Operating System (OS).

Operating System (OS).
Operating System is a program. That acts as an intermediatly between a user of computer and the computer hardware. The purpose of Operating System is to Provide environmental in which the user can execute the Program. An Operating System is similar to government. The component of compurer system. Systems are hardware, software and datas. The Operating System provides the means for the uses of resources in the Operation of the computer system. The Operating System perform no useful function by itself. If simply Provides and enviromental with in which other program can do successful work.

Modes of operation.

Modes of operation.

wireless network interface controller WNIC is a network card which connects to a radiobased computer network, unlike a regular network interface controller NIC which connects to a wirebased network such as token ring or ethernet. A WNIC, just like a NIC, works on the Layer and Layer of the OSI Model. A WNIC is an essential component for wireless desktop computer. This card uses an antenna to communicate through microwaves. A WNIC in a desktop computer usually is connected using the PCI bus. Other connectivity options are USB and PC card. Integrated WNICs are also available, typically in Mini PCIPCI Express Mini Card form.In an infrastructure mode network the WNIC needs an access point all data is transferred using the access point as the central hub. All wireless nodes in an infrastructure mode network connect to an access point. All nodes connecting to the access point must have the same service set identifier SSID as the access point, and if the access point is enabled with WEP they must have the same WEP key or other authentication parameters.

In an adhoc mode network the WNIC does not require an access point, but rather can directly interface with all other wireless nodes directly. All the nodes in an adhoc network must have the same channel and SSID.NICs are designed around the IEEE . standard which sets out lowlevel specifications for how all wireless networks operate. Earlier interface controllers are usually only compatible with earlier variants of the standard, while newer cards support both current and old standards.Wireless range may be substantially affected by objects in the way of the signal and by the quality of the antenna. Large electrical appliances, such as a refrigerators, fuse boxes, metal plumbing, and air conditioning units can block a wireless network signal. The theoretical maximum range is only reached under ideal circumstances and true effective range is typically about half of the theoretical range. Specifically, the maximum throughput speed is only achieved at extremely close range less than feet . m or so at the outer reaches of a devices effective range, speed may decrease to around Mbits before it drops out altogether.

Wireless network interface card.

Wireless network interface card.

WNICs are designed around the IEEE . standard which sets out lowlevel specifications for how all wireless networks operate. Earlier interface controllers are usually only compatible with earlier variants of the standard, while newer cards support both current and old standards.Wireless range may be substantially affected by objects in the way of the signal and by the quality of the antenna. Large electrical appliances, such as a refrigerators, fuse boxes, metal plumbing, and air conditioning units can block a wireless network signal. The theoretical maximum range is only reached under ideal circumstances and true effective range is typically about half of the theoretical range. Specifically, the maximum throughput speed is only achieved at extremely close range less than feet . m or so at the outer reaches of a devices effective range, speed may decrease to around Mbits before it drops out altogether. The reason is that wireless devices dynamically negotiate the top speed at which they can communicate without dropping too many data packets.

In computer networking, a Media Access Control address MAC address or Ethernet Hardware Address EHA, hardware address, adapter address or physical address is a quasiunique identifier assigned to most network adapters or network interface cards NICs by the manufacturer for identification. If assigned by the manufacturer, a MAC address usually encodes the manufacturers registered identification number.Although intended to be a permanent and globally unique identification, it is possible to change the MAC address on most of todays hardware, an action often referred to as MAC spoofing. Three numbering spaces, managed by the Institute of Electrical and Electronics Engineers IEEE, are in common use for formulating a MAC address MAC, EUI, and EUI. The IEEE claims trademarks on the names EUI and EUI, where EUI stands for Extended Unique Identifier.A host cannot determine a priori from the MAC address of another host whether that host is on the same OSI Layer network segment as the sending host or a network segment bridged to that network segment.

Network interface controller.

Network interface controller.

A MAC Address is a unique bit network hardware identifier that is burned into a ROM chip on the NIC to identify that device on the network. The first bits is called the Organizationally Unique Identifier OUI and is largely manufacturer dependent. Each OUI allows for ,, Unique NIC Addresses.Smaller manufacturers that do not have a need for over unique NIC addresses may opt to purchase an Individual Address Block IAB instead. An IAB consists of the bit OUI, plus a bit extension taken from the potential NIC portion of the MAC addressA wireless network interface controller WNIC is a network card which connects to a radiobased computer network, unlike a regular network interface controller NIC which connects to a wirebased network such as token ring or ethernet. A WNIC, just like a NIC, works on the Layer and Layer of the OSI Model.

A WNIC is an essential component for wireless desktop computer. This card uses an antenna to communicate through microwaves. A WNIC in a desktop computer usually is connected using the PCI bus. Other connectivity options are USB and PC card. In an infrastructure mode network the WNIC needs an access point all data is transferred using the access point as the central hub. All wireless nodes in an infrastructure mode network connect to an access point. All nodes connecting to the access point must have the same service set identifier SSID as the access point, and if the access point is enabled with WEP they must have the same WEP key or other authentication parameters.In an adhoc mode network the WNIC does not require an access point, but rather can directly interface with all other wireless nodes directly. All the nodes in an adhoc network must have the same channel and SSID.

Network interface controller.

Network interface controller.

There are four techniques used to transfer data, the NIC may use one or more of these techniques.Polling is where the microprocessor examines the status of the peripheral under program control.Programmed IO is where the microprocessor alerts the designated peripheral by applying its address to the systems address bus.Interruptdriven IO is where the peripheral alerts the microprocessor that its ready to transfer data.DMA is where the intelligent peripheral assumes control of the system bus to access memory directly. This removes load from the CPU but requires a separate processor on the card.A network card typically has a twisted pair, BNC, or AUI socket where the network cable is connected, and a few LEDs to inform the user of whether the network is active, and whether or not there is data being transmitted on it. Network Cards are typically available in Mbits varieties. This means they can support a transfer rate of , or Megabits per second.

A Network Interface Controller NIC is a hardware interface that handles and allows a network capable device access to a computer network such as the internet. The NIC has a ROM chip that has a unique Media Access Control MAC Address burned into it. The MAC address identifies the vendor and the serial number of the NIC which is unique to the card. Every NIC has a unique MAC address which identifies it on the LAN. The NIC exists on both the Physical Layer Layer and the Data Link Layer Layer of the OSI model.Sometimes the word controller and card is used interchangeably when talking about networking because the most common NIC is the Network Interface Card. Although card is more commonly used, it is in less encompassing. The controller may take the form of a network card that is installed inside a computer, or it may refer to an embedded component as part of a computer motherboard, a router, expansion card, printer interface, or a USB device.

Network Card.

Network Card.

A Network card, Network Adapter, LAN Adapter or NIC network interface card is a piece of computer hardware designed to allow computers to communicate over a computer network. It is both an OSI layer physical layer and layer data link layer device, as it provides physical access to a networking medium and provides a lowlevel addressing system through the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly.Although other network technologies exist, Ethernet has achieved nearubiquity since the mids. Every Ethernet network card has a unique bit serial number called a MAC address, which is stored in ROM carried on the card. Every computer on an Ethernet network must have a card with a unique MAC address. No two cards ever manufactured share the same address. This is accomplished by the Institute of Electrical and Electronics Engineers IEEE, which is responsible for assigning unique MAC addresses to the vendors of network interface controllers.

Whereas network cards used to be expansion cards that plug into a computer bus, the low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard. These either have Ethernet capabilities integrated into the motherboard chipset, or implemented via a low cost dedicated Ethernet chip, connected through the PCI or the newer PCI express bus. A separate network card is not required unless multiple interfaces are needed or some other type of network is used. Newer motherboards may even have dual network Ethernet interfaces builtin.The card implements the electronic circuitry required to communicate using a specific physical layer and data link layer standard such as Ethernet or token ring. This provides a base for a full network protocol stack, allowing communication among small groups of computers on the same LAN and largescale network communications through routable protocols, such as IP.

Printer.

Printer.

In computing, a printer is a peripheral which produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most newer printers, a USB cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time.
In addition, a few modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit, and can function as photocopiers. Printers that include non-printing features are sometimes called Multifunction Printers (MFP), Multi-Function Devices (MFD), or All-In-One (AIO) printers. Most MFPs include printing, scanning, and copying among their features. A Virtual printer is a piece of computer software whose user interface and API resemble that of a printer driver, but which is not connected with a physical computer printer.

Speakers.

Speakers.

Computer speakers, or multimedia speakers, are external speakers, commonly equipped with a low-power internal amplifier. The standard audio connection is a 3.5mm (1/8 inch) stereo jack plug often colour-coded lime green (following the PC 99 standard) for computer sound cards. A plug and socket for a two-wire (signal and ground) coaxial cable that is widely used to connect analog audio and video components. Also called a "phono connector," rows of RCA sockets are found on the backs of stereo amplifiers and numerous A/V products. The prong is 1/8" thick by 5/16" long. A few use an RCA connector for input. There are also USB speakers which are powered from the 5 volts at 200 milliamps provided by the USB port, allowing about half a watt of output power.
Computer speakers range widely in quality and in price. The computer speakers typically packaged with computer systems are small plastic boxes with mediocre sound quality. Some of the slightly better computer speakers have equalization features such as bass and treble controls, improving their sound quality somewhat.
The internal amplifiers require an external power source, known as a 'wall-wart'. More sophisticated computer speakers may have a 'subwoofer' unit, to enhance bass output, and these units usually include the power amplifiers both for the bass speaker, and the small 'satellite' speakers.
Some computer displays have rather basic speakers built-in. Laptops come with integrated speakers. Unfortunately the tight restriction on space inevitable in laptops means these speakers unavoidably produce low-quality sound.

Mouse.

Mouse.

In computing, 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.

Keyboard.

Keyboard.

In computing, a keyboard is an input device, partially modeled after the typewriter keyboard, which uses an arrangement of buttons or keys, which act as mechanical levers or electronic switches. A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands.
In normal usage, the keyboard is used to type text and numbers into a word processor, text editor or other program. In a modern computer, the interpretation of keypresses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all keypresses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations. A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine.

Power Supply.

Power Supply.

A power supply unit (PSU) is the component that supplies power to the other components in a computer. More specifically, a power supply unit is typically designed to convert general-purpose alternating current (AC) electric power from the mains (100-127V in North America, parts of South America, Japan, and Taiwan; 220-240V in most of the rest of the world) to usable low-voltage DC power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input voltage automatically, or are able to accept any voltage between those limits.
The most common computer power supplies are built to conform with the ATX form factor. This enables different power supplies to be interchangeable with different components inside the computer. ATX power supplies also are designed to turn on and off using a signal from the motherboard, and provide support for modern functions such as the standby mode available in many computers. The most recent specification of the ATX standard PSU as of mid-2008 is version 2.31.

Monitor.

Monitor.

A monitor or display is a piece of electrical equipment which displays images generated by devices such as computers, without producing a permanent record. The monitor comprises the actual display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD), while older monitors use a cathode ray tube (CRT).

DVD-ROM & DVD.

DVD-ROM & DVD.
A Digital Versatile Disk — Read Only Memory, or DVD-ROM, is a media storage disk that closely resembles a CD or compact disk. The major difference is that the DVD-ROM is formatted to hold far more data. There are various kinds of DVDs, but the DVD-ROM refers to a read-only disk, or a disk that cannot be written over. Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM (Read Only Memory) has data that can only be read and not written; DVD-R and DVD+R can record data only once, and then function as a DVD-ROM; DVD-RW, DVD+RW, and DVD-RAM can both record and erase data multiple times. The wavelength used by standard DVD lasers is 650 nm; thus, the light has a red color.
DVD Video and DVD Audio discs refer to properly formatted and structured video and audio content, respectively. Other types of DVDs, including those with video content, may be referred to as DVD Data discs.
As next-generation High Definition, more advanced optical formats (such as Blu-ray Disc) also use a disc identical in some aspects, the original DVD is occasionally given the retronym SD DVD (for standard definition). However, the trademarked HD DVD discs have been discontinued since Blu-ray absorbed their market share.

CD-ROM.

CD-ROM.

CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer. While the compact disc format was originally designed for music storage and playback, the 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data.
Five years later CD-ROM drives were being introduced on to computers. In 1994, they called a computer with a CD-ROM a Multimedia computer since it could play music and specially coded videos. Companies like Creative Technologies created a Sound Blaster multimedia upgrade kit which at the time gave the user a CD-ROM Drive with driver, a sound card and speakers. This in 1994 was a $200 product. Windows 95 in 1995 was introduced on either 10, 3.5-inch disks or 1 CD-ROM.
CD-ROMs are popularly used to distribute computer software, including games and multimedia applications, though any data can be stored (up to the capacity limit of a disc). Some CDs hold both computer data and audio with the latter capable of being played on a CD player, while data (such as software or digital video) is only usable on a computer (such as PC CD-ROMs). These are called enhanced CDs.
Although many people use lowercase letters in this acronym, proper presentation is in all capital letters with a hyphen between CD and ROM. It was also suggested by some, especially soon after the technology was first released, that CD-ROM was an acronym for "Compact Disc read-only-media", or that it was a more "correct" definition. This was not the intention of the original team who developed the CD-ROM, and common acceptance of the "memory" definition is now almost universal. This is probably in no small part due to the widespread use of other "ROM" acronyms such as Flash-ROMs and EEPROMs where "memory" is usually the correct term.

Floppy Disk Drive.

Floppy Disk Drive.

A floppy disk is a data storage medium that is composed of a disk of thin, flexible (Floppy) magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which is another term for a (non removable type of) hard disk drive. Invented by IBM, floppy disks in 8-inch (200 mm), 5¼-inch (133.35 mm), and 3½-inch (90 mm) formats enjoyed many years as a popular and ubiquitous form of data storage and exchange, from the mid-1970s to the late 1990s. While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment,[2] they have now been largely superseded by USB flash drives, External Hard Drives, CD-ROMs, DVD-ROMs, and Memory cards.

Hard Disk Drive.

Hard Disk Drive.

A hard disk drive is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, "drive" refers to a device distinct from its medium, such as a tape drive and its tape, or a floppy disk drive and its floppy disk. Early HDDs had removable media; however, an HDD today is typically a sealed unit (except for a filtered vent hole to equalize air pressure) with fixed media. A Hard disk drive also known Hard disk, Hard drive and HDD.

Sound Card.

Sound Card.

A sound card is a computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education, and entertainment (games). Many computers have sound capabilities built in, while others require additional expansion cards to provide for audio capability. Sound card also Known as Audio card.

Video Card.

Video Card.

The video card is an expansion card that allows the computer to send graphical information to a video display device such as a monitor or projector. A video card, also known as a graphics accelerator card, display adapter or graphics card. Some video cards offer added functions, such as video capture, TV tuner adapter, MPEG-2 and MPEG-4 decoding, FireWire, light pen, TV output, or the ability to connect multiple monitors.
A misconception regarding high end video cards is that they are strictly used for video games. High end video cards have a much broader range of capability; for example, they play a very important role for graphic designers and 3D animators, who tend to require optimum displays as well as faster rendering. Video hardware can be integrated on the mainboard, as it often happened with early computers; in this configuration it was sometimes referred to as a video controller or graphics controller.

Processor or CPU.

Processor or CPU.

A CPU (Central Processing Unit) or processor is an electronic circuit that can execute computer programs. This topic has been in use in the computer industry at least since the early 1960s (Weik 1961). The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation has remained much the same.
Early CPUs were custom-designed as a part of a larger, sometimes one-of-a-kind, computer. However, this costly method of designing custom CPUs for a particular application has largely given way to the development of mass-produced processors that are made for one or many purposes. This standardization trend generally began in the era of discrete transistor mainframes and minicomputers and has rapidly accelerated with the popularization of the integrated circuit (IC). The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers. Both the miniaturization and standardization of CPUs have increased the presence of these digital devices in modern life far beyond the limited application of dedicated computing machines. Modern microprocessors appear in everything from automobiles to cell phones to children's toys.

Random Access Memory.

Random Access Memory.

Random Access Memory (RAM)is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order (i.e., at random). The word random thus refers to the fact that any piece of data can be returned in a constant time, regardless of its physical location and whether or not it is related to the previous piece of data. RAM Used to provide temporary storage of information.

Types of RAM

Dynamic Random Access Memory (DRAM).
Static Random Access Memory (SRAM).

Dynamic Random Access Memory (DRAM).

Dynamic random access memory (DRAM) is stores each bit of data in a separate capacitor within an integrated circuit. Since real capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory.
The advantage of DRAM is its structural simplicity: only one transistor and a capacitor are required per bit, compared to four transistors in SRAM. This allows DRAM to reach very high density.

Static Random Access Memory (SRAM).

Static Random Access Memory (SRAM) is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM (DRAM), it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit. SRAM exhibits data remanence, but is still volatile in the conventional sense that data is eventually lost when the memory is not powered.

What is Mother Board?

What is Mother Board?

A motherboard is the central printed circuit board (PCB) in some complex electronic systems, such as modern personal computers.

The motherboard hold the following computer hardware subcomponents.

Random Access Memory (RAM).
Processor.
Video Card.
Sound Card.

What is Computer Hardware?

What is Computer Hardware?

The computer hardware refers to the various electronic components that are required for you to use a computer along with the hardware components inside the computer case. As you know your computer equipment is made of several common components.
The main computer box.

> Mother Board.
> Hard Disk Drive.
> Floppy Disk Drive.
> CD ROM or DVD ROM.
> Monitor.
> Power Supply.
> Keyboard.
> Mouse.
> Speakers.
> Printer.

What is Computer?

What is Computer?

A computer is a machine that manipulates data according to a set of instructions.
Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century (1940–1945). These were the size of a large room, consuming as much power as several hundred modern personal computers. Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into a wristwatch, and can be powered by a watch battery. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". The embedded computers found in many devices from MP3 players to fighter aircraft and from toys to industrial robots are however the most numerous.
The ability to store and execute lists of instructions called programs makes computers extremely versatile, distinguishing them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore computers ranging from a mobile phone to a supercomputer are all able to perform the same computational tasks, given enough time and storage capacity.