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A video card, video adapter, graphics accelerator card, display adapter, or graphics card is an expansion card which generates output images to a display. Most video cards offer added functions, such as accelerated rendering of 3D scenes and 2D graphics, video capture, TV-tuner adapter, MPEG-2/MPEG-4 decoding, FireWire, light pen, TV output, or the ability to connect multiple monitors (multi-monitor). Other modern high performance video cards are used for more graphically demanding purposes, such as PC games.

Video hardware is often integrated into the motherboard, however all modern motherboards provide expansion ports to which a video card can be attached. In this configuration it is sometimes referred to as a video controller or graphics controller. Modern low-end to mid-range motherboards often include a graphics chipset developed by the developer of the northbridge (i.e. an nForcechipset with Nvidia graphics or an Intel chipset with Intel graphics) on the motherboard. This graphics chip usually has a small quantity of embedded memory and takes some of the system’s main RAM, reducing the total RAM available. This is usually called integrated graphics or on-board graphics, and is low-performance and undesirable for those wishing to run 3D applications. A dedicated graphics card on the other hand has its own RAM and Processor specifically for processing video images, and thus offloads this work from the CPU and system RAM. Almost all of these motherboards allow the disabling of the integrated graphics chip in BIOS, and have an AGP, PCI, or PCI Express slot for adding a higher-performance graphics card in place of the integrated graphics.

The memory capacity of most modern video cards ranges from 128 MB to 8 GB. Since video memory needs to be accessed by the GPU and the display circuitry, it often uses special high-speed or multi-port memory, such as VRAM, WRAM, SGRAM, etc. Around 2003, the video memory was typically based on DDR technology. During and after that year, manufacturers moved towards DDR2, GDDR3, GDDR4 and GDDR5. The effective memory clock rate in modern cards is generally between 400 MHz and 3.8 GHz.

Video memory may be used for storing other data as well as the screen image, such as the Z-buffer, which manages the depth coordinates in 3D graphics, textures, vertex buffers, and compiled shader programs

The RAMDAC, or Random Access Memory Digital-to-Analog Converter, converts digital signals to analog signals for use by a computer display that uses analog inputs such as CRTdisplays. The RAMDAC is a kind of RAM chip that regulates the functioning of the graphics card. Depending on the number of bits used and the RAMDAC-data-transfer rate, the converter will be able to support different computer-display refresh rates. With CRT displays, it is best to work over 75 Hz and never under 60 Hz, in order to minimize flicker. (With LCD displays, flicker is not a problem.) Due to the growing popularity of digital computer displays and the integration of the RAMDAC onto the GPU die, it has mostly disappeared as a discrete component. All current LCDs, plasma displays and TVs work in the digital domain and do not require a RAMDAC. There are few remaining legacy LCD and plasma displays that feature analog inputs (VGA, component, SCART etc.) only. These require a RAMDAC, but they reconvert the analog signal back to digital before they can display it, with the unavoidable loss of quality stemming from this digital-to-analog-to-digital conversion.

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier (URI) and may be a web page, image, video, or other piece of content. Hyperlinks present in resources enable users easily to navigate their browsers to related resources. A web browser can also be defined as an application software or program designed to enable users to access, retrieve and view documents and other resources on the Internet. Although browsers are primarily intended to access the World Wide Web, they can also be used to access information provided by web servers in private networks or files in file systems. The major web browsers are Internet Explorer, Firefox, Google Chrome, Safari, and Opera.

The history of the web browser dates back to the late 1980s, when a variety of technologies laid the foundation for the first web browser, WorldWideWeb, by Tim Berners-Lee in 1991. That browser brought together a variety of existing and new software and hardware technologies. The introduction of the NCSA Mosaic web browser in 1993 – one of the first graphical web browsers – led to an explosion in web use. Marc Andreessen, the leader of the Mosaic team at NCSA, soon started his own company, named Netscape, and released the Mosaic-influenced Netscape Navigator in 1994, which quickly became the world’s most popular browser, accounting for 90% of all web use at its peak (see usage share of web browsers).

Microsoft responded with its browser Internet Explorer in 1995 (also heavily influenced by Mosaic), initiating the industry’s first browser war. Bundled with Windows, Internet Explorer gained dominance in the web browser market; Internet Explorer usage share peaked at over 95% by 2002. Opera debuted in 1996; although it has never achieved widespread use, having less than 1% browser usage share as of February 2009 according to Net Applications, having grown to 2.14 in April 2011 its Opera-mini version has an additive share, in April 2011 amounting to 1.11 % of overall browser use, but focused on the fast-growing mobile phone web browser market, being preinstalled on over 40 million phones. It is also available on several other embedded systems, including Nintendo’s Wii video game console. More…

Independent reviews of the best web hosting providers. The web hosting industry has spawned a broad range of niche markets over the years. Ranging from shared hosting to dedicated hosting, as well as all the hybrids in between, each type of web hosting presents its own set of pros and cons. Web hosting services are the key for any individual or business with aspirations of succeeding online.

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A graphics tablet (or digitizer, digitizing tablet, graphics pad, drawing tablet) is a computer input device that enables a user to hand-draw images and graphics, similar to the way a person draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the surface. Capturing data in this way, either by tracing or entering the corners of linear poly-lines or shapes is called digitizing.

A graphics tablet (also called pen pad or digitizer) consists of a flat surface upon which the user may “draw” or trace an image using an attached stylus, a pen-like drawing apparatus. The image generally does not appear on the tablet itself but, rather, is displayed on the computer monitor. Some tablets, however, come as a functioning secondary computer screen that you can interact with images directly by using the stylus. Some tablets are intended as a general replacement for a mouse as the primary pointing and navigation device for desktop computers.

History and background

The first electronic handwriting tablet was the Telautograph, patented by Elisha Gray in 1888. Elisha Gray is best known as a contemporaneous inventor of the telephone to Alexander Graham Bell. The first graphics tablet resembling contemporary tablets and used for handwriting recognition by a computer was the Stylator in 1957. Better known (and often mis-stated as the first digitizer tablet) is the RAND Tablet also known as theGrafacon (for Graphic Converter), introduced in 1964. The RAND Tablet employed a grid of wires under the surface of the pad that encoded horizontal and vertical coordinates in a small magnetic signal. The stylus would receive the magnetic signal, which could then be decoded back as coordinate information.

Other graphics tablets a commonly known as spark or acoustic tablets, used a stylus that generated clicks with a spark plug. The clicks were then triangulated by a series of microphones to locate the pen in space. The system was fairly complex and expensive, and the sensors were susceptible to interference by external noise. Digitizers were popularized in the mid 1970s and early 1980s by the commercial success of the ID (Intelligent Digitizer) and BitPad manufactured by the Summagraphics Corp. These digitizers were used as the input device for many high-endCAD (Computer Aided Design) systems as well as bundled with PC’s and PC based More…

Double data rate synchronous dynamic random access memory (DDR SDRAM) is a class of memory integrated circuits used in computers. DDR SDRAM (sometimes referred to as DDR1 SDRAM) has been superseded by DDR2 SDRAM and DDR3 SDRAM, neither of which are either forward or backward compatible with DDR SDRAM, meaning that DDR2 or DDR3 memory moduleswill not work in DDR equipped motherboards, and vice versa.

Compared to single data rate (SDR) SDRAM, the DDR SDRAM interface makes higher transfer rates possible by more strict control of the timing of the electrical data and clock signals. Implementations often have to use schemes such as phase-locked loops and self-calibration to reach the required timing accuracy.^[1][2] The interface uses double pumping (transferring data on both the rising and falling edges of the clock signal) to lower the clock frequency. One advantage of keeping the clock frequency down is that it reduces the signal integrity requirements on the circuit board connecting the memory to the controller. The name “double data rate” refers to the fact that a DDR SDRAM with a certain clock frequency achieves nearly twice the bandwidth of a single data rate (SDR) SDRAM running at the same clock frequency, due to this double pumping. More…

Thin film transistor liquid crystal display (TFT-LCD) is a variant of liquid crystal display (LCD) which uses thin-film transistor (TFT) technology to improve image quality (e.g., addressability, contrast). TFT LCD is one type of active matrix LCD, though all LCD-screens are based on TFT active matrix addressing. TFT LCDs are used in television sets, computer monitors, mobile phones, handheld video game systems, personal digital assistants, navigation systems, projectors.

Small liquid crystal displays as used in calculators and other devices have direct driven image elements – a voltage can be applied across one segment without interfering with other segments of the display. This is impractical for a large display with a large number of picture elements (pixels), since it would require millions of connections – top and bottom connections for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns, reducing the connection count from millions to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge applied to the pixel from draining between refreshes to the display image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers.

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process. Transistors take up only a small fraction of the area of each pixel; the rest of the silicon film is etched away to allow light to pass through. Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or view finders. Amorphous silicon-based TFTs are by far the most common due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and difficult to produce. More…

The term x86 refers to a family of instruction set architectures based on the Intel 8086 CPU. The 8086 was launched in 1978 as a fully 16-bit extension of Intel’s 8-bit based 8080 microprocessor and also introduced segmentation to overcome the 16-bit addressing barrier of such designs. The term x86 derived from the fact that early successors to the 8086 also had names ending in “86″. Many additions and extensions have been added to the x86 instruction set over the years, almost consistently with full backward compatibility. The architecture has been implemented in processors from Intel, Cyrix, AMD, VIA, and many others.

The term is not synonymous with IBM PC compatibility as this implies a multitude of other hardware; embedded systems as well as computers used x86 chips before the PC-compatible market started, some of them before the IBM PC itself.

As the term became common after the introduction of the 80386, it usually implies binary compatibility with the 32-bit instruction set of the 80386. This may sometimes be emphasized as x86-32to distinguish it either from the original 16-bit “x86-16″ or from the 64-bit x86-64. Although most x86 processors used in new personal computers and servers have 64-bit capabilities, to avoid compatibility problems with older computers or systems, the term x86-64 (or x64) is often used to denote 64-bit software, with the term x86 implying only 32-bit. More…

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, Mac OS X has been included with all new Macintosh computer systems. It is the successor to Mac OS 9, released in 1999, the final release of the “classic” Mac OS, which had been Apple’s primary operating system since 1984.

Mac OS X, whose X is the Roman numeral for 10 and is a prominent part of its brand identity, is a Unix-based graphical operating system, built on technologies developed at NeXTbetween the second half of the 1980s and Apple’s purchase of the company in late 1996. From its sixth release, Mac OS X v10.5 “Leopard” and onward, every release of Mac OS X gained UNIX 03 certification while running on Intel processors.

The first version released was Mac OS X Server 1.0 in 1999, and a desktop-oriented version, Mac OS X v10.0 “Cheetah” followed on March 24, 2001. Releases of Mac OS X are named after big cats: for example, Mac OS X v10.6 is usually referred to by Apple and users as “Snow Leopard”. The server edition, Mac OS X Server, is architecturally identical to its desktop counterpart, and includes tools to facilitate management of workgroups of Mac OS X machines, and to provide access to network services. These tools include a mail transfer agent, anLDAP server, a domain name server, and others. It is pre-loaded on Apple’s Xserve server hardware, but can be run on almost all of Apple’s current selling computer models.

Apple also produces specialized versions of Mac OS X for use on its consumer devices. iOS, which is based on Mac OS X, runs on the iPhone, iPod Touch, iPad, and the 2nd generation Apple TV. An unnamed variant of Mac OS X powered the 1st generation Apple TV.

Mac OS X is based upon the Mach kernel. Certain parts from FreeBSD’s and NetBSD’s implementation of Unix were incorporated in NeXTSTEP, the core of Mac OS X. NeXTSTEP was the object-oriented operating system developed by Steve Jobs’ company NeXT after he left Apple in 1985. While Jobs was away from Apple, Apple tried to create a “next-generation” OS through the Taligent, Copland and Gershwin projects, with little success. More…

Winamp is a media player for Windows-based PCs and Android devices, written by Nullsoft, now a subsidiary of AOL. It is proprietary freeware/shareware, multi-format, extensible with plug-ins and skins, and is noted for its graphical sound visualization, playlist, and media library features. Winamp was developed by American programmer Justin Frankel and Russian programmerDmitry Boldyrev while both were students at the University of Utah in 1997, and its popularity grew quickly, along with the developing trend of MP3 file-sharing.

Winamp supports music playback using MP3, MIDI, MOD, MPEG-1 audio layers 1 and 2, AAC, M4A, FLAC, WAV and WMA. Winamp was one of the first common music players on Windows to support playback of Ogg Vorbis by default.It supports gapless playback for MP3 and AAC, and Replay Gain for volume leveling across tracks. CD support includes playing and import music from audio CDs, optionally with CD-Text, and burning music to CDs. The standard version limits maximum burn speed and datarate; the “Pro” version removes these limitations.

Winamp supports playback of Windows Media Video and Nullsoft Streaming Video. For MPEG Video, AVI and other unsupported video types, Winamp uses Microsoft’s DirectShow API for playback, allowing playback of most of the video formats supported by Windows Media Player. 5.1 Surround sound is supported where formats and decoders allow. More…

A laptop (notebook) is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device (a touchpad, also known as a trackpad, and/or a pointing stick) and speakers into a single unit. A laptop is powered by mains electricity via an AC adapter, and can be used away from an outlet using a rechargeable battery. A laptop battery in new condition typically stores enough energy to run the laptop for three to five hours, depending on the computer usage, configuration and power management settings. When the laptop is plugged into the mains, the battery charges, whether or not the computer is running.

Portable computers, originally monochrome CRT-based and developing into the modern laptop, were originally considered to be a small niche market, mostly for specialized field applications such as the military, accountants and sales representatives. As portable computers became smaller, lighter, and cheaper and as screens became larger and of better quality, laptops became very widely used for all sorts of purposes. More…