Access Control List- (ACL) A list of the services available on a
server, each with a list of the hosts permitted to use the
service.
Anonymous FTP- An interactive service provided by many
Internet hosts allowing any user to transfer documents,
files, programs, and other archived data using File Transfer
Protocol. The user logs in using the special user name
"ftp" or "anonymous" and his e-mail address as password.
He then has access to a special directory hierarchy containing
the publically accessible files, typically in a subdirectory
called "pub". This is usually a separate area from files used
by local users.
A reference like
ftp: euagate.eua.ericsson.se /pub/eua/erlang/info
means that files are available by anonymous FTP from the host
called euagate.eua.ericsson.se in the directory (or file)
/pub/eua/erlang/info. Sometimes the hostname will be
followed by an Internet address in parentheses. The
directory will usually be given as a path relative to the
anonymous FTP login directory. A reference to a file
available by FTP may also be in the form of a URL starting
"ftp:".
Application Layer- The top layer of the OSI seven layer model.
This layer handles issues like network transparency,
resource allocation and problem partitioning. The application
layer is concerned with the user's view of the network
(e.g. formatting electronic mail messages). The
presentation layer provides the application layer with a
familiar local representation of data independent of the
format used on the network.
Access Point- A hardware device or a computer's software that acts as a communication hub for users of a wireless device to connect to a wired LAN
AI- Stands for Artificial Intelligence. This is the area of computer science focusing on creating machines that can engage on behaviors that humans consider intelligent. The ability to create intelligent machines has intrigued humans since ancient times, and today with the advent of the computer and 50 years of research into AI programming techniques, the dream of smart machines is becoming a reality. Researchers are creating systems which can mimic human thought, understand speech, beat the best human chess player, and countless other feats never before possible.
ACPI- A hardware device or a computer's software that acts as a communication hub for users of a wireless device to connect to a wired LAN
Access Point- A hardware device or a computer's software that acts as a communication hub for users of a wireless device to connect to a wired LAN
Actuator- Device that performs an action or outputs a signal in response to a signal from a computer.
Addressing- A method of identifying a resource (such as a program) or piece of information (such as a file) on a network. Methods of addressing vary considerably from network-to-network.
AGP- Short for Accelerated Graphics Port, a new interface specification developed by Intel Corporation. AGP is based on PCI, but is designed especially for the throughput demands of 3-D graphics. Rather than using the PCI bus for graphics data, AGP introduces a dedicated point-to-point channel so that the graphics controller can directly access main memory. The AGP channel is 32 bits wide and runs at 66 MHz. This translates into a total bandwidth of 266 MBps, as opposed to the PCI bandwidth of 133 MBps. AGP also supports two optional faster modes, with throughputs of 533 MBps and 1.07 GBps. In addition, AGP allows 3-D textures to be stored in main memory rather than video memory.
AGTL Signaling- (Assisted Gunning Transistor Logic) AGTL and AGTL+ use the same signaling protocol only at different voltage levels. AGTL+ operates at 1.5V signaling levels, while AGTL operates at 1.25V.
Algorithm- A formal set of instructions that can be followed to perform a specific task, such as a mathematical formula or a set of instructions in a computer program.
AMD- (Advanced Microchip Devices) A semiconductor manufacturer and is a major competitor of Intel. They manufacture the Athlon, Duron, and K6 CPU chips
ANSI- It stands for American National Standards Institute. The Institute's mission is to enhance both the global competitiveness of U.S. business and the U.S. quality of life by promoting and facilitating voluntary consensus standards and conformity assessment systems, and safeguarding their integrity.
AppleTalk- A protocol suite developed by Apple Computer in the early 1980s, was developed in conjunction with the Macintosh computer. AppleTalk's purpose was to allow multiple users to share resources, such as files and printers. The devices that supply these resources are called servers, while the devices that make use of these resources (such as a user's Macintosh computer) are referred to as clients. Hence, AppleTalk is one of the early implementations of a distributed client/server networking system.
AppleScript- It is an English-like language used to write script files which can automate the actions of the computer and the applications which run on it.
AppleShare- This is Apple's network system. It is to the Macintosh what FTP is to the PC.
Applet- An applet is a small program, generally written in the Java programming language that is usually translated by browsers thus allowing interactivity on Web pages.
Application- A software program designed to perform a specific task or group of tasks, such as word processing, communications, or database management.
Archie- Or ArchiePlex which is an Archie gateway for the World Wide Web. It can locate files on Anonymous FTP sites in the Internet.
ASCII- It stands for American Standard Code Information Exchange and is pronounced (ask-ee). A standard code or protocol for displaying characters and transferring data between computers and associated equipment. It was developed for the purpose of information exchange among the following:
- Associated equipment
- Data communications systems
- Data processing systems
There are 128 standard ASCII codes each of which can be represented by a 7 digit binary number: 0000000 through 1111111.
Asynchronous- 1 : not synchronous; not occurring or existing at the same time or having the same period or phase.
2 : of, used in, or being digital communication (as between computers) in which there is no timing requirement for transmission and in which the start of each character is individually signaled by the transmitting device.
ASP- Stands for Active Server Pages, which is an open, compile-free application environment in which you can combine HTML, scripts, and reusable ActiveX server components to create dynamic and powerful Web-based business solutions. Active Server Pages enables server side scripting for IIS with native support for both VBScript and Jscript.
ATA- Short for Advanced Technology Attachment, a disk drive implementation that integrates the controller on the disk drive itself. There are several versions of ATA, all developed by the Small Form Factor (SFF) Committee:
- ATA: Known also as IDE, supports one or two hard drives, a 16-bit interface and PIO modes 0, 1 and 2.
- ATA-2: Supports faster PIO modes (3 and 4) and multiword DMA modes (1 and 2). Also supports logical block addressing (LBA) and block transfers. ATA-2 is marketed as Fast ATA and Enhanced IDE (EIDE).
- ATA-3: Minor revision to ATA-2.
- Ultra-ATA: Also called Ultra-DMA, ATA-33, and DMA-33, supports multiword DMA mode 3 running at 33 MBps.
- ATA/66: A version of ATA proposed by Quantum Corporation, and supported by Intel, that doubles ATA's throughput to 66 MBps.
- ATA/100: An updated version of ATA/66 that increases data transfer rates to 100 MBps.
ATM- Asynchronous Transfer Mode -- International standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media such as E3, SONET, and T3.
ATX- The modern-day shape and layout of PC motherboards. It improves on the previous standard, the Baby AT form factor, by rotating the orientation of the board 90 degrees. This allows for a more efficient design, with disk drive cable connectors nearer to the drive bays and the CPU closer to the power supply and cooling fan.
AVI- Stands for Audio/Video Interleaved. AVI is the most common format for audio/video data on the PC.
Backbone- This term is often used to describe the main line or series of connections in a network. The backbones of the Internet are high-speed data highways serving as a major access points to which other networks connect.
Backup- To copy files to a second medium (a disk or tape) as a precaution in case the first medium fails. One of the cardinal rules in using computers is. Back up your files regularly. Even the most reliable computer is apt to break down eventually. Many professionals recommend that you make two, or even three, backups of all your files. To be especially safe, you should keep one backup in a different location from the others.
You can back up files using operating system commands, or you can buy a special-purpose backup utility. Backup programs often compress the data so that backups require fewer disks.
(1) The act of backing up. (2) A substitute or alternative. The term backup usually refers to a disk or a tape that contains a copy of data.
Bandwidth- How much stuff you can send through a connection. Usually measured in bits-per-second. A full page of English text is about 16,000 bits. A fast modem can move about 57,000 bits in one second. Full-motion full-screen video would require roughly 10,000,000 bits-per-second, depending on compression.
Baud- Pronounced bawd. The term is named after J.M.E. Baudot, the inventor of the Baudot telegraph code. In common usage the baud rate of a modem is how many bits it can send or receive per second. Technically, baud is the number of times per second that the carrier signal shifts value - for example a 1200 bit-per-second modem actually runs at 300 baud, but it moves 4 bits per baud (4 x 300= 1200 bits per second).
BBS- Stands for Bulletin Board Service. A computerized meeting and announcement system that allows people to carry on discussions, upload and download files, and make announcements without the people being connected to the computer at the same time.
Beta- Preliminary or testing stage of a software or hardware product; "a beta version"; "beta software"
BIOS- Stands for Audio/Video Interleaved. AVI is the most common format for audio/video data on the PC.Stands for Basic Input/Output System. The BIOS gives the computer a little built-in starter kit to run the rest of softwares from floppy disks (FDD) and hard disks (HDD). The BIOS is responsible for booting the computer by providing a basic set of instructions.
Binary- This is a basic system of numbering using ones and zeros.
Bit- (Binary DigIT) A single digit number in base-2, in other words, either a 1 or a zero. The smallest unit of computerized data. Bandwidth is usually measured in bits-per-second.
Binary- This is a basic system of numbering using ones and zeros.
Blog- (Slang term for a Weblog) This is a publicly accessible personal journal for an individual. Similar to a personal diary, but shared over the web. The activity of updating a blog is "blogging" and someone who keeps a blog is a "blogger." Blogs are typically updated daily using software that allows people with little or no technical background to update and maintain the blog. Postings on a blog are almost always arranged in chronological order with the most recent additions featured most prominently.
Bluetooth- Radio technology that connects electronic devices without using a cable. Data and voice can be exchanged at ranges of up to 10 meters without the need for devices to be lined up together.
BMP- (pronounced "bimp"): It's a bitmap, an image made up of little dots.
BNC- Different sources expand BNC as Bayonet Navy Connector, British Naval Connector, Bayonet Neill Concelman or Bayonet Nut Connection. A connector widely used in the CCTV industry, usually for coaxial cable. Easy to install and reliable with little video signal loss. Pictures of BNC Connectors
Boot Disk- A diskette from which you can boot your computer. Normally, your computer boots from a hard disk, but if the hard disk is damaged (for example, by a virus), you can boot the computer from a bootable diskette. For this reason, it's a good idea to make sure you always have a bootable diskette on hand. In Windows 95, you can create a bootable diskette by following these steps:
- Insert a blank, formatted diskette in the floppy drive
- Select Start->Settings->Control Panel
- Open Add/Remove Programs
- Select the Startup Disk tab and press the Create Disk... button
A bootable diskette is also called a bootable floppy, boot disk, and startup disk.
Buffer- A place, especially in RAM, for the temporary storage of data for the purpose of speeding up an operation such as printing or disk access. Data from a buffer is available more quickly than data from where the buffer got it. Typically buffers get data before it is needed so it will be ready quickly when it is needed. Similar to cache.
Browser- A browser is the software used for viewing pages on the web. Two examples are Microsoft Internet Explorer and Netscape Navigator.
BUS- A collection of wires through which data is Transmitted from one part of a computer to another. You can think of a bus as a highway on which data Travels within a computer. When used reference to Personal computers, the term bus usually refers to Internal bus.
This is a bus that connects all the internal computer components to the CPU and main memory. There's also an expansion bus that enables expansion boards to access the CPU and memory.
All buses consist of two parts -- an address bus and a data bus. The data bus transfers actual data whereas the address bus transfers information about where the data should go.
The size of a bus, known as its width, is important because it determines how much data can be transmitted at one time. For example, a 16-bit bus can transmit 16 bits of data, whereas a 32-bit bus can transmit 32 bits of data.
Every bus has a clock speed measured in MHz. A fast bus allows data to be transferred faster, which makes applications run faster. On PCs, the old ISA bus is being replaced by faster buses such as PCI.
Nearly all PCs made today include a local bus for data that requires especially fast transfer speeds, such as video data. The local bus is a high-speed pathway that connects directly to the processor.
In networking, a bus is a central cable that connects all devices on a local-area network (LAN). It is also called the backbone.
Bus Mastering- A technique that allows certain advanced bus architectures to delegate control data transfers between the CPU and associated peripheral devices to an add-in board. This gives greater system bus access and higher data transfer rates than conventional systems.
Bridge- A device which forwards traffic between
network segments based on data link layer information.
These segments would have a common network layer address.
Every network should only have one root bridge.
Byte- Unit of memory or data needed to represent one character in binary (1s and 0s) form. One byte is usually 8 bits.
Cable modem (CM)- Client device for providing data over a cable TV network.
Cache- A special block of fast memory used for temporary storage of data for quick retrieval. Compare buffer. (Think of a buffer as a temporary holding place between two devices, and a cache as a temporary holding place for one device.)
Cache RAM- Cache (usually SRAM) stores frequently requested data and instructions. It is a small block of high-speed memory located between the CPU and the main memory. When your computer processor needs data, it will check the Cache first to see if it is there. If the data is not there, it will retrieve it from the slower main memory.
CATV- Community Antenna Television or Cable TV system. Can be all coaxial or HFC (Hybrid Fiber Coax) based.
CD-ROM- (Compact Disc Read-Only Memory) An optical storage medium that can hold about 600 MB of data and is accessed with lasers.
CGA- Stands for Color Graphics Adapter. IBM's first microcomputer color standard. CGA allowed a maximum of four colors at a resolution of 320 x 200 or two colors at 640 x 200.
CGI- The Common Gateway Interface. A standard for running external programs from a World-Wide Web HTTP server. What is returned from the CGI program is based on what was requested, and this information can be accessed and returned to the user in many different ways.
Chassis- The physical framework of the computer system that houses modules, wiring, and power supplies.
CICS- Customer Information Control System. A general purpose IBM mainframe-based transaction management system. CICS is one of IBM's most widely used database / data communications subsystems.
Clock Speed- The clock speed is the frequency which determines how fast devices that are connected to the system bus operate. The speed is measured in millions of cycles per second (MHz or megahertz) and is generated by a quartz crystal on the motherboard which acts as a kind of metronome. Devices that are synchronized with the clock may run faster or slower but their speed is determined by multiplying or dividing a factor by the clock speed.
Clustering- A technique in which two or more servers are interconnected and can access a common storage pool. Clustering prevents the failure of a single file server from denying access to data and adds computing power to the network for large numbers of users.
CMOS- Abbreviation of complementary metal oxide semiconductor. Pronounced see-moss, CMOS is a widely used type of semiconductor. CMOS semiconductors use both NMOS (negative polarity) and PMOS (positive polarity) circuits. Since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. This makes them particularly attractive for use in battery-powered devices, such as portable computers. Personal computers also contain a small amount of battery-powered CMOS memory to hold the date, time, and system setup parameters.
CMTS- Cable Modem Termination System. Central device for connecting the cable TV network to a data network like the internet. Normally placed in the headend of the cable TV system.
COBOL- Stands for Common Business Oriented Language. A computer programming language invented during the second generation of computers and designed to meet the needs of business. Although less often used today, it was well-suited for writing programs that process large files and generate reports.
Codec
- Short for compressor/decompressor, a codec is any technology for compressing and decompressing data. Codecs can be implemented in software, hardware, or a combination of both. Some popular codecs for computer video include MPEG, Indeo and Cinepak.
- In telecommunications, (short for coder/decoder) a device that encodes or decodes a signal. For example, telephone companies use codecs to convert binary signals transmitted on their digital networks to analog signals converted on their analog networks.
- translation of a binary value into a voltage that can be transmitted over a wire.
Cold Boot- A cold reboot (also known as a hard reboot) is when power to a computer is cycled (turned on and off) or a special reset signal to the processor is triggered (from a front panel switch of some sort). This restarts the computer without first performing the usual shut-down procedure. (With many operating systems, especially those with disc caches, after a hard reboot the system may well be in an "unclean" state, and require that checks and repairs to on-disc file system structures be performed before normal operation can begin.) It may be caused by power failure, be done by accident, or be done deliberately as a last resort because nothing else to retrieve the system from a "hung" state works.
Collision- When two hosts transmit on a network at
once causing their packets to collide and corrupt each
other.
Collision Detection- A class of methods for sharing a data
transmission medium in which hosts transmit as soon as they
have data to send and then check to see whether their
transmission has suffered a collision with another host's.
If a collision is detected then the data must be resent. The
resending algorithm should try to minimise the chance that two
hosts's data will repeatedly collide. For example, the
CSMA/CD protocol used on Ethernet specifies that they
should then wait for a random time before re-transmitting.
COM- Stands for Component Object Module. In DOS systems, the name of a serial communications port. DOS supports four serial ports: COM1, COM2, COM3, and COM4. However, most software uses system interrupts to access the serial ports, and there are only two IRQ lines reserved. This means that the four COM ports share the same two IRQ lines. Typically, COM1 and COM3 use IRQ4, while COM2 and COM4 use IRQ3. So in general, if you have two devices, one of which is attached to COM1 and the other to COM3, you cannot use them simultaneously.
Command Line- Commands you type to run an application. You can type commands at an MS-DOS prompt or in the Run dialog box in the Program Manager of Windows. Interfaces in which you type commands rather than choose them from a menu are often called command line interfaces. MS-DOS has a command line interface while the Macintosh does not.
Compiler- This is an application that converts a programming language into a machine language program.
Config.SYS- The configuration file for DOS systems. Whenever a DOS computer boots up, it reads the CONFIG.SYS file (if it exists) and executes any commands in it. The most common commands are BUFFERS= and FILES=, which enable you to specify the buffer size and the number of files that can be open simultaneously. In addition, you can enter commands that install drivers for devices.
Contrast Ratio- TIs a method of measuring a dynamic range. The higher the contrast ratio, the more detailed the image will be. Blacks will be blacker, whites will be whiter, and particularly text on the image will be more vivid. A typical LCD monitor will have a contrast ratio of about 200:1.
Controller- A device that controls the transfer of data from a computer to a peripheral device and vice versa. For example, disk drives, display screens, keyboards, and printers all require controllers. In personal computers, the controllers are often single chips. When you purchase a computer, it comes with all the necessary controllers for standard components, such as the display screen, keyboard, and disk drives. If you attach additional devices, however, you may need to insert new controllers that come on expansion boards.
Controllers must be designed to communicate with the computer's expansion bus. There are three standard bus architectures for PCs -- the AT bus, PCI (Peripheral Component Interconnect), and SCSI. When you purchase a controller, therefore, you must ensure that it conforms to the bus architecture that your computer uses.
Conventional Memory- On DOS systems, conventional memory refers to the portion of memory that is available to standard DOS programs. DOS systems have an address space of 1MB (megabyte), but the top 384K (called high memory) is reserved for system use. This leaves 640K of conventional memory. Everything above 1MB is either extended or expanded memory.
CPE- Customer Premises Equipment. Used to describe the PC and/or other equipment, that the customer may want to connect to the cable modem
CPM: (Cost Per Thousand)- The practice of calculating a cost per 1000 ad displays. It is used by programs that pay on an impression basis -- with the CPM rate being the amount you earn for every 1000 times an advertisement is displayed. For example, a $5 CPM means you earn $5 every time 1000 ads are displayed on your site. CPM can also be calculated for pay-per-sale, pay-per-lead and pay-per-click programs by using this formula:
Amount earned / (number of impressions/1000)
CPU- Central Processing Unit. In a microcomputer, a processor on an IC chip (called a microprocessor) that serves as the heart of the computer. It interprets and carries out instructions, performs numeric computations, and controls the peripherals connected to it. Often the entire system unit is called the CPU.
CSS- Stands for Cascading Style Sheets.
Cyberspace- Author William Gibson in his novel Neuromancer describes a more highly developed form of the Internet and who originally coined the term Cyberspace. The word Cyberspace is currently used to describe the whole range of information resources available through computer networks.
Cyberpunk- Cyberpunk was originally a cultural sub-genre of science fiction taking place in a not-so-distant, dystopian, over-industrialized society. The term grew out of the work of William Gibson and Bruce Sterling and has evolved into a cultural label encompassing many different kinds of human, machine, and punk attitudes. It includes clothing and lifestyle choices as well.
Source: "The Free On-line Dictionary of Computing, http://www.foldoc.org/, Editor Denis Howe"
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Network Technologies