Packet:-

Any block of data sent over a network. Each packet contains sender, receiver, and error control information, in addition to the actual message. Packets may be fixed- or variable-length, and they will be reassembled if necessary when they reach their destination. The actual format of a packet depends on the protocol that creates the packet; some protocols use special packets to control communications functions in addition to data packets.

Packet Burst Protocol:-

Abbreviated PBP. A Novell NetWare protocol built on top of IPX that speeds up the transfer of multi-packet NetWare Core Protocol (NCP) data transfers between a workstation and a server by removing the need to sequence and acknowledge every packet. Using PBP, a workstation or server can transmit a burst of up to 128 packets before requiring an acknowledgement, thus reducing network traffic.

Packet-switched network:-

A network that consists of a series of Interconnected circuits that route individual packets of data over one of several routes, offering flexibility and high reliability. A packet-switched network may also be called a "cloud" because it contains many different possible connections and routes that a packet might take to reach its destination.

The term often refers to networks using the international standard X.25.

Packet Switching:-

A data-transmission method, that simultaneously routes and transmits data packets from many different customers over a communications channel or telephone line, thus optimizing use of the line. An addressed packet is routed from node to node until it reaches its destination, although related packets may not all follow the same route to that destination. Because long messages may be divided into several packets, packet sequence numbers are used to reassemble the original message at the destination node.

Parallel Communications:-

The transmission of information from computer to computer, or from computer to peripheral device, in which all the bits that make up the character are transmitted at the same time over a multi line cable.

Parallel processing:-

A computing method that can be performed by systems containing two of more processors operating simultaneously. Parallel processing uses several processors, all working on different aspects of the same program at the same time, in order to share the computational load. Parallel processing computers can achieve incredible speeds; the Cray X-MP48 peaks at 1000 million floating-point operations per second (1000 MFLOP) using four extremely powerful processors, while parallel-hypercube systems, first arketed by Intel, can exceed 64,536 processors with speeds of up to 262 billion floating-point operations per second (262 GFLOP).

What is all this speed used for? Applications such as weather forecasting, where the predictive programs can take as long to run as the weather actually takes to arrive, 3-D seismic modeling, groundwater and toxic flow studies, and modeling full-motion dinosaur images used in movies.

Passive Hub:-

A device used in some networks to split a transmission signal, allowing additional hubs to be added to the network, sometimes at the expense of distance.

Password:-

A security method that identifies a specific, authorized user of a computer system or network by a unique string of characters. The user must type these characters to gain access to the computer or network. In general, passwords should be a mixture of letters and numbers, and longer than six characters. Here are some general guidelines:

• Passwords should be kept secret and changed frequently. The worst passwords are the obvious ones: people's names or initials, place names, phone numbers, birth dates, or complete English words. There are a limited number of words in the English language, and it is easy for a computer to try them all relatively quickly.

• Change all passwords every 90 days, and change those associated with high security privileges every month.

• Some systems provide default passwords, such as MANAGER, SERVICE, or GUEST, as part of the installation process. These default passwords should be changed immediately.

• Limit concurrent sessions to one per system.

• Do not allow more than two or three invalid password attempts before disconnecting.

• Do not allow generic accounts.

• Promptly remove the accounts of transferred or terminated people, as well as all unused accounts.

• Review the security log files periodically.

Patch Panel:-

A panel, usually located in a wiring closet that contains rows of telephone-type modular jacks. A patch panel allows to connect, disconnect, move, and test network devices by changing these connections.

PCI local bus:-

Abbreviation for Peripheral component Interconnect local bus. A specification introduced by Intel in 1992 for a local bus that allows up to ten 101 complaint expansion cards to be plugged into the computer. One of these expansion cards must be the PCI controller card, but the others can include a video card, network interface card, SCSI interface, or any other basic function.

The PCI controller exchanges information with the computer's processor, either 32 or 64 bits at a time, and allows intelligent PCI adapters to perform certain tasks concurrently with the main processor by using bus-mastering techniques. PCI is compatible with ISA. EISA, and MCA expansion buses for backward compatibility with older technologies. PCI can operate at a bus speed of 32 MHz, and can manage a maximum throughput of 132 megabytes per second with a 32-bit data path, or a rate of 264 megabytes per second with a 64-Dit data path.

PDA:-

Abbreviation for personal digital assistant. A tiny, penbased, battery-powered palmtop computer that combines personal organization software with fax and e-mail facilities into a unit that fits into your pocket. PDAs are available from several manufacturers, including Apple's Newton, and others from Casio, Tandy, Toshiba, Motorola, Sharp, Sony, GRiD, and AT&T.

Peer-to-Peer:-

A network architecture in which two or more nodes can communicate with each other directly, without the need for any intermediary devices. In a peer-to-peer system, a node can be both a client and a server.

Peer-to-Peer:-

A local area network in which drives, files, and printers on each PC can be available to every other PC on the network, eliminating the need for a dedicated file server. Each PC can still run local applications. Peer-to-peer networks introduce their own system management problems, including administration and responsibility for system backup, reliability and security. Peer-to -peer systems are often used in relatively small networks, with two to ten users, and can be based on DOS, OS/2, or UNIX. Popular peer-to-peer network operating systems include Novell's Personal NetWare, Artisoft's LANtastic, and PowerLAN from Performance Technology.

Personal Information Manager:-

Abbreviated PIM. A multipurpose software package that combines a word processor, databases, and other accessory modules to allow the user to manipulate data in a less structured way than required by conventional programs. A PIM can store notes, memos, names and addresses, appointments, and to-do lists, and it may be part of the software used in a PDA (personal digital assistant).

Personal NetWare:-

 Novell's peer-to-peer network replacement for NetWare Lite, released in 1994, that provides DOS and Microsoft Windows users with the ability to share files, printers, CD-ROMs, and other resources, as well as run standard network applications. Other features include simplified network administration, increased security, and a single login so that users can view or access all network resources at once. Personal NetWare can manage up to fifty workstations per server and up to fifty servers on each network, giving a aximum of 2500 nodes per network.

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