Computer Dictionary

File Sharing

2012-01-29T22:08:00.000+07:00

File sharing is the practice of the distribution of or access to digitally stored information, such as computer programs, multimedia (audio, pictures and video), electronic books or documents. It can be implemented by a variety of ways. Common methods for storage, transmission and distribution in file sharing are used include manual sharing by using removable media, centralized servers in computer networks, World Wide Web-based hyperlinks documents and the use of distributed peer-to-peer networks.

Cloud storage

2012-01-29T21:54:00.000+07:00

Cloud storage is a model of networked online storage where data is stored on virtualized pools of storage which are generally hosted by third parties.
Hosting companies operate large data centers, and people who require their data to be hosted buy or lease storage capacity from them and use it for their storage needs. The data center operators, in the background, virtualize the resources according to the requirements of the customer and expose them as storage pools, which the customers can themselves use to store files or data objects. Physically, the resource may span across multiple servers.

Cloud storage services may be accessed through a web service application programming interface (API), or through a Web-based user interface.

Hexadecimal

2009-12-25T23:09:00.005+07:00

Hexadecimal (also base 16, or hexadecimal) is a positional numeral system with a radix, or base, of 16. Sixteen of these using symbols different, most often the symbols 0-9 to represent values zero to nine, and A, B, C, D, E, F (or a through f) to represent the values ten to fifteen. For example, hexadecimal numbers are the same 2AF3, in decimal, for (2 × 163) + (10 × 162) + (15 × 16) + 3, or 10.995.

Each hexadecimal digit represents four binary digits (bits) (also called a "bite"), and the main use hexadecimal notation is a human-friendly representation of the values of binary code in computer and digital electronics. For example, byte values can range from 0-255 (decimal) but may be more easily represented as two hexadecimal digits in the range 00 to FF. Hexadecimal is also commonly used to represent the memory address of the computer.

WIFI

2009-12-13T20:16:00.008+07:00

WiFi is a trademark of the Wi-Fi Alliance that may be used with certified product that belong to a class of wireless local area network (WLAN) devices based on the IEEE 802.11 standard. Because of the close relationship with its underlying standard, the term Wi-Fi is often used as a synonym for IEEE 802.11 technology.

read more

TCP/IP

2009-12-13T20:14:00.003+07:00

TCP/IP. The Internet Protocol Suite is the set of communications protocols used for the Internet and other similar networks. It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard. Today's IP networking represents a synthesis of several developments that began to evolve in the 1960s and 1970s, namely the Internet and LANs (Local Area Network), which emerged in the mid- to late-1980s, together with the advent of the World Wide Web in the early 1990s.

read more

AMD

2009-12-13T20:06:00.006+07:00

Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Sunnyvale, California, that develops computer processors and related technologies for commercial and consumer markets. Its main products include microprocessors, motherboard chipsets, embedded processors and graphics processors for servers, workstations and personal computers, and processor technologies for handheld devices, digital television, automobiles, game consoles, and other embedded systems applications.

read more

UMTS

2009-12-13T19:38:00.007+07:00

UMTS : Universal Mobile Telecommunications System is one of the third-generation (3G) mobile telecommunications technologies, which is also being developed into a 4G technology. The first deployment of the UMTS is the release99 (R99) architecture. It is specified by 3GPP and is part of the global ITU IMT-2000 standard. The most common form of UMTS uses W-CDMA (IMT Direct Spread) as the underlying air interface but the system also covers TD-CDMA and TD-SCDMA (both IMT CDMA TDD). Being a complete network system, UMTS also covers the radio access network (UMTS Terrestrial Radio Access Network; UTRAN), the core network (Mobile Application Part; MAP) as well as authentication of users via USIM Cards (Subscriber Identity Module).
read more

HSDPA

2009-12-13T19:36:00.001+07:00

HSDPA
High-Speed Downlink Packet Access is an enhanced 3G (third generation) mobile phone communications protocol in the High-Speed Packet Access (HSPA) family, also created 3.5G, 3G + or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) which has data transfer speeds and higher capacity. Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14.0 Mbit / s. Further increasing the speed available with HSPA +, which provides speeds up to 42 Mbit / s downlink and 84 Mbit / s with Release 9 of the 3GPP standard.

EDGE

2009-12-13T19:30:00.005+07:00

EDGE
Enhanced Data rates for GSM Evolution, also known as Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC), or Enhanced Data rates for Global Evolution) is a backward-compatible digital mobile phone technology that allows improved data transmission rates, as an extension on top of standard GSM. EDGE is considered a 3G radio technology and is part of ITU's 3G definition. EDGE was deployed on GSM networks beginning in 2003— initially by Cingular (now AT&T) in the United States.
read more

GPRS

2009-12-13T19:22:00.003+07:00

General Packet Radio Service is a GSM data transmission technique that does not set up a continuous channel from a portable terminal for the transmission and reception of data, but transmits and receives data in packets. It makes very efficient use of available radio spectrum, and users pay only for the volume of data sent and received.

SAN

2009-12-13T10:11:00.002+07:00

A storage area network (SAN) is an architecture to attach remote computer storage devices (such as disk arrays, tape libraries, and optical jukeboxes) to servers in such a way that the devices appear as locally attached to the operating system. Although the cost and complexity of SANs are dropping, they are still uncommon outside larger enterprises.

Network-attached storage (NAS), in contrast to SAN, uses file-based protocols such as NFS or SMB/CIFS where it is clear that the storage is remote, and computers request a portion of an abstract file rather than a disk block.

DVD

2009-12-13T10:08:00.003+07:00

DVD, also known as Digital Versatile Disc or Digital Video Disc, is an optical disc storage media format, and was invented in 1995. Its main uses are video and data storage. DVDs are of the same dimensions as compact discs (CDs), but store more than six times as much data.
read more

WIMAX

2009-12-13T10:05:00.002+07:00

WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-multipoint links to portable and fully mobile internet access. The technology provides up to 10 Mbit/s broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL".

VBScript

2009-12-12T21:50:00.000+07:00

Visual BASIC Script

Microsoft's scripting language which is an extension of their Visual Basic language. VBScript can be used with Microsoft Office applications and others. It can also be embedded in web pages but can only be understood by Internet Explorer.

Visual Basic is a BASIC variant with object-oriented features. Objects include applications, windows and selections.

VMware

2009-12-12T21:47:00.002+07:00

A virtual machine is a software implementation of a machine (i.e. a computer) that executes programs like a physical machine.

VLAN

2009-12-12T21:43:00.001+07:00

A virtual LAN, commonly known as a VLAN, is a group of hosts with a common set of requirements that communicate as if they were attached to the same Broadcast domain, regardless of their physical location. A VLAN has the same attributes as a physical LAN, but it allows for end stations to be grouped together even if they are not located on the same network switch. Network reconfiguration can be done through software instead of physically relocating devices.

VGA

2009-12-12T21:40:00.001+07:00

Video Graphics Array

A display standard for IBM PCs, with 640 x 480 pixels in 16 colours and a 4:3 aspect ratio. There is also a text mode with 720 x 400 pixels.

IBM technical references define the *product name* of their original VGA display board as "Video Graphics Array", in contrast to the preceding boards, the "Color Graphics Adapter" (CGA) and "Enhanced Graphics Adapter" (EGA).

ROM

2009-12-12T21:38:00.000+07:00

Read-Only Memory

A type of data storage device which is manufactured with fixed contents. In its most general sense, the term might be used for any storage system whose contents cannot be altered, such as a gramophone record or a printed book; however, the term is most often applied to semiconductor integrated circuit memories, of which there are several types, and CD-ROM.

ROM is inherently non-volatile storage - it retains its contents even when the power is switched off, in contrast to RAM.

ROM is often used to hold programs for embedded systems since these usually have a fixed purpose. ROM is also used for storage of the lowest level bootstrap software (firmware) in a computer.

CPU

2009-12-12T21:36:00.001+07:00

Central Processing Unit

The part of a computer which controls all the other parts. Designs vary widely but, in general, the CPU consists of the control unit, the arithmetic and logic unit (ALU) and memory (registers, cache, RAM and ROM) as well as various temporary buffers and other logic.

The control unit fetches instructions from memory and decodes them to produce signals which control the other part of the computer. This may cause it to transfer data between memory and ALU or to activate peripherals to perform input or output.

A parallel computer has several CPUs which may share other resources such as memory and peripherals.

The term "processor" has to some extent replaced "CPU", though RAM and ROM are not normally considered as part of a processor. This is particularly true of common modern microprocessors though there have been microprocessors which include RAM and/or ROM on the same integrated circuit.

RS-232

2009-12-12T21:35:00.000+07:00

RS-232 is a standard for serial binary data signals connecting between a DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports. A similar ITU-T standard is V.24.

ZIP

2009-12-12T21:34:00.001+07:00

zip

1. Compression file format, To create a compressed archive (a "zip file") from one or more files using PKWare's PKZIP or a compatible archiver. Its use is spreading from MS-DOS now that portable implementations of the algorithm have been written.

zip is also the name of a Unix archiving utility compatible with PKZIP. unzip is the corresponding de-archiver.

2. Zip Drive (storage).

Router

2009-12-12T21:32:00.001+07:00

A device which forwards packets between networks. The forwarding decision is based on network layer information and routing tables, often constructed by routing protocols.

Yellow Pages

2009-12-12T21:31:00.001+07:00

Network Information Service

Sun Microsystems' Yellow Pages (yp) client-server protocol for distributing system configuration data such as user and host names between computers on a network.

Sun licenses the technology to virtually all other Unix vendors.

The name "Yellow Pages" is a registered trademark in the United Kingdom of British Telecommunications plc for their (paper) commercial telephone directory.

Rendering

2009-12-12T21:30:00.000+07:00

Rendering is the process of generating an image from a model, by means of computer programs. The model is a description of three-dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture, lighting, and shading information. The image is a digital image or raster graphics image. The term may be by analogy with an "artist's rendering" of a scene. 'Rendering' is also used to describe the process of calculating effects in a video editing file to produce final video output.

It is one of the major sub-topics of 3D computer graphics, and in practice always connected to the others. In the graphics pipeline, it is the last major step, giving the final appearance to the models and animation. With the increasing sophistication of computer graphics since the 1970s onward, it has become a more distinct subject.

Rendering has uses in architecture, video games, simulators, movie or TV special effects, and design visualization, each employing a different balance of features and techniques. As a product, a wide variety of renderers are available. Some are integrated into larger modeling and animation packages, some are stand-alone, some are free open-source projects. On the inside, a renderer is a carefully engineered program, based on a selective mixture of disciplines related to: light physics, visual perception, mathematics, and software development.

X Window System

2009-12-12T21:28:00.001+07:00

X Window System

A specification for device-independent windowing operations on bitmap display devices, developed initially by MIT's Project Athena and now a de facto standard supported by the X Consortium. X was named after an earlier window system called "W". It is a window system called "X", not a system called "X Windows".

X uses a client-server protocol, the X protocol. The server is the computer or X terminal with the screen, keyboard, mouse and server program and the clients are application programs. Clients may run on the same computer as the server or on a different computer, communicating over Ethernet via TCP/IP protocols. This is confusing because X clients often run on what people usually think of as their server (e.g. a file server) but in X, it is the screen and keyboard etc. which is being "served out" to the applications.

WAN

2009-12-12T21:26:00.001+07:00

Wide Area Network

A network, usually constructed with serial lines, extending over distances greater than one kilometre.

Readme

2009-12-12T21:25:00.001+07:00

An introduction traditionally included in the top-level directory of a Unix source distribution, containing a pointer to more detailed documentation, credits, miscellaneous revision history, notes, etc. The file may be named README, or READ.ME, or rarely ReadMe or readme.txt or some other variant.

In the Macintosh and IBM PC worlds, software is not usually distributed in source form, and the README is more likely to contain user-oriented material like last-minute documentation changes, error workarounds, and restrictions.

VB

2009-12-12T21:24:00.001+07:00

Visual BASIC

Popular event-driven visual programming system from Microsoft Corporation for Microsoft Windows. VB is good for developing Windows interfaces, it invokes fragments of BASIC code when the user performs certain operations on graphical objects on-screen. It is widely used for in-house application program development and for prototyping. It can also be used to create ActiveX and COM components.

QuickTime

2009-12-12T21:23:00.000+07:00

QuickTime is a proprietary multimedia framework developed by Apple Inc., capable of handling various formats of digital video, media clips, sound, text, animation, music, and interactive panoramic images. It is available for Mac OS classic (System 7 onwards), Mac OS X and Microsoft Windows operating systems. The latest version is QuickTime X (10.0) and is only available on Mac OS X v10.6.

Queue

2009-12-12T21:22:00.002+07:00

A first-in first-out data structure used to sequence multiple demands for a resource such as a printer, processor or communications channel. Objects are added to the tail of the queue and taken off the head.

A typical use of queues in an operating system involves a user command which places something on a queue, e.g. a file on a printer queue or a job on a job queue, and a background process or "demon" which takes things off and processes them (e.g. prints or executes them). Another common use is to pass data between an interrupt handler and a user process.

USB

2009-12-12T21:22:00.001+07:00

Universal Serial Bus

external peripheral interface standard for communication between a computer and external peripherals over an inexpensive cable using biserial transmission.

USB is intended to replace existing serial ports, parallel ports, keyboard, and monitor connectors and be used with keyboards, mice, monitors, printers, and possibly some low-speed scanners and removable hard drives. For faster devices existing IDE, SCSI, or emerging FC-AL or FireWire interfaces can be used.

USB works at 12 Mbps with specific consideration for low cost peripherals. It supports up to 127 devices and both isochronous and asynchronous data transfers. Cables can be up to five metres long and it includes built-in power distribution for low power devices. It supports daisy chaining through a tiered star multidrop topology. A USB cable has a rectangular "Type A" plug at the computer end and a square "Type B" plug at the peripheral end.

Before March 1996 Intel started to integrate the necessary logic into PC chip sets and encourage other manufacturers to do likewise. It was widely available by 1997. Later versions of Windows 95 included support for it. It was standard on Macintosh computers in 1999.

Query

2009-12-12T21:20:00.002+07:00

A user's request for information, generally as a formal request to a database or search engine.
SQL is the most common database query language.

URL

2009-12-12T21:20:00.001+07:00

Uniform Resource Locator
A standard way of specifying the location of an object, typically a web page, on the Internet. Other types of object are described below. URLs are the form of address used on the World-Wide Web. They are used in HTML documents to specify the target of a hyperlink which is often another HTML document (possibly stored on another computer).

UART

2009-12-12T21:18:00.001+07:00

Universal Asynchronous Receiver/Transmitter

An integrated circuit used for serial communications, containing a transmitter (parallel-to-serial converter) and a receiver (serial-to-parallel converter), each clocked separately.

The parallel side of a UART is usually connected to the bus of a computer. When the computer writes a byte to the UART's transmit data register (TDR), the UART will start to transmit it on the serial line. The UART's status register contains a flag bit which the computer can read to see if the UART is ready to transmit another byte. Another status register bit says whether the UART has received a byte from the serial line, in which case the computer should read it from the receive data register (RDR). If another byte is received before the previous one is read, the UART will signal an "overrun" error via another status bit.

The UART may be set up to interrupt the computer when data is received or when ready to transmit more data.

The UART's serial connections usually go via separate line driver and line receiver integrated circuits which provide the power and voltages required to drive the serial line and give some protection against noise on the line.

Data on the serial line is formatted by the UART according to the setting of the UART's control register. This may also determine the transmit and receive baud rates if the UART contains its own clock circuits or "baud rate generators". If incorrectly formated data is received the UART may signal a "framing error" or "parity error".

Often the clock will run at 16 times the baud rate (bits per second) to allow the receiver to do centre sampling - i.e. to read each bit in the middle of its allotted time period. This makes the UART more tolerant to variations in the clock rate ("jitter") of the incoming data.

An example of a late 1980s UART was the Intel 8450. In the 1990s, newer UARTs were developed with on-chip buffer space for data. This allowed higher transmission speed without data loss and without requiring such frequent attention from the computer. For example, the Intel 16550 has a 16 byte FIFO.

The term "Serial Communications Interface" (SCI) was first used at Motorola around 1975 to refer to their start-stop asyncronous serial interface device, which others were calling a UART.

Tag

2009-12-12T21:16:00.001+07:00

Tag
An SGML, HTML, or XML token representing the beginning (start tag: "

") or end (end tag: "

") of an element. In normal SGML syntax (and always in XML), a tag starts with a "<" and ends with an ">".

Network

2009-12-12T21:15:00.002+07:00

Hardware and software data communication systems.

The OSI seven layer model attempts to provide a way of partitioning any computer network into independent modules from the lowest (physical) layer to the highest (application) layer. Many different specifications exist at each of these layers.

Networks are often also classified according to their geographical extent: local area network (LAN), metropolitan area network (MAN), wide area network (WAN) and also according to the protocols used.

Scripting language

2009-12-12T21:15:00.001+07:00

scripting language

A loose term for any language that is weakly typed or untyped and has little or no provision for complex data structures. A program in a scripting language (a "script") is often interpreted (but see Ousterhout's dichotomy).

Scripts typically interact either with other programs (often as glue) or with a set of functions provided by the interpreter, as with the file system functions provided in a UNIX shell and with Tcl's GUI functions. Prototypical scripting languages are AppleScript, C Shell, MSDOS batch files, and Tcl.

Scroll

2009-12-12T21:12:00.002+07:00

scroll
To change the portion of a document displayed in a window or on a VDU screen. In a graphical user interface, scrolling is usually controlled by the user via scroll bars, whereas on a VDU the text scrolls up automatically as lines of data are output at the bottom of the screen.

NetBEUI

2009-12-12T21:11:00.003+07:00

NetBIOS Extended User Interface. The network transport protocol used by all of Microsoft's network systems and IBM's LAN Server based systems.

NetBEUI is often confused with NetBIOS. NetBIOS is the applications programming interface and NetBEUI is the transport protocol.

EEPROM

2009-12-12T21:11:00.002+07:00

EEPROM stands for Electrically Erasable Programmable Read-Only Memory and is a type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g., calibration tables or device configuration.

When larger amounts of static data are to be stored (such as in USB flash drives) a specific type of EEPROM such as flash memory is more economical than traditional EEPROM devices.

S Video

2009-12-12T21:11:00.001+07:00

S-Video

Is a video format offering a higher quality signal than composite video, but a lower quality than component video. This mid-level format divides the signal into two channels - luminance and chrominance.

RAM

2009-12-12T21:09:00.001+07:00

Random Access Memory

Is a data storage device for which the order of access to different locations does not affect the speed of access. This is in contrast to, say, a magnetic disk, magnetic tape or a mercury delay line where it is very much quicker to access data sequentially because accessing a non-sequential location requires physical movement of the storage medium rather than just electronic switching.

The most common form of RAM in use today is built from semiconductor integrated circuits, which can be either static (SRAM) or dynamic (DRAM). In the 1970s magnetic core memory was used. RAM is still referred to as core by some old-timers.

The term "RAM" has gained the additional meaning of read-write. Most kinds of semiconductor read-only memory (ROM) are actually "random access" in the above sense but are never referred to as RAM. Furthermore, memory referred to as RAM can usually be read and written equally quickly (approximately), in contrast to the various kinds of programmable read-only memory. Finally, RAM is usually volatile though non-volatile random-access memory is also used.

Interestingly, some DRAM devices are not truly random access because various kinds of "page mode" or "column mode" mean that sequential access is faster than random access.

JAR

2009-12-12T21:07:00.000+07:00

Java archive
A compressed archive file containing Java class files, filename extension: ".jar". The Java Development Kit contains a tool called "jar" for creating .jar files, similar to the standard Unix tar command. As well as archiving and compressing the Java class files, it also inserts a "manifest" file which can contain information about the class files, such as a digital signature. Combining class files into a single archive file makes it possible to download them in a single HTTP transaction. This, and the compression, speeds up execution of Java programs delivered via the Internet.

Jargon File

2009-12-12T21:06:00.003+07:00

The Jargon File is a glossary of hacker slang. The original Jargon File was a collection of hacker slang from technical cultures such as the MIT AI Lab, the Stanford AI Lab (SAIL), and others of the old ARPANET AI/LISP/PDP-10 communities, including Bolt, Beranek and Newman, Carnegie Mellon University, and Worcester Polytechnic Institute.

RAID

2009-12-12T21:06:00.001+07:00

Redundant Arrays of Independent Disks

(RAID. Originally "Redundant Arrays of Inexpensive Disks") A project at the computer science department of the University of California at Berkeley, under the direction of Professor Katz, in conjunction with Professor John Ousterhout and Professor David Patterson.

The project is reaching its culmination with the implementation of a prototype disk array file server with a capacity of 40 GBytes and a sustained bandwidth of 80 MBytes/second. The server is being interfaced to a 1 Gb/s local area network. A new initiative, which is part of the Sequoia 2000 Project, seeks to construct a geographically distributed storage system spanning disk arrays and automated libraries of optical disks and tapes. The project will extend the interleaved storage techniques so successfully applied to disks to tertiary storage devices. A key element of the research will be to develop techniques for managing latency in the I/O and network paths.

Qwerty

2009-12-12T21:04:00.001+07:00

QWERTY

Hardware (From the top left row of letter keys of most keyboards) Pertaining to a standard English-language typewriter keyboard (sometimes called the Sholes keyboard after its inventor), as opposed to Dvorak or foreign-language layouts (e.g. "keyboard AZERTY" in french-speaking countries) or a space-cadet keyboard or APL keyboard.

The QWERTY layout is a fine example of a fossil. It is sometimes said that it was designed to slow down the typist, but this is wrong; it was designed to allow *faster* typing - under a constraint now long obsolete. In early typewriters, fast typing using nearby type-bars jammed the mechanism. So Sholes fiddled the layout to separate the letters of many common digraphs (he did a far from perfect job, though; "th", "tr", "ed", and "er", for example, each use two nearby keys). Also, putting the letters of "typewriter" on one line allowed it to be typed with particular speed and accuracy for demos. The jamming problem was essentially solved soon afterward by a suitable use of springs, but the keyboard layout lives on.

Serial Port

2009-12-12T21:02:00.001+07:00

Serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals and various peripherals.

While such interfaces as Ethernet, FireWire, and USB all send data as a serial stream, the term "serial port" usually identifies hardware more or less compliant to the RS-232 standard, intended to interface with a modem or with a similar communication device.

In modern personal computers the serial port has largely been replaced by USB and Firewire for connections to peripheral devices. Many modern personal computers do not have a serial port since this legacy port has been superseded for most uses. Serial ports are commonly still used in applications such as industrial automation systems, scientific analysis, shop till systems and some industrial and consumer products. Server computers may use a serial port as a control console for diagnostics. Network equipment (such as routers and switches) often use serial console for configuration. Serial ports are still used in these areas as they are simple, cheap and their console functions are highly standardized and widespread. A serial port requires very little supporting software from the host system.

Packet

2009-12-12T21:01:00.001+07:00

packet

The unit of data sent across a network. "Packet" is a generic term used to describe a unit of data at any layer of the OSI protocol stack, but it is most correctly used to describe application layer data units ("application protocol data unit", APDU).

Mainboard

2009-12-12T21:00:00.002+07:00

A motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the main board, system board, or, on Apple computers, the logic board. It is also sometimes casually shortened to mobo.

Cat 6

2009-12-12T20:57:00.000+07:00

Category 6 Cable
American Standards Institute standard for UTP (Unshielded twisted pair) cables.
Category 6 cable, commonly referred to as Cat-6, is a cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. Compared with Cat-5 and Cat-5e, Cat-6 features more stringent specifications for crosstalk and system noise. The cable standard provides performance of up to 250 MHz and is suitable for 10BASE-T, 100BASE-TX (Fast Ethernet), 1000BASE-T / 1000BASE-TX (Gigabit Ethernet) and 10GBASE-T (10-Gigabit Ethernet). Category 6 cable has a reduced maximum length when used for 10GBASE-T; Category 6a cable, or Augmented Category 6, is characterized to 500MHz and has improved alien crosstalk characteristics, allowing 10GBASE-T to be run for the same distance as previous protocols. Category 6 cable can be identified by the printing on the side of the cable sheath.

Cat 5

2009-12-12T20:51:00.000+07:00

Category 5 Cable
American Standards Institute standard for UTP (Unshielded twisted pair) cables.

Category 5 cable is a twisted pair high signal integrity cable type often referred to as Cat5. Most cables are unshielded, relying on the twisted pair design for noise rejection, and some are shielded. Category 5 has been superseded by the Category 5e specification structured cabling for computer networks such as Ethernet, and is also used to carry many other signals such as basic voice services, token ring, and ATM (at up to 155 Mbit/s, over short distances).

CACHE

2009-12-12T20:45:00.000+07:00

cache is a collection of data duplicating original values stored elsewhere or computed earlier, where the original data is expensive to fetch (owing to longer access time) or to compute, compared to the cost of reading the cache. In other words, a cache operates as a temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data.

Caches have proven extremely effective in many areas of computing because access patterns in typical computer applications have locality of reference.

C Language

2009-12-12T20:44:00.001+07:00

C is a general-purpose computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system.

Although C was designed for implementing system software, it is also widely used for developing portable application software.[citation needed]

C is one of the most popular programming languages. It is widely used on many different software platforms, and there are few computer architectures for which a C compiler does not exist. C has greatly influenced many other popular programming languages, most notably C++, which originally began as an extension to C.

Operating System

2009-12-12T20:42:00.001+07:00

Operating system (OS) The low-level software which handles the interface to peripheral hardware, schedules tasks, allocates storage, and presents a default interface to the user when no application program is running.

The OS may be split into a kernel which is always present and various system programs which use facilities provided by the kernel to perform higher-level house-keeping tasks, often acting as servers in a client-server relationship.

Some would include a graphical user interface and window system as part of the OS, others would not. The operating system loader, BIOS, or other firmware required at boot time or when installing the operating system would generally not be considered part of the operating system, though this distinction is unclear in the case of a rommable operating system such as RISC OS.

The facilities an operating system provides and its general design philosophy exert an extremely strong influence on programming style and on the technical cultures that grow up around the machines on which it runs.

Online

2009-12-12T20:40:00.001+07:00

On line

1. Ready for use. E.g. "The graph plotter's fixed and on-line again".

2. Interactive as opposed to batch. Accessible via a computer (or terminal), rather than on paper or other medium.

3. Of a user, actively using a computer system, especially the Internet. E.g "I haven't been on-line for three days."

"On-line" should be hyphenated because it is compounded from two words but the hyphen is often omitted in names of organisations or services.

Octal

2009-12-12T20:38:00.001+07:00

Base 8. A number representation using the digits 0-7 only, with the right-most digit counting ones, the next counting multiples of 8, then 8^2 = 64, etc. For example, octal 177 is digital 127

Batch file

2009-12-12T20:34:00.001+07:00

A text file containing operating system commands which are executed automatically by the command-line interpreter. In Unix, this is called a "shell script" since it is the Unix shell which includes the command-line interpreter. Batch files can be used as a simple way to combine existing commands into new commands.

autoexec.bat is the best known example of an MS-DOS batch file.

BASIC

2009-12-12T20:32:00.000+07:00

Beginner's All-purpose Symbolic Instruction Code. A simple language oroginally designed for ease of programming by students and beginners.

BASIC exists in many dialects, and is popular on microcomputers with sound and graphics support. Most micro versions are interactive and interpreted.

BASIC has become the leading cause of brain-damage in proto-hackers. This is another case (like Pascal) of the cascading lossage that happens when a language deliberately designed as an educational toy gets taken too seriously. A novice can write short BASIC programs (on the order of 10-20 lines) very easily; writing anything longer is (a) very painful, and (b) encourages bad habits that will make it harder to use more powerful languages well. This wouldn't be so bad if historical accidents hadn't made BASIC so common on low-end micros. As it is, it ruins thousands of potential wizards a year.

Originally, all references to code, both GOTO and GOSUB (subroutine call) referred to the destination by its line number. This allowed for very simple editing in the days before text editors were considered essential. Just typing the line number deleted the line and to edit a line you just typed the new line with the same number. Programs were typically numbered in steps of ten to allow for insertions. Later versions, such as BASIC V, allow GOTO-less structured programming with named procedures and functions, IF-THEN-ELSE-ENDIF constructs and WHILE loops etc.

Early BASICs had no graphic operations except with graphic characters. In the 1970s BASIC interpreters became standard features in mainframes and minicomputers. Some versions included matrix operations as language primitives.

BACKUP

2009-12-12T20:31:00.000+07:00

backup or the process of backing up refer to making copies of data so that these additional copies may be used to restore the original after a data loss event. These additional copies are typically called "backups." The verb is back up in two words, whereas the noun is backup (often used like an adjective in compound nouns).

Backups are useful primarily for two purposes. The first is to restore a state following a disaster (called disaster recovery). The second is to restore small numbers of files after they have been accidentally deleted or corrupted. Data loss is also very common. 66% of internet users have suffered from serious data loss.

Since a backup system contains at least one copy of all data worth saving, the data storage requirements are considerable. Organizing this storage space and managing the backup process is a complicated undertaking. A data repository model can be used to provide structure to the storage. In the modern era of computing there are many different types of data storage devices that are useful for making backups. There are also many different ways in which these devices can be arranged to provide geographic redundancy, data security, and portability.

Before data is sent to its storage location, it is selected, extracted, and manipulated. Many different techniques have been developed to optimize the backup procedure. These include optimizations for dealing with open files and live data sources as well as compression, encryption, and de-duplication, among others. Many organizations and individuals try to have confidence that the process is working as expected and work to define measurements and validation techniques. It is also important to recognize the limitations and human factors involved in any backup scheme.

Backbone

2009-12-12T20:28:00.001+07:00

backbone
The top level in a hierarchical network. Stub networks and transit networks which connect to the same backbone are guaranteed to be interconnected.

XGA

2009-12-12T20:23:00.000+07:00

XGA, the Extended Graphics Array, is an IBM display standard introduced in 1990. Today, it is the most common appellation of the 1024×768 pixels display resolution, but the official definition is broader than that. It was not a new and improved replacement for Super VGA, but rather became one particular subset of the broad range of capabilities covered under the "Super VGA" umbrella.

The initial version of XGA expanded upon IBM's VGA, adding support for two resolutions:

* 800×600 pixels with high color (16 bits per pixel; i.e.. 65,536 colors).
* 1024×768 pixels with a palette of 256 colors (8 bits per pixel)

Like its predecessor (the IBM 8514), XGA offered fixed function hardware acceleration to offload processing of 2D drawing tasks. XGA and 8514 could offload line-draw, bitmap-copy (bitblt), and color-fill operations from the host CPU. XGA's acceleration was faster than 8514's, and more comprehensive in that it supported more drawing primitives and XGA's 16 bits per pixel (65,536 color) display-mode.

XGA-2 added true color mode for 640×480, 1024×768 support for high color and higher refresh rates, and improved accelerator performance. All XGA modes have a 4:3 aspect ratio rounded to 8 pixels.

XGA should not be confused with VESA's EVGA (Extended Video Graphics Array) which was released at a similar time.

XEON

2009-12-12T20:20:00.000+07:00

The Xeon is a brand of multiprocessing- or multi-socket-capable x86 microprocessors from Intel Corporation targeted at the non-consumer server, workstation and embedded system markets.

XHTML

2009-12-12T20:19:00.001+07:00

Extensible Hypertext Markup Language, or XHTML, is a family of XML markup languages that mirror or extend versions of the widely used Hypertext Markup Language (HTML), the language in which web pages are written.

While HTML (prior to HTML5) was defined as an application of Standard Generalized Markup Language (SGML), a very flexible markup language framework, XHTML is an application of XML, a more restrictive subset of SGML. Because XHTML documents need to be well-formed, they can be parsed using standard XML parsers—unlike HTML, which requires a lenient HTML-specific parser.

XHTML 1.0 became a World Wide Web Consortium (W3C) Recommendation on January 26, 2000. XHTML 1.1 became a W3C Recommendation on May 31, 2001. XHTML5 is undergoing development as of September 2009, as part of the HTML5 specification.

INTEL

2009-12-12T20:08:00.001+07:00

Intel is the world's largest semiconductor chip maker, based on revenue. The company is the inventor of the x86 series of microprocessors, the processors found in most personal computers. Intel was founded on July 18, 1968, as Integrated Electronics Corporation (though a common misconception is that "Intel" is from the word intelligence) and is based in Santa Clara, California, USA. Intel also makes motherboard chipsets, network interface controllers and integrated circuits, flash memory, graphic chips, embedded processors, and other devices related to communications and computing. Founded by semiconductor pioneers Robert Noyce and Gordon Moore, and widely associated with the executive leadership and vision of Andrew Grove, Intel combines advanced chip design capability with a leading-edge manufacturing capability. Originally known primarily to engineers and technologists, Intel's successful "Intel Inside" advertising campaign of the 1990s made it and its Pentium processor household names.

Intel was an early developer of SRAM and DRAM memory chips, and this represented the majority of its business until the early 1980s. While Intel created the first commercial microprocessor chip in 1971, it was not until the success of the personal computer (PC) that this became their primary business. During the 1990s, Intel invested heavily in new microprocessor designs fostering the rapid growth of the PC industry. During this period Intel became the dominant supplier of microprocessors for PCs, and was known for aggressive and sometimes controversial tactics in defense of its market position, particularly against AMD, as well as a struggle with Microsoft for control over the direction of the PC industry.[4][5] The 2009 rankings of the world's 100 most powerful brands published by Millward Brown Optimor showed the company's brand value rising 4 places – from number 27 to number 23.

ActiveX

2009-12-12T20:02:00.000+07:00

ActiveX is a framework for defining reusable software components (known as controls) that perform a particular function or a set of functions in Microsoft Windows in a way that is independent of the programming language used to implement them. A software application can then be composed from one or more of these components in order to provide its functionality.[1]

It was introduced in 1996 by Microsoft as a development of its Component Object Model (COM) and Object Linking and Embedding (OLE) technologies and it is commonly used in its Windows operating system, although the technology itself is not tied to it.

Many Microsoft Windows applications — including many of those from Microsoft itself, such as Internet Explorer, Microsoft Office, Microsoft Visual Studio, and Windows Media Player — use ActiveX controls to build their feature-set and also encapsulate their own functionality as ActiveX controls which can then be embedded into other applications. Internet Explorer also allows embedding ActiveX controls onto web pages.

Nano

2009-12-12T19:58:00.001+07:00

nano

Nano is a prefix meaning "extremely small." When quantifiable, it translates to one-billionth, as in the nanosecond . Nano comes from the Greek word "nanos," meaning "dwarf."

Z80

2009-12-12T19:57:00.000+07:00

The Zilog Z80 is an 8-bit microprocessor designed and sold by Zilog from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes. The Z80 and its derivatives and clones make up one of the most commonly used CPU families of all time, and, along with the MOS Technology 6502 family, dominated the 8-bit microcomputer market from the late 1970s to the mid-1980s.

Although Zilog made early attempts with advanced mini-computer like versions of the Z80-architecture (Z800 and Z280), these chips never caught on. The company was also trying hard in the workstation market with its Z8000 and 32-bit Z80000 (both unrelated to Z80). In recent decades Zilog has refocused on the ever-growing market for embedded systems (for which the original Z80 and the Z180 were designed) and the most recent Z80-compatible microcontroller family, the fully pipelined 24-bit eZ80 with a linear 16 MB address range, has been successfully introduced alongside the simpler Z180 and Z80 products.

Zilog licensed the Z80 core to any company wishing to make the device royalty free, though many East European and Russian manufacturers made unlicensed copies. This enabled a small company's product to gain acceptance in the world market since second sources from far larger companies such as Toshiba started to manufacture the device. Consequently Zilog has made less than 50% of the Z80s since its conception.

Zoom

2009-12-12T19:56:00.000+07:00

To show a smaller area of an image at a higher magnification ("zoom in") or a larger area at a lower magnification ("zoom out"), as though using a zoom lense on a camera.

Unlike in an optical system, zooming in on a computer image does not necessarily increase the amount of detail displayed since this is limited by what is actually stored in the image. Similarly, you cannot zoom out beyond the full size of the image.

NAT

2009-12-12T19:54:00.001+07:00

NAT
Short for Network Address Translation, NAT as specified in RFC 1631 is an Internet standard that enables a local-area network (LAN) to use one or more IP addresses for internal traffic and a second for external. A network NAT is commonly used by home users to allow multiple computers to easily connect to a broadband connection. NAT is also used to hide Internet network addresses by using the single NAT address.

Today, there are two different variants of NAT used. NAPT, which is short for Network Address Port Translation; and PAT, which is short for Port Address Translation.

Macro

2009-12-12T19:51:00.001+07:00

Macro
Series of keyboard, mouse actions, and/or other computer steps recorded to be run quickly and easily. Macros are commonly created for operations that are commonly performed on a computer. Using a macro allows a user to quickly perform an operation with a press of a key or the execution of a command.

Mouse

2009-12-12T19:50:00.004+07:00

a mouse (plural mouses, mice, or mouse devices.) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface.

The name mouse, originated at the Stanford Research Institute, derives from the resemblance of early models (which had a cord attached to the rear part of the device, suggesting the idea of a tail) to the common mouse.

The first marketed integrated mouse – shipped as a part of a computer and intended for personal computer navigation – came with the Xerox 8010 Star Information System in 1981. However, the mouse remained relatively obscure until the appearance of the Apple Macintosh; in 1984 PC columnist John C. Dvorak ironically commented on the release of this new computer with a mouse: “There is no evidence that people want to use these things".

A mouse now comes with most computers and many other varieties can be bought separately.

Macro virus

2009-12-12T19:50:00.002+07:00

Macro virus
A MAC or Macro virus is a type of computer virus that spreads to other computers through software programs that utilize macros. For example, Microsoft Word and Microsoft Excel are two popular and widely used programs that are capable of executing macros. Macro viruses written for these programs can quickly spread by infecting other related documents each time the document is open. Because these types of files are commonly used and sent through e-mail, a computer network can be quickly infected by these viruses

MAC

2009-12-12T19:49:00.002+07:00

   1. Short for Medium Access Control, a MAC address also known as a physical address is a unique address number formatted in hexadecimal format and given to each computer and/or network device on a computer network. Below is an example of a MAC address:

      A1:B2:C3:D4:E5:F6

      Because a MAC address is a unique address, a computer network will not have the same MAC address assigned to more than one computer or network device.

      Users who are running Microsoft Windows who are interested in learning their MAC address or another computer's MAC address can use the nbstat or ipconfig command. Additional information about these command can be found on our nbtstat command page and ipconfig command page.

      If you're running Linux / Unix or a variant, you can determine the MAC Address or hardware address using the ifconfig command. Additional information about this command can be found on our ifconfig command page.

   2. Short for Apple Macintosh, .

Mac

2009-12-12T19:48:00.000+07:00

Macintosh
Sometimes abbreviated as Mac, Macintosh is a type of computer designed by Apple Computer Inc. that was introduced in 1984. Macintosh computers are known for their easy to use graphical user interface that uses icons, windows and a mouse for point and click operation; opposed to the IBM computers, that at the time used MS-DOS, a non graphical user interface.

Laser

2009-12-12T19:45:00.002+07:00

Laser
Short for Light Amplification by Stimulated Emission of Radiation, a laser is an intense beam of light. Lasers are commonly used in data storage and retrieval in computers. For example, CD-ROM drives utilize a laser to read and write information.

Laptop

2009-12-12T19:44:00.001+07:00

Laptop computer
Dell Latitude D610 laptopAlso known as a notebook, a laptop is a portable computer that is about the size as a large binder and has the same abilities as a standard home desktop computer but is small enough for easy mobility. Portable computers run off AC power and also have the ability to run off a NiMH, NiCad, or other type of battery pack for a few hours.

LAN

2009-12-12T19:43:00.001+07:00

LAN
Short for Local-Area Network, a LAN is a network that has networking equipment and/or computers in close proximity to each other, capable of communicating, sharing resources and sharing information. Most home networks and businesses who have their own network are on a LAN.

Level 1 caching

2009-12-12T19:41:00.002+07:00

Level 1 caching
Also known as L1 cache, primary cache, or internal cache. When referring to computer processors, L1 cache is cache built on to the processor and is commonly the fastest cache in the computer.

Keyword

2009-12-12T19:40:00.000+07:00

Keyword

1. When referring to a search function, a keyword is a word or group of words that help the search locate a better match for their search.
2. Keyword is also a term used with AOL when searching for a specific site.

Dialup

2009-12-12T19:38:00.005+07:00

Dial-up
Using telephone line to dial for internet access. The user's computer or router uses an attached modem connected to a telephone line to dial into an Internet service provider's (ISP) node to establish a modem-to-modem link, which is then used to route Internet Protocol packets between the user's equipment and hosts.

The term was coined during the early days of computer telecommunications when modems were needed to connect dumb terminals or computers running terminal emulator software to mainframes, minicomputers, online services and bulletin board systems via a telephone line.

Keylogger

2009-12-12T19:38:00.003+07:00

Key logger
Also known as a keystroke logger, a keylogger is a software program or hardware device that is used to monitor and log each of the keys a user types into a computer keyboard. The user who installed the program or hardware device can then view all keys typed in by that user. Because these programs and hardware devices monitor the keys typed in, a user can easily find user passwords and other information a user may not wish others to know about.

Additionally, users who are using a hardware device and have access to a computer can easily connect these devices to the back of a computer, often without a user knowing about them, and then disconnect the device and connect it to another computer to obtain all the information.

Users who are concerned about their privacy or have sensitive data may wish to consider anti-keylogger protection software that is designed to prevent and stop hardware and software keyloggers.

Keygen

2009-12-12T19:37:00.002+07:00

Keygen
A generator that creates a key or CD-KEY for a software program. Keygens are often used in software piracy because the user illegally copied the software and needs a key to install the program on his or her computer.

Keyboard

2009-12-12T19:35:00.002+07:00

Keyboard
One of the main input devices used on a computer, a PC's keyboard looks very similar to the keyboards of electric typewriters, with some additional keys

JVM

2009-12-12T19:34:00.001+07:00

JVM
Short for Java Virtual Machine, JVM is software that interprets Java bytecode and converts it into machine language to execute it on the computer.

JavaScript

2009-12-12T19:33:00.002+07:00

JavaScript
Formerly known as LiveScript and renamed to JavaScript in 1995, JavaScript is an interpreted programming language that allows a web designer the ability to easily insert code into their web page. JavaScript is commonly placed into a HTML, ASP, or a similar type of file and run directly from the web page to perform tasks such as printing the time and date, creating a calendar, or other tasks that are not possible through plain HTML.

Java

2009-12-12T19:32:00.001+07:00

Java
Originally known as oak, Java is a programming language developed by Sun Microsystems that was first introduced to the public in 1995 and today is widely used to create Internet applications and other software programs.

When used on the Internet, Java allows for small programs known as an applets to be downloaded, enabling the user to perform a specific function or feature that is not available with the standard web browser. Unlike JavaScript, the users must download and/or install the applet or program before being able to utilize the program.

Image

2009-12-12T19:29:00.002+07:00

Image
A computer generated graphic or modified picture that appears on-screen. Below is an example of a computer generated image. This type of image is generated by only using a computer software program.

I-beam pointer

2009-12-12T19:27:00.002+07:00

I-beam pointer
Also know as the I-cursor, the I-beam pointer is a mouse cursor shaped similar to the capital letter "I" that indicates that text can be highlighted, inserted or changed. The image to the right is an example of what an I cursor may look like.

IBM compatible

2009-12-12T19:26:00.002+07:00

Also referred to as an IBM clone, IBM compatible is a term used to describe a computer, hardware or software that is IBM/PC Compatible. This does not necessarily mean that the computer was manufactured by IBM.

Hardware

2009-12-12T19:23:00.002+07:00

Hardware is best described as a device that is physically connected to your computer or something that can be physically touched. A CD-ROM, Monitor, Printer, and video card are all examples of computer hardware. Without any hardware your computer would not exist and software would have nothing to run on.

harddisk

2009-12-12T19:21:00.000+07:00

Hard disk
Rigid circular disk located inside a computer hard disk drive. The term hard disk is often used as an abbreviation to hard disk drive.

Handshake

2009-12-12T19:20:00.001+07:00

Hand shake
Term used to describe the process of one computer establishing a connection with another computer or device. The handshake is often the steps of verifying the connection, the speed, and/or the authorization of the computer trying to connect to it. An example of handshaking is when a modem connects to another modem; the tones heard after the dialing is the handshake and can be thought of as the computers greeting each other.

Hard Boot

2009-12-12T19:19:00.000+07:00

Also known as cold boot is a term used to describe the process of turning on the computer after it has been powered off. For example, when you first turn your computer on after being off for the night that is referred to as cold booting the computer.

Hang

2009-12-12T19:17:00.002+07:00

Hang
Also referred to as hung, hang is a term used to describe when a computer stops operating when trying to run a program, boot up, or close out of a program. Usually this can occur when the computer has software or hardware conflictions.

Half duplex

2009-12-12T19:16:00.000+07:00

Half duplex
Signals that flow in both directions, but only one way at a time. In microcomputer communications, half duplex may refer to activation of the online local echo, which causes the modem to send a copy of transmitted data to the screen of the sending computer.

Hacker

2009-12-12T19:14:00.003+07:00

Hacker
1. A term that first started being used in the 1960s and was used to describe a programmer or someone who hacked out computer code, later the term evolved to an individual who had an advanced understanding of computers, networking, programming, and/or hardware but did not have any malicious intents.

Today, a hacker is often associated with an individual who illegally breaks into other computer systems to damage and/or steal information. Some users today who consider themselves leet may refer to themselves as haxors or h4x0rs. However, often these types of users are nothing more than script kiddies.

Although the media and most people think of hackers as malicious or evil, the majority of hackers are people who are curious about how computer, networks, and/or programs work and are often simply exploring and learning.

2. In computer online gaming a hacker is a term often associated with a gamer who is cheating.

GeForce

2009-12-12T19:12:00.001+07:00

GeForce
A product line of video cards released by NVIDIA.

Gateway

2009-12-12T19:10:00.002+07:00

Gateway

1. When referring to a network, a gateway is an address used as an entry point into another network. For example: 166.70.10.1 could be used as a gateway. It is common for .1 and .2 to be setup as a network's gateway. The gateway is commonly the address of a network device such as a network router.
2. Gateway is also a U.S. computer company. See our Gateway company information page for additional information about this company.

Gigo

2009-12-12T19:08:00.002+07:00

Gigo
Short for Garbage in, garbage out, Gigo is a software program's inability to interpret that bad data is received and because of this, the program may return incorrect results or may crash.

Game

2009-12-12T19:07:00.000+07:00

Game
A type of computer software that has been designed to entertain and/or educate an individual. Today, computer gaming is a big business and there are millions of different types of computer games that are enjoyed by people of all ages.