PPP- Stands for Point To Point Protocol. It's a software application that allows an attachment to a server.
Parallel Port- A parallel interface for connecting an external device such as a printer. Most personal computers have both a parallel port and at least one serial port. On PCs, the parallel port uses a 25-pin connector (type DB-25) and is used to connect printers, computers and other devices that need relatively high bandwidth. It is often called a Centronics interface after the company that designed the original standard for parallel communication between a computer and printer. (The modern parallel interface is based on a design by Epson.)
A newer type of parallel port, which supports the same connectors as the Centronics interface, is the EPP (Enhanced Parallel Port) or ECP (Extended Capabilities Port). Both of these parallel ports support bi-directional communication and transfer rates ten times as fast as the Centronics port.
Macintoshes have a SCSI port, which is parallel, but more flexible.
Partition- A portion of a hard disk that functions as a separate unit. A single hard disk can be divided into several partitions, each of which functions as a separate drive and has its own volume name (such as D:, E:, F:, and so on). The purpose is to make the drive more efficient, as the computer can search smaller sections for a specific file rather than the entire drive. The verb to partition refers to the process of dividing the hard drive into partitions.
Path- A path can be described as a file's address on your file system, describing where the file lives: An absolute path gives the complete path, starting at the root directory, or the very top of the file system; A relative path looks for a file from the directory you are currently in down.
PCI- Acronym for Peripheral Component Interconnect, a local bus standard developed by Intel Corporation. Most modern PCs include a PCI bus in addition to a more general ISA expansion bus. Many analysts, however, believe that PCI will eventually supplant ISA entirely. PCI is also used on newer versions of the Macintosh computer.
PCI is a 64-bit bus, though it is usually implemented as a 32-bit bus. It can run at clock speeds of 33 or 66 MHz. At 32 bits and 33 MHz, it yields a throughput rate of 133 MBps.
Although it was developed by Intel, PCI is not tied to any particular family of microprocessors.
Peer to Peer - A type of network in which each workstation has equivalent capabilities and responsibilities. This differs from client/server architectures, in which some computers are dedicated to serving the others. Peer-to-peer networks are generally simpler and less expensive, but they usually do not offer the same performance under heavy loads.
Pen drive- A small keyring-sized device that can be used to easily transfer files between USB-compatible systems. Available in a range of capacities (and in some cases, with an MP3 player built-in). Plug it in to any USB port and it will be automatically detected by the Operating System.
Peripheral- Any external device attached to a computer. Examples of peripherals include printers, disk drives, display monitors, keyboards, and mice.
PGA- Short for Pin Grid Array, a type of chip package in which the connecting pins are located on the bottom in concentric squares. PGA chips are particularly good for chips that have many pins, such as modern microprocessors. Compare with DIP and SIP.
Short for Professional Graphics Adapter, a video standard developed by IBM that supports 640x480 resolution
Phishing- Short for Password Harvesting Fishing. It is the luring of sensitive information, such as passwords and other personal information, from a victim by masquerading as someone trustworthy with a real need for such information.
Popular targets are users of online banking services, and auction sites such as eBay. Phishers usually work by sending out spam e-mail to large numbers of potential victims. Typically the email will appear to come from a trustworthy company and contain a subject and message intended to alarm the recipient into taking action.
A common approach is to tell the recipient that their account has been de-activated due to a problem and inform them that they must take action to re-activate their account. The user is provided with a convenient link in the same email that takes the email recipient to a fake web page appearing to be that of a trustworthy company. Once at that page, the user enters her personal information which is then captured by the fraudster.
PHP- (Hypertext Preprocessor) is a server-side, HTML-embedded scripting language used to create dynamic Web pages. In an HTML document, PHP script (similar syntax to that of Perl or C) is enclosed within special PHP tags. Because PHP is embedded within tags, the author can jump between HTML and PHP (similar to ASP and Cold Fusion) instead of having to rely on heavy amounts of code to output HTML. Because PHP is executed on the server, the client cannot view the PHP code. PHP can perform any task any CGI program can, but its strength lies in its compatibility with many types of databases. Also, PHP can talk across networks using IMAP, SNMP, NNTP, POP3 or HTTP.
PICT- Pronounced "Pick,t." It is another image format.
PING- Packet Internet or Inter-Network Groper; a utility used to determine whether a particular computer is currently connected to the Internet. It works by sending a packet to the specified IP address and waiting for a reply. The computer acronym "PING" was contrived to match the submariners' term for the sound of a returned sonar pulse.
Pinout- A diagram or table that describes the purpose of each pin in a chip or connector, or each wire in a cable.
PIO- (Programmed Input/Output) A method of data transfer in which the host microprocessor transfers data to and from memory via the computer's I/O ports. PIO enables very fast data transfer rates, especially in single-tasking operating systems like DOS.
Pipeline Burst Cache- A type of memory cache built into many modern DRAM controller and chipset designs. Pipeline burst caches use two techniques - a burst mode that pre-fetches memory contents before they are requested, and pipelining so that one memory value can be accessed in the cache at the same time that another memory value is accessed in DRAM. The purpose of pipeline burst caches is to minimize wait states so that memory can be accessed as fast a possible by the microprocessor.
Pixel- Short for Picture Element, a pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousands (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected.
The number of bits used to represent each pixel determines how many colors or shades of gray can be displayed. For example, in 8-bit color mode, the color monitor uses 8 bits for each pixel, making it possible to display 2 to the 8th power (256) different colors or shades of gray.
On color monitors, each pixel is actually composed of three dots -- a red, a blue, and a green one. Ideally, the three dots should all converge at the same point, but all monitors have some convergence error that can make color pixels appear fuzzy.
The quality of a display system largely depends on its resolution, how many pixels it can display, and how many bits are used to represent each pixel. VGA systems display 640 by 480, or about 300,000 pixels. In contrast, SVGA systems display 1,024 by 768, or nearly 800,000 pixels. True Color systems use 24 bits per pixel, allowing them to display more than 16 million different colors.
Platform- A combination of hardware and operating system you use, for example, the "NT platform" is a PC running the Microsoft Windows NT operating system and the "PPC platform" is a Macintosh computer with a PowerPC processor running the Mac operating system.
PLD- ((Programmable Logic Device) A digital integrated circuit that can be programmed by the user to perform a wide variety of logical operations.
Plotter- A computer output device that draws images on paper using a pen. A plotter draws real lines rather than simulating them as a conventional printer would by producing a series of very close dots.
Plug-In- This is a program that your browser uses to manipulate a downloaded file. It differs from a Helper Application in that the plug-in works inside the browser window.
PNP- Short for Plug and Play, a technology developed by Microsoft and Intel that supports plug-and-play installation. PnP is built into the Windows 95 operating system, but to use it, the computer's BIOS and expansion boards must also support PnP.
Port- This is the connecting component or hardware that allows two computers to attach to one another.
Portal- A web site that aims to be an entry point to the World-Wide Web, typically offering a search engine and/or links to useful pages, and possibly news or other services. These services are usually provided for free in the hope that users will make the site their default home page or at least visit it often. Popular examples are Yahoo and MSN. Most portals on the Internet exist to generate advertising income for their owners, others may be focused on a specific group of users and may be part of an intranet or extranet. Some may just concentrate on one particular subject, say technology or medicine, and are known as a vertical portals.
Post- Short for power-on self test, a series of diagnostic tests that run automatically when you turn your computer on. The actual tests can differ depending on how the BIOS is configured, but usually the POST tests the RAM, the keyboard, and the disk drives. If the tests are successful, the computer boots itself. If the tests are unsuccessful, the computer reports the error by emitting a series of beeps and possibly displaying an error message and code on the display screen. The number of beeps indicates the error, but differs from one BIOS to another.
POP- Point of Presence, also Post Office Protocol
Two commonly used meanings:
A Point of Presence usually means a city or location where a network can be connected to, often with dial up phone lines. So if an Internet company says they will soon have a POP in Belgrade, it means that they will soon have a local phone number in Belgrade and/or a place where leased lines can connect to their network.
A second meaning, Post Office Protocol refers to a way that e-mail client software, such as Outlook, gets mail from a mail server. When you obtain an account from an Internet Service Provider (ISP) you almost always get a POP account with it, and it is this POP account that you tell your e-mail software to use to get your mail. Another protocol called IMAP is replacing POP for email.
Primary Cache- Primary cache is the cache located closest to the CPU. Usually, primary cache is internal to the CPU, and secondary cache is external. Some early-model personal computers have CPU chips that don't contain internal cache. In these cases the external cache, if present, would actually be the primary (L1) cache.
Processor- A processor is a device that processes programmed instructions and performs tasks. Your processor sends and receives information from the different parts of the system (from hardware and software). The speed at which the CPU processes information internally is measured in MegaHertz (MHz) and GigaHertz (GHz). 1 GHz is equal to 1,000 MHz.
Protocol- An agreed-upon format for transmitting data between two devices. The protocol determines the following:
- The type of error checking to be used.
- Data compression method, if any.
- How the sending device will indicate that it has finished sending a message.
- How the receiving device will indicate that it has received a message.
There are a variety of standard protocols from which programmers can choose. Each has particular advantages and disadvantages; for example, some are simpler than others, some are more reliable, and some are faster. From a user's point of view, the only interesting aspect about protocols is that your computer or device must support the right ones if you want to communicate with other computers. The protocol can be implemented either in hardware or in software.
Proxy Server- A server that acts as an intermediary between a workstation user and the internet so that the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with, or part of, a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from the outside intrusion.
PS/2 Port- A type of port developed by IBM for connecting a mouse or keyboard to a PC. The PS/2 port supports a mini DIN plug containing just 6 pins. Most PCs have a PS/2 port so that the serial port can be used by another device, such as a modem. The PS/2 port is often called the mouse port.
QAM- Quadrature Amplitude Modulation. A method of modulating digital signals using both amplitude and phase coding. Used for downstream and can be used for upstream.
QPSK- Quadrature Phase-Shift Keying. A method of modulating digital signals using four phase states to code two digital bits per phase shift.
Query- This is to make a computer request of a database.
RAID- Short for Redundant Array of Independent (or Inexpensive) Disks, a category of disk drives that employ two or more drives in combination for fault tolerance and performance. RAID disk drives are used frequently on servers but aren't generally necessary for personal computers.
There are number of different RAID levels. The three most common are 0, 3, and 5:
Level 0: Provides data striping (spreading out blocks of each file across multiple disks) but no redundancy. This improves performance but does not deliver fault tolerance.
Level 1: Provides disk mirroring.
Level 3: Same as Level 0, but also reserves one dedicated disk for error correction data. It provides good performance and some level of fault tolerance.
Level 5: Provides data striping at the byte level and also stripe error correction information. This results in excellent performance and good fault tolerance.
RAM- (Random Access Memory) A configuration of memory cells that hold data for processing by a computer's central processing unit, or CPU; (see also memory). The term random derives from the fact that the CPU can retrieve data from any individual location, or address, within RAM.
Ranging- The process of automatically adjusting transmit levels and time offsets of individual modems, in order to make sure the bursts coming from different modems line up in the right timeslots and are received at the same power level at the CMTS.
RAS- Short for Remote Access Services, a feature built into Windows NT that enables users to log into an NT-based LAN using a modem, X.25 connection or WAN link. RAS works with several major network protocols, including TCP/IP, IPX, and Netbeui.
To use RAS from a remote node, you need a RAS client program, which is built into most versions of Windows, or any PPP client software. For example, most remote control programs work with RAS.
RDRAM- Rambus DRAM technology is a system-wide, chip-to-chip interface design that allows data to pass through a simplified bus. Rambus uses a unique RSL (Rambus Signaling Logic) technology. Rambus is available in two flavors: RDRAM and Concurrent RDRAM. RDRAM is currently in production with Concurrent RDRAM production scheduled for late 1997. The third line extension, Direct RDRAM, is in development stages and scheduled for production in 1999. In late 1996, Rambus agreed to a development and license contract with Intel that will lead to Intel's PC chip sets supporting Rambus memory starting in 1999.
RealAudio- SThis is a method of playing sounds invented by Rob Glasser that creates a buffer between the supplying server and your computer. The file is played without downloading it completely.
Real Time- TThis is method of processing data the moment it is received. Batch mode is a term used for a mainframe computer dealing with data when it has the time.
Reboot- To restart a computer. In DOS, you can reboot by pressing the Alt, Control and Delete keys simultaneously. This is called a warm boot. You can also perform a cold boot by turning the computer off and then on again.
On Macs, you reboot by selecting the "Restart" option from the Special menu.
Redundant- Array of Inexpensive (or Interconnected) Disks. A performance enhancing method of storing the same data in different places on multiple hard disks. Unnecessary redundancy can cause problems if one copy of the data is updated and another copy of the data is not. All redundant data can't be eliminated in most databases because primary keys in one table are repeated in other tables as foreign keys to create links between tables. This type of redundancy is called controlled redundancy.
Refresh- Generally, to update something with new data. For example, some Web browsers include a refresh button that updates the currently display Web pages. This feature is also called reload.
To recharge a device with power or information. For example, dynamic RAM needs to be refreshed thousands of times per second or it will lose the data stored in it.
Similarly, display monitors must be refreshed many times per second. The refresh rate for a monitor is measured in hertz (Hz) and is also called the vertical frequency, vertical scan rate, frame rate or vertical refresh rate. The old standard for monitor refresh rates was 60Hz, but a new standard developed by VESA sets the refresh rate at 75Hz for monitors displaying resolutions of 640x480 or greater. This means that the monitor redraws the display 75 times per second. The faster the refresh rate, the less the monitor flickers.
Resolution- Refers to the sharpness and clarity of an image. The term is most often used to describe monitors, printers, and bit-mapped graphic images. In the case of dot-matrix and laser printers, the resolution indicates the number of dots per inch. For example, a 300-dpi (dots per inch) printer is one that is capable of printing 300 distinct dots in a line 1 inch long. This means it can print 90,000 dots per square inch.
For graphics monitors, the screen resolution signifies the number of dots (pixels) on the entire screen. For example, a 640-by-480 pixel screen is capable of displaying 640 distinct dots on each of 480 lines, or about 300,000 pixels. This translates into different dpi measurements depending on the size of the screen. For example, a 15-inch VGA monitor (640x480) displays about 50 dots per inch.
Printers, monitors, scanners, and other I/O devices are often classified as high resolution, medium resolution, or low resolution. The actual resolution ranges for each of these grades is constantly shifting as the technology improves.
Resource- Generally, any item that can be used. Devices such as printers and disk drives are resources, as is memory.
In many operating systems, including Microsoft Windows and the Macintosh operating system, the term resource refers specifically to data or routines that are available to programs. These are also called system resources.
RFID- Radio Frequency identification (ID). Refers to the technology that uses devices attached to objects that transmit data to an RFID receiver. An alternative to bar coding. Advantages include data capacity, read/write capability, and no line-of-sight requirements.
RISC- Reduced Instruction Set Computer. A computer processing architecture that requires fewer instructions to run applications, thus increasing processing speed.
RFID- Radio Frequency identification (ID). Refers to the technology that uses devices attached to objects that transmit data to an RFID receiver. An alternative to bar coding. Advantages include data capacity, read/write capability, and no line-of-sight requirements.
RJ-11- Short for Registered Jack-11, a four- or six-wire connector used primarily to connect telephone equipment in the United States. RJ-11 connectors are also used to connect some types of local-area networks (LANs), although RJ-45 connectors are more common.
RJ-45- Short for Registered Jack-45, an eight-wire connector used commonly to connect computers onto a local-area networks (LAN), especially Ethernets. RJ-45 connectors look similar to the ubiquitous RJ-11 connectors used for connecting telephone equipment, but they are somewhat wider.
ROM- Stands for Read-Only Memory. A semiconductor-based memory system that stores information permanently and does not lose its contents when power is switched off. ROMs are used for firmware, such as the BIOS used in the PC; and in some portable computers, application programs and even the operating system are being stored in ROM.
Router- A device that connects any number of LANs. Routers use headers and a forwarding table to determine where packets go, and they use ICMP to communicate with each other and configure the best route between any two hosts. Very little filtering of data is done through routers. Routers do not care about the type of data they handle.
Routing Switch- A switch that also performs routing operations. Usually a switch operates at layer 2 (the Data Link layer) of the OSI Reference Model while routers operate at layer 3 (the Network layer). Routing switches, however, perform many of the layer 3 functions usually reserved for routers. And because the routing is implemented in hardware rather than software, it is faster. The downside of routing switches is that they are not as powerful or as flexible as full-fledged routers.
Because they perform some layer 3 functions, routing switches are sometimes called layer-3 switches.
RPL- Request Parameter List. A VTAM (Virtual Telecommunications Access Method) control block that contains parameters necessary for processing a request (data transfer, connecting or disconnecting a terminal, etc).
Also, Relocatable Program Library. A data set used to store CICS (Customer Information Control System) application programs, which are fetched (loaded) at execution time.
RSS: (Rich Site Summary) - XML format for distributing news headlines on the Web, also known as Really Simple Syndication.
Scalable- A system or architecture is scalable when it can be changed in size or configuration to suit changing conditions. For example, a company that plans to set up a client/server network may want to have a system that not only works with the number of people who will immediately use the system, but the number who may be using it in one year, five years, or ten years.
Scalar Processing- A sequential operation in which one instruction produces one result; it starts an instruction, handles one operand or operand pair, and produces one result. Scalar processing complements vector processing by providing solutions to problems not readily adaptable to vector techniques.
Screen Flicker- The phenomenon whereby a display screen appears to flicker. Screen flicker results from a variety of factors, the most important of which is the monitor's refresh rate, the speed with which the screen is redrawn. If the refresh rate is too slow, the screen will appear to glimmer. Another factor that affects screen flicker is the persistence of the screen phosphors. Low-persistence phosphors fade more quickly than high-persistence monitors, making screen flicker more likely. Screen flicker can also be affected by lighting. Finally, screen flicker is a subjective perception that affects people differently. Some people perceive screen flicker where others do not. Most people perceive no screen flicker if the refresh rate is 72 MHz or higher.
SCSI- Abbreviation of Small Computer System Interface. Pronounced "scuzzy," SCSI is a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. Nearly all Apple Macintosh computers, excluding only the earliest Macs and the recent iMac, come with a SCSI port for attaching devices such as disk drives and printers.
SCSI interfaces provide for faster data transmission rates (up to 80 megabytes per second) than standard serial and parallel ports. In addition, you can attach many devices to a single SCSI port, so that SCSI is really an I/O bus rather than simply an interface.
The following varieties of SCSI are currently implemented:
- SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps
- SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a 25-pin connector, and supports multiple devices. This is what most people mean when they refer to plain SCSI.
- Wide SCSI: Uses a wider cable (168 cable lines to 68 pins) to support 16-bit transfers.
- Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data rates of 10 MBps.
- Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps.
- Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps.
- SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called Ultra Wide SCSI.
- Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps.
- Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps.
SDH- Synchronous Digital Hierarchy. A method used for multiplexing many circuits with a low bit rate onto fewer circuits with a higher bit rate, and vice-versa (de-multiplexing). Used primarily in the telecomms industry to carry telephony traffic. This network can also be used to carry IP traffic.
SDRAm- Short for Synchronous Dynamic Random Access Memory, a new type of DRAM that can run at much higher clock speeds than conventional memory. SDRAM actually synchronizes itself with the CPU's bus and is capable of running at 100 MHz, about three times faster than conventional FPM RAM, and about twice as fast EDO DRAM and BEDO DRAM. SDRAM is replacing EDO DRAM in many newer computers.
Today's fastest Pentium systems use CPU buses running at 100 MHz, so SDRAM can keep up with them, though barely. Future PCs, however, are expected to have CPU buses running at 200 MHz or faster. SDRAM is not expected to support these high speeds which is why new memory technologies, such as RDRAM and SLDRAM, are being developed.
Secondary Cache- Short for Level 2 cache, cache memory that is external to the microprocessor. In general, L2 cache memory, also called the secondary cache, resides on a separate chip from the microprocessor chip. The Pentium Pro, however, has an L2 cache on the same chip as the microprocessor.
Semiconductor- A material that is neither a good conductor of electricity (like copper) nor a good insulator (like rubber). The most common semiconductor materials are silicon and germanium. These materials are then doped to create an excess or lack of electrons.
Computer chips, both for CPU and memory, are composed of semiconductor materials. Semiconductors make it possible to miniaturize electronic components, such as transistors. Not only does miniaturization mean that the components take up less space, it also means that they are faster and require less energy.
SEO- (Search Engine Optimization) SEO is a process of arranging a web site's content to obtain high rankings in various search engines (both the site and individual pages), and includes tailoring on-page text (such as headlines and subtitles) as well as choosing the proper keywords for a page's meta tags.
Serial Port- A port, or interface, that can be used for serial communication, in which only 1 bit is transmitted at a time. Most serial ports on personal computers conform to the RS-232C or RS-422 standards. A serial port is a general-purpose interface that can be used for almost any type of device, including modems, mice, and printers (although most printers are connected to a parallel port).
Server- This is a mainframe computer that serves the other computers attached to it.
SGRAM- Abbreviation of Synchronous Graphic Random Access Memory, a type of DRAM used increasingly on video adapters and graphics accelerators. Like SDRAM, SGRAM can synchronize itself with the CPU bus clock up to speeds of 100 MHz. In addition, SGRAM uses several other techniques, such as masked writes and block writes, to increase bandwidth for graphics-intensive functions.
Unlike VRAM and WRAM, SGRAM is single-ported. However, it can open two memory pages at once, which simulates the dual-port nature of other video RAM technologies.
Shadowing- A technique used to increase a computer's speed by using high-speed RAM memory in place of slower ROM memory (RAM is about three times as fast as ROM). On PCs, for example, all code to control hardware devices, such as keyboards, is normally executed in a special ROM chip called the BIOS ROM. However, this chip is slower than the general-purpose RAM that comprises main memory. Many PC manufacturers, therefore, configure their PCs to copy the BIOS code into RAM when the computer boots. The RAM used to hold the BIOS code is called shadow RAM.
Shareware - Software distributed on the basis of an honor system. Most shareware is delivered free of charge, but the author usually requests that you pay a small fee if you like the program and use it regularly. By sending the small fee, you become registered with the producer so that you can receive service assistance and updates. You can copy shareware and pass it along to friends and colleagues, but they too are expected to pay a fee if they use the product.
Shareware is inexpensive because it is usually produced by a single programmer and is offered directly to customers. Thus, there are practically no packaging or advertising expenses.
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Shell
The outermost layer of a program. Shell is another term for user interface. Operating systems and applications sometimes provide an alternative shell to make interaction with the program easier. For example, if the application is usually command driven, the shell might be a menu-driven system that translates the user's selections into the appropriate commands.
Sometimes called command shell, a shell is the command processor interface. The command processor is the program that executes operating system commands. The shell, therefore, is the part of the command processor that accepts commands. After verifying that the commands are valid, the shell sends them to another part of the command processor to be executed.
SID (Service ID)- Used in the DOCSIS standard to defines a particular mapping between a cable modem (CM) and the CMTS. The SID is used for the purpose of upstream bandwidth allocation and class-of-service management.
SIMM- Acronym for single in-line memory module, a small circuit board that can hold a group of memory chips. Typically, SIMMs hold up 8 (on Macintoshes) or 9 (on PCs) RAM chips. On PCs, the ninth chip is often used for parity error checking. Unlike memory chips, SIMMs are measured in bytes rather than bits. SIMMs are easier to install than individual memory chips.
The bus from a SIMM to the actual memory chips is 32 bits wide. A newer technology, called dual in-line memory module (DIMM), provides a 64-bit bus. For modern Pentium microprocessors that have a 64-bit bus, you must use either DIMMs or pairs of SIMMs.
SIP - Abbreviation of single in-line package, a type of housing for electronic components in which the connecting pins protrude from one side. Compare with DIP and PGA. A SIP is also called a Single In-line Pin Package (SIPP).
Socket- In UNIX and some other operating systems, a software object that connects an application to a network protocol. In UNIX, for example, a program can send and receive TCP/IP messages by opening a socket and reading and writing data to and from the socket. This simplifies program development because the programmer need only worry about manipulating the socket and can rely on the operating system to actually transport messages across the network correctly. Note that a socket in this sense is completely soft - it's a software object, not a physical component.
A receptacle into which a plug can be inserted
A receptacle for a microprocessor or other hardware component.
Socket 7- The form factor for fifth-generation CPU chips from Intel, Cyrix, and AMD. All Pentium chips, except Intel's Pentium Pro (Socket 8) and Pentium II (Slot 1), conform to the Socket 7 specifications. Intel has decided to phase out Socket 7 and replace it with Slot 1. But Intel's competitors, such as AMD and Cyrix, are sticking with Socket 7, and are developing an enhanced version.
Socket 8- The form factor for Intel's Pentium Pro microprocessors. The Pentium Pro was the first microprocessor not to use the venerable Socket 7 form factor. The Pentium II microprocessors use an even newer form factor called Slot 1. Socket 8 is a 387-pin ZIF socket with connections for the CPU and one or two SRAM dies for the Level 2 (L2) cache.
Software Modem- A modem implemented entirely in software. Software modems rely on the computer's processor to modulate and demodulate signals.
Source Code- Computer programs or operating systems are originally written by a human being in a programming language. This is called the source code of the software. To be actually used by a computer, the program has to be translated by the computer from the source code into the machine language that the computer understands and can execute. This translation process is referred to as compiling.
SLIP- Stands for Serial Line Interface Protocol. This is another application that allows for a connection to another computer.
SMTP- Stands for Simple Mail Transfer Protocol.
SNMP- Since it was developed in 1988, the Simple Network Management Protocol has become the de facto standard for Internet work management. Because it is a simple solution, requiring little code to implement, vendors can easily build SNMP agents to their products. SNMP is extensible, allowing vendors to easily add network management functions to their existing products. SNMP also separates the management architecture from the architecture of the hardware devices, which broadens the base of multi-vendor support. Perhaps most important, unlike other so-called standards, SNMP is not a mere paper specification, but an implementation that is widely available today.
Software- This is a program, the actual code the computer reads. All other stuff is hardware. A floppy disc is hardware.
Spoofing- To fool. In networking, the term is used to describe a variety of ways in which hardware and software can be fooled. Email spoofing, for example, involves trickery that makes a message appear as if it came from a legitimate business email address.
SQL- X(Structured Query Language) A specialized programming language for sending queries to databases. Most industrial-strength and many smaller database applications can be addressed using SQL. Each specific application will have its own version of SQL implementing features unique to that application, but all SQL-capable database support a common subset of SQL.
SRAM- Short for static random access memory, and pronounced ess-ram. SRAM is a type of memory that is faster and more reliable than the more common DRAM (dynamic RAM). The term static is derived from the fact that it doesn't need to be refreshed like dynamic RAM.
While DRAM supports access times of about 60 nanoseconds, SRAM can give access times as low as 10 nanoseconds. In addition, its cycle time is much shorter than that of DRAM because it does not need to pause between accesses. Unfortunately, it is also much more expensive to produce than DRAM. Due to its high cost, SRAM is often used only as a memory cache.
SSL: (Secure Sockets Layer)- A protocol designed by Netscape Communications to enable encrypted, authenticated communications across the Internet. SSL is used mostly in communications between Web browsers and Web servers. URLs that begin with "https" indicate that an SSL connection will be used.
Subroutine- A procedure that performs a specific function; usually a process that may be needed several times or a routine that may be used in several different programs. For example, many subroutines have been created to parse URL-encoded data.
Subscriber Unit (SU)- An alternate term for cable modem.
SVGA - Stands for Super Video Graphics Adapter. It's a high level monitor.
Swap File- A swap file is an area on your hard disk used as virtual memory. It's called a swap file because virtual memory management software swaps data between it and main memory (RAM).
Swap Space- Disk space used by the kernel as "virtual" RAM. It is slower than RAM, but because disk space is cheaper, swap is usually more plentiful. Swap space is useful to the kernel for holding lesser-used data and as a fallback when physical RAM is exhausted.
Switch- In networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.
A small lever or button. The switches on the back of printers and on expansion boards are called DIP switches. A switch that has just two positions is called a toggle switch.
Another word for option or parameter -- a symbol that you add to a command to modify the command's behavior.
Switching Hub- Short for port-switching hub, a special type of hub that forwards packets to the appropriate port based on the packet's address. Conventional hubs simply rebroadcast every packet to every port. Since switching hubs forward each packet only to the required port, they provide much better performance. Most switching hubs also support load balancing, so that ports are dynamically reassigned to different LAN segments based on traffic patterns.
Some newer switching hubs support both traditional Ethernet (10 Mbps) and Fast Ethernet (100 Mbps) ports. This enables the administrator to establish a dedicated, Fast Ethernet channel for high-traffic devices such as servers.
Synchronous- Synchronous can refer to: (1) A communications method that transmits a group of characters as a block of data rather than as individual characters. (2) A reference to the fact that two different data streams are tied, or synchronized, to a single reference clock. (3) Data transmitted in a time-division multiplexer.
Source: "The Free On-line Dictionary of Computing, http://www.foldoc.org/, Editor Denis Howe"
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Network Technologies