Index | A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
| packet: | a component of a message consisting of a sequence of data elements of restricted length together with addressing information |
| packet switch: | a special-purpose computer that is dedicated to the task of sending and receiving data on the behalf of other computers in a WAN |
| packet switching exchange (PSE): | See packet switch. |
| parameter: | a value passed as input to a subroutine |
| parity bit: | a bit which is automatically set or cleared each machine cycle in order to maintain an even number of 1-bits, such that the count of 1-bits in the accumulator plus the parity bit equals an even number; the eighth bit in the PSW register |
| partition: | a subsystem that provides a particular kind of service. A partition may itself be built from lower level subsystems. |
| peer: | two or more system components that are mutually interdependent for services. |
| performance transparency: | a type of transparency that allows the system to be reconfigured to improve performance as loads vary. |
| policy: | the making of context-dependent decisions |
| polymorphic: | "takes on many forms"; the ability of an object to have many identities based on inheritance, interfaces, and overloaded methods; the property that an operation may behave differently on different classes |
| port: | a software-definable destination point for communication within a host computer |
| primary copy model: | a replication model in which all front ends communicate with the same primary server when updating a data item |
| prime number: | an integer whose only factors are 1 and itself |
| principal: | an agent accessing the resources held in a distributed system |
| private member: | a variable or function that can only be accessed from within the same class |
| process: | (in a DFD) something that transforms data values. |
| process group: | a construct that enables a number of concurrent processes to cooperate by sharing a single communication mechanism |
| processor pool model: | a modification of the workstation-server model in which processors can be dynamically allocated to user tasks for the lifetime of the process |
| program counter: | a register in the CPU that serves as a pointer to the next instruction in memory to be executed |
| program status word register (PSW): | the flag register; an 8-bit register which indicates a variety of arithmetic conditions |
| propagation: | the automatic application of an operation to selected objects in a network when the operation is applied to some starting object in the network |
| proper fraction: | a fraction in which the numerator is less than the denominator |
| protected member: | a variable or function that can only be accessed by classes in the same package or by subclasses |
| protocol: | a well-known set of rules and formats to be used for communication; specification of the semantics of an operation |
| protocol layer: | a layer of the network software hierarchy |
| protocol stack: | See protocol suite. |
| protocol suite: | a complete set of protocol layers |
| PSE: | Packet Switching Exchange See packet switch. |
| public member: | a variable or function that can be accessed by all objects |