sum of all digits in the group either always odd (odd parity) or always even (even parity).

parity check. A test to determine whether the number of ones (or zeros) in an array of binary digits is odd or even.

parity error. A transmission error that occurs when the received data does not have the parity expected by the receiving system. This error is usually caused by the sending and receiving systems having different parity settings.

parse. (1.) In systems with time sharing, to analyze the operands entered with a command and create a parameter list for the command processor from the information. (2.) Before a command line interpreter can convert an operating-system command into an executable form of machine code, the command must be broken down into easily coded elements, or"parsed", by the interpreter.

parser. A program that interprets user input and determines what to do with the input. See also grammar rules.

participant. An application is a participant in a transaction when it either initiates the transaction or receives a request on behalf of that transaction.

partition. (1.) A logical division of storage on a fixed disk. (2.) A fixed-size division of storage.

partner. In data communications, the remote application program or the remote computer.

Pascal. A high-level, general-purpose programming language. Programs written in Pascal are block-structured, consisting of independent routines.

pass-by-CONST. In Pascal, the parameter-passing mechanism by which the address of a variable is passed to the called routine. The called routine is not permitted to modify the formal parameter. Synonymous with pass-by-read-only-reference.

pass-by-read-only-reference. Synonym for pass-by-CONST.

pass-by-read/write-reference. Synonym for pass-by-VAR.

pass-by-value. In Pascal, the parameter-passing mechanism by which a copy of the value of the actual parameter is passed to the called routine. If the called routine modifies the formal parameter, the corresponding actual parameter is not affected.

pass-by-VAR. In Pascal, the parameter-passing mechanism by which the address of a variable is passed to the called routine. If the called routine modifies the formal parameter, the corresponding actual parameter is also changed. Synonymous with pass-by-read/write-reference.

pass-through function. The ability to pass data through a program transparently, without alteration.

pass-through mode. The mode of use provided by the VM/Pass-ThroughFacility, which allows VM display station users to interactively access a VM system, including the one to which the terminal is attached. It also allows users to access non-PVM systems that support Remote 3270 Binary Synchronous Communication (BSC) display stations and 4300 processors having the Remote Operator Console Facility (ROCF). A user can access, log on to, and use another system in a defined network as though the user's local terminal were directly connected to that system. PVM activities become transparent to the user once logged on to the target system.

passive gateway. A gateway that does not exchange routing information. Its routing information is contained indefinitely in the routing tables and is included in any routing information that is transmitted. Contrast with active gateway.

passive grab. In Enhanced X-Windows, grabbing a key or button is a passive grab. The grab becomes an active grab when the key or button is actually pressed. Contrast with active grab. See also grab, button grabbing, pointer grabbing, and key grabbing.

password. (1.) A string of characters known only to the user and the system. The user must specify the correct password to gain access to a system and the data stored with it. (2.) A string encoded with information about a software vendor (vendor password) or about a software product (product password).

password security. The process of requiring a user to enter a password to log in to a system.

patch. A parametric bicubic surface.

path. (1.) In SNA, the series of path control network components traversed by the information exchanged between two network addressable units (NAUs). A path consists of a series of path control elements, data link control elements, and links. (2.) In a network, any route between any two nodes. (3.) In a database, a sequence of segment occurrences from the root segment to an individual segment. (4.) In the InfoExplorer program, the list of articles you followed to get to the article that is currently displayed. (5.) In CDE, a text string that specifies the hierarchical location of a folder (directory).

path list. The structure, or the corresponding parameter, containing the full path name for a file.

path name. A file name specifying all directories leading to the file. See also full path name and relative path name.

pattern. (1.) A regular expression or series of regular expressions that define the search pattern. (2.) In GL, a 16x16, 32x32, or 64x64 array of bits defining the texturing of polygons on the system display.

pattern-action. When the awk command finds a pattern in an input data file that matches a line in the program file, it performs the associated action on that line.

pattern address. Reference to a line by a string contained within the line, rather than by a numerical or symbolic address. A pattern address can be a character string or a regular expression. See also symbolic address.

pattern matching. Specifying a pattern of characters that the system should find.

pattern-matching character. Special characters such as * (asterisk) or ? (question mark) that can be used in a file specification to match one or more characters. For example, placing a ? in a file specification means that any character can be in that position. Synonymous with wildcard.

pattern strings. Strings of regular expressions composed of special pattern-matching characters. The pattern strings can be used in addresses to specify lines and, in some subcommands, portions of a line.

PBX. Private Branch Exchange. A private telephone system that performs automatic selection of outside lines.

PC. Personal computer.

PCI. Programmed Control Interrupt.

PCM. Physical Connection Management.

PCS. See programmable character set.

PDN. See public data network.

PE. Phrase Encoded, a magnetic tape recording format with a density of 1600 bpi.

peak rate. The maximum speed at which a device could operate under ideal conditions, if its designer were choosing the workload.

peer-to-peer communications. Pertaining to data communications between two nodes that have equal status in the interchange. Either node can begin the conversation. See also Logical Unit Type 6.2.

peer trust. A type of trust relationship established between two cells by means of a secret key shared by mutual authentication surrogates maintained by the two cells. A peer trust relationship enables principals in the one cell to communicate securely with principals in the other.

pel. See picture element.

pending. Waiting, as in an operation that is pending.

pending state. A condition of a server program in which it has received a request for an action (start, stop, or suspend) but has not yet performed that action.

PEP. Packet Exchange Protocol. A datagram service that is implemented by a user-level library, using IDP datagram sockets.

per-process data area. In kernel mode, a portion of the user process stack segment. This area is paged with the process and it contains process information such as the current directory of files opened by the process or input in I/O mode. This information occupies the top of the stack segment. See also user block and user structure.

peripheral device. With respect to a particular processing unit, any equipment that can communicate directly with that unit.

peripheral unit. See peripheral device.

permanence. A basic property of transaction processing systems. This term means that once a transaction has committed, the modifications made to data by that transaction must be permanent. Subsequent transactions requesting the data modified by a previous transaction must always see the new data. These changes must be preservable even in the event of a system failure.

permanent error. An error that cannot be eliminated by retrying an operation.

permanent link. A connection below a multiplexer that can exist without having an open controlling stream associated with it.

permanent storage. A storage device whose contents cannot be modified.

permanent virtual circuit (PVC). In X.25 communications, a virtual circuit that has a logical channel permanently assigned to it at each DTE. Call-establishment protocols are not required. Contrast with switched virtual circuit. See also virtual circuit.

permission. The modes of access to a protected object.

permission code. A three-digit octal code or a nine-letter alphabetic code that indicates access permissions. The access permissions are read, write, and run. See also access permission.

permission field. One of the three-character fields within the permissions column of a directory list. The permission field indicates the read, write, and run permissions for the file or directory owner, for the group, and for all others.

permissions. Codes that determine how the file can be used by any users who work on the system. In Common Desktop Environment, a set of flags that determine a user's access to files and directories, which you can see using the Properties... command on the File menu.

persistence. In Display PostScript (DPS), a specified character set that is used for all subsequent text segments in a compound string until a new character set is encountered.

persistent data. Data which retains its value across multiple runs of transactional applications, regardless of system failures or restarts.

persistent object. In SOM, an objectwhose state can be preserved beyond the termination of the process that created it. Typically, such objects are stored in files.

persistent segment. A segment whose pages have permanent locations on disk, rather than temporary slots in the paging space.

perspective projection. A technique used to achieve realism when drawing primitives. In a perspective projection, the lines of projection meet at the viewpoint; thus, the size of a primitive varies inversely with its distance from the source projection. The farther a primitive or part of a primitive is from the viewer, the smaller it will be drawn. This effect, known as perspective foreshortening, is similar to the effect achieved by photography and by the human visual system. See also orthographic projection.

peta. Two to the fiftieth power.

PEX. A protocol for supporting three-dimensional graphics.

PEXlib. A programmer's interface to the PEX protocol.

PFM. See program fault management.

phase. (1.) One of several stages of file system checking and repair performed by the fsck command. (2.) A distinct part of a process in which related operations are performed. (3.) A part of a sort and merge program, such as sort phase and merge phase. (4.) A part of a data call.

phase modulation. Altering the phase of a carrier signal to convey data signals.

PHIGS. See Programmers' Hierarchical Interactive Graphics System.

phototypesetter. A typesetting machine that operates by projecting light through film matrices of the type characters upon light-sensitive paper or film.

physical block. See block.

physical data block. See block.

physical device. See device.

physical file. (1.) An indexed file containing data for which one or more alternative indexes have been created. (2.) A database file that describes how data are to be presented or received from a program and how data are actually stored in the database. A physical file contains one record format and one or more members.

physical layer. The lowest layer of network design as specified by the ISO Open System Interconnection (OSI) reference model. This layer is responsible for interfacing with the medium, detecting and generating signals on the medium, and converting and processing signals received from the medium and from the data link layer. See also physical level.

physical level. In X.25 communications, the mechanical, electrical, functional, and procedural media used to activate, maintain, and deactivate the physical link between the data terminal equipment (DTE) and the data circuit-terminating equipment (DCE). Synonymous with level 1. See also level, frame level, data-link level, packet level, and physical layer.

physical network. A network of machines linked by physical network cabling, modems, or other hardware. A physical network can contain one or several logical networks.

physical partition (PP). The smallest unit of disk-space allocation for a logical volume. The physical partition is contiguous space on a physical volume. A fixed-size portion of a physical volume. One or more physical partitions constitute the underlying physical storage medium for a logical partition.

physical unit (PU). In SNA, a set of programs that control the actual physical hardware associated with a node.

physical volume (PV). (1.) The portion of a single unit of storage accessible to a single read/write mechanism; for example, a drum, a disk pack, or part of a disk storage module. (2.) A read-write fixed disk physically attached to a computer. The actual storage space provided by a single fixed-disk drive. See also log volume.

picking. In computer graphics, a method for finding out what primitives are being drawn near the cursor on the display screen. See also hit, picking region, selecting, and selecting region.

picking region. A rectangular volume around the cursor that is sensitive to picking events. If a drawing primitive draws within this volume, a pick event is reported. The width and height of the region can be set by the user. If the z-buffer is enabled, the depth of the region is the entire z-buffer. See also hit, selecting, picking, and selecting region.

picture. A pixmap used for displaying Common Desktop Environment icons, background patterns, and controls.

picture element (pel). (1.) In computer graphics, the smallest element of a display space that can be assigned color and intensity independently. (2.) A point in the frame buffer or on the display. See also pixel.

PID. See process ID.

piecewise linear curve. A list of coordinate pairs in the parameter space for the Non-Uniform Rational B-Spline (NURBS) surface. These points are connected with straight lines to form a path.

pin. (1.) An area of memory reserved for certain functions. (2.) One of the connectors in an adapter plug.

PIO. See programmable input/output operation.

PIP. See Program Initialization Parameters.

pipe. (1.) To direct the data so that the output from one process becomes the input to another process. The standard output of one command can be connected to the standard input of another with the pipe operator ( | ). Two commands connected in this way constitute a pipeline. (2.) A one-way communication path between a sending process and a receiving process. See also pipeline.

pipeline. (1.) A direct, one-way connection between two or more processes. (2.) A serial arrangement of processors or a serial arrangement of registers within a processor. Each processor or register performs part of a task and passes results to the next processor. Several parts of different tasks can be performed at the same time. (3.) To perform processes in a series. (4.) For increased processing speed, to start the running of an instruction sequence before the previous instruction sequence is completed. See also pipe.

pipeline options. In GL, variables that control the flow of processing in the graphics pipeline. For instance, lighting is a pipeline option. If lighting is turned on, the color of a primitive is obtained by evaluating the lighting equations. If lighting is turned off, the last color specified is used. Other pipeline options are the back-facing flag, the shade-model flag, the depth-cueing flag, the picking flag, the color-mode (color index or RGB) flag, the z-buffer flag (enables or disables drawing to the z-buffer), and so on. See also attribute.

pitch. A unit of width of typewriter type, based on the number of times a letter can be set in a linear inch. For example, 10-pitch type has 10 characters per inch.

pixel. A rectangular picture element. The smallest element used to compose an image, a single dot. A display screen is composed of an array of pixels. In a black-and-white system, pixels are turned on and off to form images. In a color system, each pixel has three components: red, green, and blue. The intensity of each component can be controlled. See also picture element.

pixel map. A three-dimensional array of bits. A pixel map can be thought of as a two-dimensional array of pixels, with each pixel being a value from zero to 2 to the N -1, with N as the depth of the pixel map. Synonym for pixmap.

pixel value. In Enhanced X-Windows, the number of bit planes used in a particular window or pixmap. For a window, a pixel value indexes a color map and derives an actual color to be displayed. A pixel is an N-bit value, where N is the number of bit planes (the depth) used in a particular window or pixmap.

pixmap. (1.) Synonym for pixel map. (2.) In AIXwindows and Enhanced X-Windows, a data type to which icons (originally created as bitmaps) are converted. Once this conversion takes place, the appropriate AIXwindows subroutines can generate pixmaps through references to an .Xdefaults file (by name) and through an argument list (by pixmap). See also image cache.

placeholder. An object, component or file that only exists to mark the position of an intended entity.

plaintext. The input to an encryption function or the output of a decryption function. Decryption transforms ciphertext into plaintext.

plane. When a pixmap or window is thought of as a stack of bitmaps, each bitmap is called a plane or bit plane.

plane mask. (1.) Determines which of the display adapter storage places are modified by the output functions. (2.) In Enhanced X-Windows, a bit mask restricting graphics operations to affect a subset of bit planes. It is stored in a graphics context. Graphics operations can be restricted to affect only a subset of bit planes of a destination.

platen. The support mechanism for paper on a printer, commonly cylindrical, against which printing mechanisms strike to produce an impression.

playing back. In Encina, the actions of the Recovery Service when a TP system using recoverable data is restarted. When started, the Recovery Service plays back log records for transactions that have prepared but which were not actually committed, guaranteeing that the state of that recoverable data reflects the records maintained by the TP system.

PList. An array of pointers with a suite of operations for adding and removing elements in various ways.

plotter. A hard copy device, attached to the system with cables, that prints two-dimensional graphs and charts.

plug. A device that connects the wires of an electrical circuit to an electrical source. The plug is designed to be inserted into a jack.

PMF. Parameter management frame.

PMP. See Preventive Maintenance Package.

PMR. See Problem Management Record.

point. (1.) A unit of typesetting measure equal to 0.01384 inch (0.3505 mm), or about 1/72 of an inch. There are 12 points per pica. (2.) In CDE, to move the mouse until the pointer rests on a particular screen element or area.

point-handle. A point within a graphic object.

point-to-point link. A switched or nonswitched link that connects a single remote link station to a node or to another station.

pointer. (1.) A variable that holds the address of a data object. (2.) A physical or symbolic identifier of a unique target. (3.) In computer graphics, the device attached to the cursor and tracked on the screen.

pointer grabbing. In Enhanced X-Windows, a client can actively grab control of the pointer so that button and motion events will be sent to that client rather than the client to which the events normally would have been sent. See also grab, button grabbing, and key grabbing.

pointer to member. Used to access the address of nonstatic members of a C++ class.

pointer type. A data type that defines variables containing addresses and, sometimes, other information about variables.

pointing. Positioning the pointing cursor on a displayed object. The action of lining up the mouse pointer so that the pointer lies on top of something.

pointing device. In Enhanced X-Windows, a device with effective dimensional motion, usually a mouse. One visible cursor is defined by the Core protocol, and it tracks whatever pointing device is attached as the pointer.

polar coordinates. A coordinate system in which positions are measured as a distance from the origin and an angle from some reference direction (usually, counterclockwise from the x-axis).

poll. (1.) In data communications, an interrogation that determines whether a station is ready to transmit information. (2.) To run a polling sequence.

polled I/O devices. Devices (keyboard, mouse, button, dials) whose current values are read by the user process.

polling. (1.) On a multipoint connection or a point-to-point connection, the process whereby data stations are invited, one at a time, to transmit data. (2.) Interrogation of devices so as to avoid contention, determine operational status, or determine readiness to send or receive data.

polyline. In computer graphics, a sequence of adjoining lines.

polymarker. In computer graphics, a sequence of markers. The definition of the marker includes specific attributes such as color, style, width, height, pattern, and origin.

polymorphic functions. Functions that can be applied to objects of more than one data type. C++ implements polymorphic functions in two ways: overloaded functions (calls are resolved at compile time); and virtual functions (calls are resolved at run-time).

polymorphism. An object-oriented programming feature that may take on different meanings in different systems. Under various definitions of polymorphism, (a) a method or procedure call can be executed using arguments of a variety of types, or (b) the same variable can assume values of different types at different times, or (c) a method name can denote more than one method procedure. The SOM system reflects the third definition (for example, when a SOM class overrides a parent class definition of a method to change its behavior). The term literally means "having many forms."

pop. A term used when a module that is immediately below the stream head is removed.

pop-down. In Enhanced X-Windows, an action referring to a type of widget that closes when a pointer button is released.

pop up. (1.) In Enhanced X-Windows, a box on the display screen that displays information or asks you to make choices. (2.) In Enhanced X-Windows, an action referring to a type of widget that opens automatically when a pointer button is held down within certain windows. (3.) To use a widget to create a window outside the window hierarchy defined by the widget tree.

pop-up cascade. In Enhanced X-Windows, several spring-loaded pop-ups emanating in succession from one modal pop-up.

pop-up child. In Enhanced X-Windows, a child on the pop-up list.

pop-up list. A list of pop-up children stored in a widget.

pop-up menu. (1.) Synonym for popup. (2.) In AIXwindows, a type of MenuPane widget that appears as the result of some user action (usually clicking a mouse button) and then disappears when the action is completed. (3.) The interface definition for translation actions. (4.) In CDE, a menu that, when requested, is displayed next to the object with which it is associated. Pop-up menus are usually displayed by clicking mouse button 3 or pressing Shift+F10.

pop-up widget. In Enhanced X-Windows, a window child of the root that is attached to its widget parent differently than the normal widget; a pop-up widget is not geometrically constrained by its parent widget.

pop-up window. Any window that opens automatically when activated. See also pop-up.

popdown. In AIXwindows, the manner in which a type of MenuPane widget disappears suddenly (pops down) in the display when some user action (usually clicking a mouse button) is completed.

popup. In AIXwindows, the manner in which a type of MenuPane widget appears suddenly (pops up) in the display as the result of some user action (usually clicking a mouse button). Synonym for pop-up menu. See also pop-up window.

POR. See power-on reset.

port. (1.) A part of the system unit or remote controller to which cables for external devices (display stations, terminals, or printers) are attached. The port is an access point for data entry (input) to or exit from (data output) a computer system. (2.) An entrance to or exit from a network. (3.) To make the programming changes necessary to allow a program that runs on one type of computer to run on another type of computer. (4.) In NCS, a specific communications end point within a host. A port is identified by a port number. See also socket and listening.

portability. The characteristic that determines whether a source program can be compiled and run on computers of different architectures without requiring recoding.

portable character set. In the XPG4 system interface, the collection of characters present in all locales supported by XSI-conformant systems: Or ABCDEFGHIJKLMNOPQRSTUVWXYZ


0123456789!#%^&*()_+-={}[] :"~;'`<>?,.|\/@$

Also included are the alert, backspace, tab, newline, vertical-tab, form-feed, carriage-return, space characters, and the null character, NUL.

portable file name character set. In the XPG4 system interface, the set of characters from which portable file names are constructed. For a file name to be portable across implementations of the XPG4 and ISO POSIX-1 standard, it must consist only of the following characters: ABCDEFGHIJKLMNOPQRSTUVWXYZ



The last three characters are the period, underscore, and hyphen characters, respectively. The hyphen must not be used as the first character of a portable file name. Uppercase and lowercase letters retain their unique identities between conforming implementations. In the case of a portable path name, the slash character can also be used.

Portable Operating System Interface For Computer Environments (POSIX). An IEEE standard for computer operating systems.

portrait display. A rectangular display that is taller than it is wide. See also landscape display.

portrait upside-down. A page orientation such that the top of the printed image is at the trailing edge of the paper as it emerges from the printer.

POS registers. Programmable Option Select registers. A set of registers that allow the software to automatically configure devices on the Micro Channel bus at the time the machine is turned on. These registers allow the setup software (which is run at the time the machine is turned on) to automatically identify the adapter and to set up various parameters on the adapter such as its starting address and interrupt level.

position. (1.) Any location in a string that may be occupied by an element and that is identified by a serial number. (2.) The location of a character in a series, as in a record, a displayed message, or a computer printout.

position (within an attribute). The ordinal position of one value relative to another.

position (within a string). The ordinal position of one element of a string relative to another.

positional association. In Ada language, specifies the association of an item with a position in a list, by using the same position in the text to specify the item.

positional parameter. (1.) A shell facility that assigns values from the command line to variables in a program. (2.) A parameter that must appear in a specified location relative to other positional parameters.

POSIX. See Portable Operating System Interface For Computer Environments.

post. The action required to make a pop-up or pull-down menu appear. This action is normally a click or button press on one of the mouse buttons.

POST. See power-on self-test.

post processor. A computer program that effects some final computation or organization. In text formatting, a postprocessor command translates the output of the nroff and troff commands for use on certain printers, typesetters, or phototypesetters.

posted event. A notification sent to the DLC by its attached device handler by way of the e_post system call.

PostScript. A graphics language used to drive output of text and graphics. Trademark of Adobe Systems, Inc.

pound (lb). Unit of measurement for weight equal to 16 ounces or 454 grams.

power factor. The ratio of power consumed to the volt amps (apparent power).

power-on light. The light on the operator panel that indicates that the DC power in the system unit is functioning.

power-on reset (POR). A key sequence that restarts the operating system (or other program) without turning off the electrical power of the system.

power-on self-test (POST). A series of internal diagnostic tests activated each time the system power is turned on.

power requirement. The actual power consumed by a computer system, measured in watts.

power source. The minimum acceptable rating of the electrical circuit providing power to a computer system, measured in volt amps (kVA).

PPA (physical point of attachment). The point at which a system attaches itself to a physical communications medium.

PPA identifier. An identifier of a particular physical medium over which communication occurs.

P(R). In X.25 communications, the packet receive sequence number.

pragma. In Ada language, conveys information to the compiler.

precedence. (1.) The priority system for grouping different types of operators with their operands. (2.) In programming languages, an order relation defining the sequence of the application of operators within an expression.

precision. (1.) A measure of the ability to distinguish between nearly equal values. See also single precision and double precision. (2.) The degree of discrimination with which a quantity is stated. For example, a three-digit numeral discriminates among 1000 possibilities. (3.) In GL, the number of digits that are printed or displayed. (4.) The number of straight line segments used to approximate one segment of a spline.

preconnected file. A unit or file that was defined at installation time. For example, standard input and standard output are preconnected files.

Predefined Connection Object Class. Specifies the kind of connections that can be made to a device and where.

predefined convention. In FORTRAN, the implied type and length specification of a data item based on the initial character of its name, when no explicit specification is given. The initial characters I through N imply type integer of length 4; the initial characters A through H, O through Z, $, and _ imply type real of length 4.

predefined database. Contains configuration data for all possible devices supported by the system. See also Device Configuration Database and Customized Database.

Predefined Devices Object Class. Represents each device type, as determined by class, subclass, and type. The Predefined Devices Object Class contains basic information about the devices, such as device method names and how to access the information contained in the other object classes.

predicate. Boolean logic term denoting a logical expression that determines the state of some variables. For example, a predicate can be an expression stating that "variable A must have the value 3." The control expression used in conjunction with condition variables is based upon a predicate. Use a condition variable to wait for some predicate to become true, for example, to wait for something to be in a queue.

preferential CUG. In X.25 communications, the default closed user group.

prefix. In Ada language, used as the first part of certain kinds of name. A prefix is either a function call or a name. See also name.

preinstalled. Software that is installed by the manufacturer and ready to use.

premultiplication. In GL, matrix multiplication on the left. If a matrix M is premultiplied by a matrix T, the result is TM.

preprocessor. (1.) A functional unit that effects preparatory computation or organization. (2.) In emulation, a program that converts data from the format of an emulated system to the format accepted by an emulator. (3.)A program that examines the source program for preprocessor statements, which are then run, resulting in the alteration of the source program. (4.)A program that modifies, and possibly optimizes, source programs before they are processed by a compiler.

preprocessor statement. In C language, a statement that begins with the # (pound sign) and contains instructions that the preprocessor interprets.

prerequisite. A software product or a service update that must be installed before another software product or service update is installed. If you attempt to install software products or service updates without the required prerequisite software, a system message displays the names of required prerequisite software. Contrast with dependent.

presentation address. An unambiguous name that is used to identify a set of presentation service access points. Loosely, it is the network address of an OSI service. See also address.

Presentation Service Access Point (PSAP). Address of an OSI communications partner. It addresses an application in a computer.

presentation space. An array that contains the data and attributes associated with a window.

preservation installation. An installation method used when a previous version of BOS is installed on your system and you want to preserve the user data in the root volume group. However, this method overwrites the /usr, /tmp, /var,and /(root) file systems, so any user data in these directories is lost. System configuration must be done after doing a preservation installation.

Preventive Maintenance Package (PMP). A maintenance level update for your system. A PMP includes updates for the Base Operating System (BOS) and for each optional software product that is installed on your system.

primary. An irreducible unit of data. For example, a single constant, variable, or array element.

Primary Enterprise Systems Connection Manager. In multiple ESCM environments, the source of ESCM commands.

primary expression. An identifier, parenthesized expression, function call, array element specification, structure member specification, or union member specification.

primary group. In concurrent groups, the group that is assigned to the files that you create.

primary language. The primary locale you want your system to use for screen information.

primary navigation article. The general, top-level unit of software documentation.

primary representation. The form in which the service supplies an attribute value to the client.

primary selected text. A text group selected as a primary target or destination, especially text selected within a text field that can be passed to a function. Also, the first block of text specified in a function or statement. See also primary selection.

primary selection. In AIXwindows, the text selected in a widget. The primary selection has a value retrieved by the XmTextGetSelection function. See also primary selected text.

primary slow poll. A technique used by primary link stations to reduce nonproductive polling of a secondary link station.

primary station. (1.) On a point-to-point channel, the station that gains control of the channel first. On a multipoint channel, the station controlling communications. (2.) In high level data link control (HLDC), the part of a data station that supports the primary control functions of the data link, generates commands for transmission, and interprets received responses. (3.) In SNA, the station on an SDLC data link that is responsible for control of the data link. There can be only one primary station on a data link. All traffic over the data link is between the primary station and a secondary station.

prime file. In Pascal, a file containing precompiled declarations in the internal table format of the Pascal compiler. Prime files are used to initialize the internal tables of the compiler before compilation begins.

primitive. A drawing command, such as arc, line, circle, polygon, or charstr. Such commands are called primitives because they are not made up of smaller parts, and because they are the basic pieces out of which more complex scenes can be composed. Also used to describe the figures created by drawing commands.

Primitive. In Enhanced X-Windows, the Primitive class provides the resources and functionality for the low-level widgets that are managed by the manager class. Primitive class widgets cannot have normal child widgets but they can have pop-up child widgets.

primitive coordinates. The space in which a primitive is defined. A convenient point is chosen as the origin and the primitive is defined relative to this point. Synonym for primitive space. See also eye coordinates, screen coordinates, and world coordinates.

primitive font. A font in which characters are defined as primitives. Like all other primitives, primitive font characters can be scaled and rotated. See also raster font and font.

primitive space. Synonym for primitive coordinates.

primitive widget. In Enhanced X-Windows, a widget that instantiates its own children of a known class and does not expect external clients to do so. Primitive widgets do not have general geometry management methods. Primitive widgets that instantiate children are responsible for all operations requiring downward traversal below themselves. See also widget.

principal identifier. The name used to identify a principal uniquely.

Print Manager. In CDE, a software application that shows all the printers on your system.

print queue. A file containing a list of the names of files waiting to be printed.

print server. In CDE, a host computer to which one or more printers are connected, or the UNIX process that manages those printers.

printer. A device externally attached to the system unit, used to print system output on paper.

Printer control. In CDE, the Front Panel control used to start the Printer software application. Dropping a file on the control displays a dialog box you can use to print the file to the default printer.

Printer Jobs. In CDE, a software application that provides information about jobs on a single printer.

printer session. A 3270 Host Connection Program 2.1 and 1.3.3 (HCON) mode of operation during interaction with a host computer that emulates a 3286/87 printer.

printing device. Any printer or other device that prints, such as a typewriter-like device or a plotter.

printout. Information from the computer produced by a printer.

priority. (1.) A rank assigned to a task that determines its precedence in receiving system resources, the CPU in particular. (2.) The relative significance of one job to other jobs in competing for allocation of resources. The importance or urgency of a process.

priority number. A number that establishes the relative priority of printer requests.

priority value. A number maintained by the scheduler for each process that indicates the priority of that process. The smaller the priority value of the process, the higher its priority.

privacy. A protection level that may be specified in secure RPC communications and that encrypts RPC argument values.

private. A private member of a C++ class is only accessible to member functions and friends of that class.

private object. (1.) In XDS, an OM object created in a workspace using the object management functions. (2.) In XOM, an object that is represented in an unspecified fashion.

private part. For Ada programming, see package.

private type. In Ada language, a type whose structure and set of values are clearly defined, but not directly available to the user of the type. A private type is known only by its discriminants (if any) and by the set of operations defined for it. A private type and its applicable operations are defined in the visible part of a package, or in a generic formal part. Assignment, equality, and inequality are also defined for private types, unless the private type is limited.

privileged instructions. System control instructions that can only run in the processor's privileged, or supervisor, state. Privileged instructions generally manipulate virtual machines or the memory manager and are not used ordinarily by application programmers. See also privileged state.

privileged state. A hardware protection state in which the processor can run privileged instructions. Contrast with unprivileged state. See also privileged instructions.

privileged user. A user logged into an account with root user authority.

problem determination. The process of identifying the source of a problem. Often this process identifies programs, equipment, data communications facilities, or user errors as the source of the problem.

problem determination procedure. A prescribed sequence of steps aimed at recovery from, or circumvention of, problem conditions.

Problem Management Record (PMR). A number assigned by a support center to a reported problem.

problem state. (1.) One of two virtual machine protection states that run in the unprivileged state of the processor. User-written application programs typically run in the problem state. (2.) A state during which the processing unit cannot run input/output and other privileged instructions.

procedure. (1.) See shell procedure. (2.) In a programming language, a block, with or without formal parameters, that is initiated by means of a procedure call. (3.) The description of the actions taken to solve a problem. (4.) A set of related control statements that cause one or more programs to be performed. (5.) Synonym for function. (6.) For Ada programming, see subprogram.

procedure address. The location of a particular program procedure in the AIXwindows Toolkit.

process. (1.) A sequence of actions required to produce a desired result. (2.) An entity receiving a portion of the processor's time for running a program. (3.) An activity within the system that is started by a command, a shell program, or another process. When a program is running, it is called a process. (4.) In a computer system, a unique, finite course of events defined by its purpose or by its effect, achieved under given conditions. (5.) Any operation or combination of operations on data. (6.) In the operating system, the current state of a program that is running. This includes a memory image, the program data, variables used, general register values, the status of opened files used, and the current directory. Programs running in a process must be either operating system programs or user programs. See also job.

process accounting. An analysis of how each process uses the processing unit, memory, and I/O resources.

process attribute value. In Workload Management, process attribute values include user ID, group ID, and application pathname.

process concurrency. The degree to which a given process has multiple dispatchable threads at all times.

process group. Each process in the system is a member of a process group that is identified by a process group ID. This grouping permits the signaling of related groups of processes. A newly created process joins the process group of its creator.

process ID (PID). A unique number assigned to a process that is running.

process image. See new-process image.

process lock. Allows the calling process to lock or unlock both its text and data segments into memory.

process pacing. See pacing.

process table. A kernel data structure that contains relevant information about all processes in the system.

processing agent. A thread within an application server that handles remote procedure calls from clients.

processing unit. A functional unit within a computer that is responsible for a certain aspect of processing.

processor affinity. The degree to which a thread is likely to be dispatched to the same physical processor on which it last ran.

product. A software product is made up of software packages that are separately installable.

product ID. An integer that identifies a vendor's licensed software product; by means of product IDs, the license server distinguishes among products of the same vendor.

product password. A string encoded with information about licenses for a software product. Product passwords are of two types: license passwords and compound passwords.

profile. (1.) A file containing customized settings for a system or user. (2.) Data describing the significant features of a user, program, or device. (3.) In security, a description of the characteristics of an entity to which access is controlled. (4.) A description of the control available to a particular network operator. See also customization profile and mapping.

program. (1.) A file containing a set of instructions that conform to a particular programming language syntax. (2.) A sequence of instructions suitable for processing by a computer. Processing can include the use of an assembler, compiler, interpreter, or translator to prepare the program for running, and to run it. (3.) In programming languages, a logical assembly of one or more interrelated modules. In Ada language, a program is composed of a number of compilation units, one of which is a subprogram called the main program. Execution of the program consists of execution of the main program, which may invoke subprograms declared in the other compilation units of the program. (4.) To design, write, and test computer programs.

program assertion. A mathematical statement used in attempts to verify program corrections. In the graphics operating system, the assert subroutine tests program assertions.

program counter. A register in the processing unit that guides the computer through the program. Synonym for instruction address register.

program fault management (PFM). A subsystem of NCS that allows a user to set up cleanup routines when an application does not successfully complete.

Program Initialization Parameters (PIP). Data passed to a program when it starts running. This data modifies the actions taken by that program or the environment in which that program runs.

program level. The version, release, modification, and fix levels of a program. See also fix number, modification number, release number, version, background, and version number.

program stack. Synonym for invocation stack.

program temporary fix (PTF). A temporary solution to, or bypass of, a defect in a current release of a licensed program.

program text. The part of a program that is able to be run. See text.

program-text segment. A virtual-memory segment that contains the executable instructions of an application program. A program-text segment is identified by the occurrence of an instruction-cache miss in that segment.

program unit. A main program or a subprogram. In Ada programming, a program unit is any one of a generic unit, package, subprogram, or task unit. Synonymous with module. See also segment unit.

programmable character set (PCS). A geometric text font. Synonymous with stroke text. See also geometric text.

programmable input/output operation. The transfer of data between the processor and an I/O device or memory address space as part of an I/O instruction. The I/O instruction designates the address of the control logic, the command to be performed and the processor register location into or from which the data is transferred.

programmable terminal. (1.) A user workstation that has computational capabilities. (2.) A workstation that can be programmed to performed user-determined functions.

programmatic interface. In AIXwindows, an application created in such a manner that it will operate in a multiclient environment with other applications running concurrently. Clients communicate with the window manager through Xlib calls or libraries built upon Xlib.

Programmers' Hierarchical Interactive Graphics System (PHIGS). An ANSI and ISO standard. PHIGS defines an application programming interface designed for interactive two-dimensional and three-dimensional graphics applications using retained data structures.

PROM. Programmable read-only memory.

prompt. A displayed symbol or message that requests information or operator action.

propagation time. The time necessary for a signal to travel from one point to another on a communications line.

property. (1.) In Enhanced X-Windows, the name, type, data format, and data associated with a window. By using properties, clients and a window manager share information, such as resize hints, program names, and icon formats. It is a general-purpose naming mechanism for clients. The protocol does not interpret properties. (2.) Public information (that is, information available to any client) that is associated with a window.

property list. In Enhanced X-Windows, the list of properties that are defined for a particular window.

protected. A protected member of a C++ class is accessible to member functions and friends of that class, or member functions and friends of classes derived from that class.

protected field. A displayed field in which a user cannot enter, modify, or erase data.

protection. An arrangement for restricting access to or use of all or part of a computer system.

protection level. The degree to which secure network communications are protected.

protocol. (1.) In SNA and SNA Server, the meaning of, and the sequencing rules for, requests and responses used for managing a network, transferring data, and synchronizing the states of network components. (2.) A set of semantic and syntactic rules that determines the behavior of functional units in achieving communication. (3.) A mutually agreed-upon mechanism for communicating between clients to accomplish certain actions.

protocol boundaries. The set of SNA verbs supported by SNA Server LU6.2.

protocol family. A set of related communications protocols; for example, the Department of Defense Internet Protocols. All members of a protocol family use a common addressing mechanism to identify end points. Synonymous with address family. See also socket address.

protocol port. A unique host identifier used by transport protocols to specify a destination within a host.

prototype file. The first file in a new file system that contains tokens. These include the name of the bootstrap program, the size of the created file system, and the specifications of the root file.

proxy object. In DSOM, a SOM objectin the client's address space that represents a remote object. The proxy object has the same interface as the remote object, but each method invoked on the proxy is overridden by a dispatch method that forwards the invocation request to the remote object. Under DSOM, a proxy object is created dynamically and automatically in the client whenever a remote method returns a pointer to an object that happens to be remote. See also object reference.

pruning. In GL, eliminating the drawing of parts of the display list because a bounding box test shows that they are not visible. See also culling.

P(S). In X.25 communications, the packet send sequence number.

PSAP. See Presentation Service Access Point.

PSDN (packet-switching data network) . A PSDN is an interconnecting set of switching nodes that enables subscribers to exchange data using a standard protocol and packet-switching technology. Such a network carries messages divided into packets over circuits that are shared by many network users. A single physical line into an office can handle many concurrent connections.

pseudo device. A software-based device; for example, a pty device.

Pseudo-PostScript. A graphics language, similar to PostScript, used to drive output of text and graphics.

pseudo terminal (PTY). A special file in the /dev directory that effectively functions as a keyboard and display device to software that uses the Berkeley line discipline. A pseudo terminal consists of a pair of character devices, referred to as the "master" and "slave." The slave device (/dev/pts) is manipulated by another process through the master half (/dev/ptc) of the pseudo terminal.

pseudocolor. In Enhanced X-Windows, (1.) A class of color map in which a pixel value indexes the color map entry to produce independent red, green, and blue values. That is, the color map is viewed as an array of triples (RGB values). The RGB values can be changed dynamically. This is mutually exclusive to the direct color color map class. (2.) Also PseudoColor, a value.

PSN. See public switched network.

PSTN. See public switched telephone network.

PTF. See program temporary fix.

PTN. See public telephone network.

PTT. Post, Telegraph, and Telephone authority.

PTY. See pseudo terminal.

PU. See physical unit.

public. A public member of a C++ class is accessible to all functions.

public data network (PDN). A communications common carrier network providing data communications services over switched or nonswitched lines.

public directory. In BNU, the directory (/var/spool/uucppublic) that is open to all BNU users. The public directory is used to transfer files and programs among systems linked by BNU or other versions of the UNIX-to-UNIX Copy Program (UUCP).

public node. Any node that does not run Monitor system components or servers. For example, client applications run on public nodes.

public switched network (PSN). A communications service through which users can be connected by dialing specific service address numbers.

public switched telephone network (PSTN). A communications common carrier network that provides voice and data communications services over switched lines.

public telephone network (PTN). A communications common carrier network that provides voice and data communications services over switched or nonswitched lines.

puck. A device used to select a particular location on a tablet.

pull installation. In the Network Installation Management environment, an installation that is initiated from a target.

pulldown. The manner in which a MenuPane widget gives the appearance of being "pulled down" from a MenuBar widget as the result of some user action (usually clicking a mouse button).

pulldown menu. A type of MenuPane widget that gives the appearance of being "pulled down" from a MenuBar widget as the result of some user action (usually clicking a mouse button).

pure virtual function. A virtual function is declared pure by replacing the function definition with '=0;'.

purported name. A construct that is syntactically a name, but that has not yet been shown to be a valid name.

push. A term used when a module is inserted in a stream immediately below the stream head.

push button. A rounded-corner rectangle with text inside. Push buttons are used in dialog boxes for actions that occur immediately when the push button is selected.

push installation. In the Network Installation Management environment, an installation that is initiated from a machine other that the target.

push permissions. Permissions that enable remote execution of commands.

pushable module. A module between the stream head and the driver. A driver is a non-pushable module and a stream head includes a non-pushable module.

PUT. Program update tape.

PUT 2.0 or PUT 2.1. In SNA, a peripheral node that has limited addressing and path control routing capabilities. A PUT 2.0 node depends on subarea nodes (PUT 4 and PUT 5) to translate between its local addressing and network addressing. PUT 2.0 does not support the full capabilities of LU6.2; PUT 2.1 does. SNA Server operates only as either a PUT 2.0 or a PUT 2.1 peripheral node.

PUT 4 or PUT 5. A subarea node that provides network-wide addressing and control data flow within a subarea (the subarea node and all peripheral nodes connected to it). PUT 4 does not contain an SSCP component; PUT 5 does. SNA Server cannot perform the functions of a PUT 4 or a PUT 5 subarea node.

PVC. See permanent virtual circuit.

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