Network Computer

Selasa, 18 Mei 2010

Computer network is a collection of computers, printers and other equipment connected in unity. Information and data moving through wires or wireless computer network allowing users can exchange documents and data, print on the same printer and together using hardware / software that is connected to the network. Each computer, printer or peripherals connected to the network called a node. A computer network can have two, tens, thousands or even millions of nodes.

History of Network Computer

Computer Network was born in 1940 in america from a computer model 1 development project at bell labs and research group led by Harvad University Prof. H. Aiken. At First the project simply wanted to use a computer device that must be used together. to do some processing without much waste of time made the process of sucessive blank (batch processing), so some program can be run in a computer with the rules of the queue

In the year 1950 whe the types of computers began to grow until the creation of a super computer, a computer must serveral terminals (see picture 1) for the distribution was found in the concept or time based process know as TSS (Time Sharing System), for the first time from network (network) computer application. At TSS system several terminals connected in series to a host computer. In the process of TSS began to appear to blend computer technology and telecomunications technology that was originally developed indepedently.

picture a computer network model of TSS

Entered the 1970s more and more demands of work piled up and the price seemed expensive than the computer device in the distribution process and make the concept in this concept some host do a great job in pararell to serve several terminal that are connected in series in each host computer. In the process of distribution is requeired deep integration between the computer and telecommunitations technology, becouse in addition to the process that must be distributed, shall serve all host computers in a single terminal the terminal in a single command from the central computer.

picture 2 model of distribution processing computer network

Basically every computer in network that functions as client and server. but there is a network that has a dedicated computer as a server and the other as a client. Thare is also a computer that has no sepecial function as a server only. thus, bused on its function then there are two types of computer network :

Client-server

Namely Computer network a dedicated computer as server. A service can be provided by one ore more computer. domain such as www.detik.com server by many web server computer. There are also many services provided by a single computer, exsamples are jtk.polban.ac.id server which is a single computer with multi service is email server, web server file servers database servers and others.

Peer-to-peer

Namely computer networks where each host can be also be a client and server simultaneously. for example in file sharing between computers on the windows network neightbourhood network have five computers ( we give the name of A, B, C, D and E) that give the right of acess to the files they have. At one point A to assess the file share of B named data_value.xls and also give access to files soal_uas.doc C. When accessing a file from B to A then A is functioning as a client and when a give access to the files to C then A is functioning as a server. Both functions were performed by A the same time, such networks are called peer to peer.

Types of computer networks

Generally a computer network is divided into five types namely :

1. LAN ( Local Area Network )

Computer network whose network only covers a small area, such as campus computer network, building, office, in homes, schools or smaller, today most LAN based on IEEE 802.3 ethernet technologies use the device switches, whice have a data trasfer speed 10 or 100 Mbit/s. In addition to Ethernet technology, current technology, 802.11b (often called Wi-fi) is also often used to form a LAN. Places that provide LAN connectivity with Wi-fi technology, commonly called hotspots.

2. MAN ( Metropolitan Area network )

Metropolitan area network, or abbreviated with MAN. A network residing in a city with high-speed data transfer 2 KB and is basically a version LAN MAN larger and usually use the same technology with a LAN. MAN could include corporate offices are situated near or also a town and can be used for private purposes (private) or public. MAN capable of supporting voice and data, it can even connect with a cable TV network.

3. Wide Area Network (WAN)

mempuyai a computer network such a great distance area computer networks between regions, cities or even countries, but this requires the network routers and public communications channels.

4. Internet

Common computer system, which is connected globally and use TCP / IP as the packet exchange protocol (packet switching communication protocol). The largest internet series called the Internet. How to connect with kaedah series is called internetworking.

5. Wireless Networking

is a wireless network that uses radio frequency for communication between computers and finally the access point that is the basis of two-way radio transiver typically work in the bandwidth of 2.4 GHz (802.11b, 802.11g) or 5 GHz (802.11a). Most equipment has the qualifications Wi-Fi, IEEE 802.11b or IEEE 802.11g accommodation and offers several levels of security such as WEP or WPA and.

Computer network topology

Computer network topology design is the shape both physically and logically that is used to build a computer network. There are three basic topology of computer networks, namely the following.

1. BUS Topology


2. Topology TokenRING


3. STAR Topology