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.

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.

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.