THE INTERNET
The Internet is a new world. The Internet is not only "The Big Picture," it also offers a global perspective. By providing connectivity to anyone with a computer and a telephone line, the Internet is the networking breakthrough of our lifetime. It includes everything from universal e-mail to transactions between individuals and between companies. Of course, this now includes commerce as well as information exchanges and new directories (such as search engines) that provide phone book-style accessibility for digital communications.
Some of the most important results of this networking revolution are new forms of marketing and outreach, new connections between customers and collaborators, new sources for news and research, and opportunities for new kinds of distribution of products (as well as of information). But because the Internet is the broadest information super-highway, it lacks some of the security and privacy that's needed for the internal workings of business organizations. Advanced features like multimedia are also more likely to be limited because most individuals are still using dial-up connections and, as a result, have very limited data bandwidth.
INTRANET
Intranets are new kinds of internal networks. Think of "Intra" as it is used in Intramural sports. Intranets tend to resemble the architecture of a closed-circuit video network as opposed to the Internet which is more like broadcasting in terms of its reach. Intranets are used for more private communications, connectivity among work groups and larger organizations. For example, some companies use Intranets to offer corporate services such as benefits programs and other kinds of corporate communications. Also, Intranets enable information sharing that empowers employees who might otherwise be left "out of the loop." (See "Groupware" below.)
Because of their limited geographic range, Intranets offer more bandwidth, frequently Ethernet's 10Kbps or better. As a result of this bandwidth and the "closed loop" structure, more advanced networking features such as video and multimedia, as well as more technological control, are possible. For example, a company can specify that a specific web browser and even a specific version of that browser (licensed by the company) be used on its network. This enables a consistent and more dependable user experience than is possible on the Internet. Even Internet related services such as Pointcast can be customized for a particular company and its Intranet.
EXTRANETE
Extranets are a more complex implementation of the wired world. Just because an employee is telecommuting doesn't mean she shouldn't have access to the company Intranet. Sales people on the road are just as critical to a corporation's success as those who sit behind desks. And in today's world of virtual work groups, suppliers and other vendors are frequently critical members of the team and they may need an insider's degree of access. Extranet's provide these important networking "bridges" by combining the Internet with the Intranet.
By extending the corporate network to include the Internet, team members get the best of both worlds -- mobility with exclusivity. Because of the necessary security involved, Extranets frequently require the development of custom applications. For example, in order to give a remote sales person access to corporate sales statistics, the user needs remote access to a database that cannot be made visible to the competition. Most often, for something this sensitive, encryption is involved because password protection is not sufficient.
In most cases, Extranets do not involve high bandwidth applications like video and multimedia because of the limited bandwidth of remote users who most frequently use dial up connections.
Ethernet is the most widely-installed local area network ( LAN) technology. Specified in a standard, IEEE 802.3, Ethernet was originally developed by Xerox from an earlier specification called Alohanet (for the Palo Alto Research Center Aloha network) and then developed further by Xerox, DEC, and Intel. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. Ethernet is also used in wireless LANs. The most commonly installed Ethernet systems are called 10BASE-T and provide transmission speeds up to 10 Mbps. Devices are connected to the cable and compete for access using a Carrier Sense Multiple Access with Collision Detection (CSMA/CD ) protocol.
Fast Ethernet or 100BASE-T provides transmission speeds up to 100 megabits per second and is typically used for LAN backbone systems, supporting workstations with 10BASE-T cards. Gigabit Ethernet provides an even higher level of backbone support at 1000 megabits per second (1 gigabit or 1 billion bits per second). 10-Gigabit Ethernet provides up to 10 billion bits per second.
Ethernet was named by Robert Metcalfe, one of its developers, for the passive substance called "luminiferous (light-transmitting) ether" that was once thought to pervade the universe, carrying light throughout. Ethernet was so- named to describe the way that cabling, also a passive medium, could similarly carry data everywhere throughout the network.
2010年7月4日星期日
Perbezaan Antara 3 Topologi(Star,Bus,Ring)
Tpologi Bus
Tpologi jaringan bus meruapakan beberapa simpul/node dihubungkan dg jalur data (bus).topolgi ini menyediakan 1 saluran untuk komunikasisemua perangkat shgg setiap perangkat harus bergantian seluran tersebut.hanya ada 2perangkat yg saling berkomunikasi dalam 1 saat.tiap node dapat melakukan tugas-tugas dan operasi yg berbeda.Untuk mengifisiensi penggunaan jaringan digunukan metode CSMA/CD(Carrier Sense Multiplay Access/Collision Detected)yg mernguragi masa tenggang(saluran kosong)dg mendeteksi tabrakan informasi.
Keuntungan Topolgi Bus
1.Mengurangi kabel&jarak LAN tidak terbatas.
2.Biaya instalasi sgt murah.
3.Mudah untuk menambah atau mengurangkan kompuer &nod
Kekurangan Topologi Bus
1.Memerlukan terminator untuk kedua ujng kabel tulang belakang
2.Perlu pengulang (repeater0jika LAN jauh.
3.Jika kabel tulabg belakang (backbone)/mana-mana nodnya bermasalah rangkaian tidak dapat berfungsi.
Topologi Ring
Mempunyai satu titik kesalahan,terletak pd hub.jika pusat hub mengalami kegagalan,maka seluruh jaringan akan gagal beroperasi.Memerlukan alat pd central poin untuk membroadcast ulang atau pergantian traffic jaringan (switch network rraffic).Penempatan kabel yg diguib\nakan ring menggunakan desain yg sederhanh,pada topologi ring,setiap computer yg pertama.
Keuntungan Topologi Ring
1.Setiap computer hak akses yg sama terhadap token,sehingga tidak akan ada computer yg memonopoli jaringan.
2.Data yg mengalir dalam satu arah sehingga terjadinya collision dapat dihindarkan.
Kekurangan Topolgi ring
1.Apabila ada satu computer dlm ring yg gagal berfungsi,maka akan mempengaruhi keseluruhan jaringan.
2.Sulit mengatsi kerusakan di jaringan yg menggunakan topolgo ring.
3Menambah atau menguirangikomputer akan mengacaukaun jaringan.
Topologi Star
Dalam topologi star,semua kabel di hubungkan dr computer-computer ke lokasi pusat(central location),dimana semuanya rehubung ke suatu alat yg dinamakan hub
Keuntungan Topologi star
Cukup mudah untuk mengubah dan menambah computer kedalam jaringan yg menggunakan topologi star tanpa mengganggu aktivitas jaringan yg sedang berkangsung.Pusat dari jaringan star merupakan tempat yg baik untuk menentukan diagnosa kesalahan yg terjadi dalam jaringan.Kita dapat memakai beberapa tipe kabel didalam jaringan yg sama dg hub yg dapat mengakomodasi tipe kabel yg berbeda
Kekurangan Topologi star
Memepunyai satu titik kesalahan,terletak pd hub.Jika hub pusat mengalami kegagalan,maka seluruh jaringan akan gagal beroperasi.memerlukan alat pd central poin untuk membroadcast ulang ppergantian traffic jaringan (switch network traffic).
Topologi Mesh
Topologi Mesh adalah suatu bentuk hubungan antar perangkat,dimana perangkat terhubung secara langsung ke perangkat lainya yg ada didalam jaringan.Akibatnya,dalam topologi ini setiap perangkat dapat berlomunikasi langsung dgn parangkat yg dituju(dedicated links)
Keuntungan Topologi Mesh
Memiliki sifat Robust,yaitu apabila terjadi gangguan pada koneksi computer A dgn computer B karena ruasaknya kabel koneksi(links).Memudahkan proses identifikasi permasakahan pd saat terjadi kerusakan koneksi pd computer.
Kekurangan Topologi Mesh
Membutuhkan banyak kabel dan Port I/o.Semakin banyk computer didalam topologi mesh mk di[erlukan semakin banyak kabel links dan port I/O.Hal tersebut sekaligus jg mengindisikasikan bahwa topologi jenis ini membutuhkan biaya yg relative mahal.Karena setiap computer harus terkoneksi secara langsung dgn computer kainya mk instalasi dan konfigurasi menjadi sulit.
Tpologi jaringan bus meruapakan beberapa simpul/node dihubungkan dg jalur data (bus).topolgi ini menyediakan 1 saluran untuk komunikasisemua perangkat shgg setiap perangkat harus bergantian seluran tersebut.hanya ada 2perangkat yg saling berkomunikasi dalam 1 saat.tiap node dapat melakukan tugas-tugas dan operasi yg berbeda.Untuk mengifisiensi penggunaan jaringan digunukan metode CSMA/CD(Carrier Sense Multiplay Access/Collision Detected)yg mernguragi masa tenggang(saluran kosong)dg mendeteksi tabrakan informasi.
Keuntungan Topolgi Bus
1.Mengurangi kabel&jarak LAN tidak terbatas.
2.Biaya instalasi sgt murah.
3.Mudah untuk menambah atau mengurangkan kompuer &nod
Kekurangan Topologi Bus
1.Memerlukan terminator untuk kedua ujng kabel tulang belakang
2.Perlu pengulang (repeater0jika LAN jauh.
3.Jika kabel tulabg belakang (backbone)/mana-mana nodnya bermasalah rangkaian tidak dapat berfungsi.
Topologi Ring
Mempunyai satu titik kesalahan,terletak pd hub.jika pusat hub mengalami kegagalan,maka seluruh jaringan akan gagal beroperasi.Memerlukan alat pd central poin untuk membroadcast ulang atau pergantian traffic jaringan (switch network rraffic).Penempatan kabel yg diguib\nakan ring menggunakan desain yg sederhanh,pada topologi ring,setiap computer yg pertama.
Keuntungan Topologi Ring
1.Setiap computer hak akses yg sama terhadap token,sehingga tidak akan ada computer yg memonopoli jaringan.
2.Data yg mengalir dalam satu arah sehingga terjadinya collision dapat dihindarkan.
Kekurangan Topolgi ring
1.Apabila ada satu computer dlm ring yg gagal berfungsi,maka akan mempengaruhi keseluruhan jaringan.
2.Sulit mengatsi kerusakan di jaringan yg menggunakan topolgo ring.
3Menambah atau menguirangikomputer akan mengacaukaun jaringan.
Topologi Star
Dalam topologi star,semua kabel di hubungkan dr computer-computer ke lokasi pusat(central location),dimana semuanya rehubung ke suatu alat yg dinamakan hub
Keuntungan Topologi star
Cukup mudah untuk mengubah dan menambah computer kedalam jaringan yg menggunakan topologi star tanpa mengganggu aktivitas jaringan yg sedang berkangsung.Pusat dari jaringan star merupakan tempat yg baik untuk menentukan diagnosa kesalahan yg terjadi dalam jaringan.Kita dapat memakai beberapa tipe kabel didalam jaringan yg sama dg hub yg dapat mengakomodasi tipe kabel yg berbeda
Kekurangan Topologi star
Memepunyai satu titik kesalahan,terletak pd hub.Jika hub pusat mengalami kegagalan,maka seluruh jaringan akan gagal beroperasi.memerlukan alat pd central poin untuk membroadcast ulang ppergantian traffic jaringan (switch network traffic).
Topologi Mesh
Topologi Mesh adalah suatu bentuk hubungan antar perangkat,dimana perangkat terhubung secara langsung ke perangkat lainya yg ada didalam jaringan.Akibatnya,dalam topologi ini setiap perangkat dapat berlomunikasi langsung dgn parangkat yg dituju(dedicated links)
Keuntungan Topologi Mesh
Memiliki sifat Robust,yaitu apabila terjadi gangguan pada koneksi computer A dgn computer B karena ruasaknya kabel koneksi(links).Memudahkan proses identifikasi permasakahan pd saat terjadi kerusakan koneksi pd computer.
Kekurangan Topologi Mesh
Membutuhkan banyak kabel dan Port I/o.Semakin banyk computer didalam topologi mesh mk di[erlukan semakin banyak kabel links dan port I/O.Hal tersebut sekaligus jg mengindisikasikan bahwa topologi jenis ini membutuhkan biaya yg relative mahal.Karena setiap computer harus terkoneksi secara langsung dgn computer kainya mk instalasi dan konfigurasi menjadi sulit.
Network Topology
Network topology is defined as the interconnection of the various elements (links, nodes, etc.) of a computer network.[1][2] Network Topologies can be physical or logical. Physical Topology means the physical design of a network including the devices, location and cable installation. Logical topology refers to the fact that how data actually transfers in a network as opposed to its physical design.
Topology can be considered as a virtual shape or structure of a network. This shape actually does not correspond to the actual physical design of the devices on the computer network. The computers on the home network can be arranged in a circle shape but it does not necessarily mean that it presents a ring topology.
Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses graph theory. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical.
A Local Area Network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometrical shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.
Topology can be considered as a virtual shape or structure of a network. This shape actually does not correspond to the actual physical design of the devices on the computer network. The computers on the home network can be arranged in a circle shape but it does not necessarily mean that it presents a ring topology.
Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses graph theory. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical.
A Local Area Network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometrical shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.
Basic topology types
The study of network topology recognizes five basic topologies:
Bus topology
Star topology
Ring topology
Tree topology
Mesh topology
Bus
In local area networks where bus topology is used, each machine is connected to a single cable. Each computer or server is connected to the single bus cable through some kind of connector. A terminator is required at each end of the bus cable to pr ev ent the signal from bouncing back and forth on the bus cable. A signal from the source travels in both directions to all machines connected on the bus cable until it finds the MAC add ress or IP address on the network that is the intended recipient. If the machine address does not match the intended address for the data, the machine ignores the data. Alternatively, if the data doe s match the machine address, the data is accepted. Sinc e the bus topology consists of only one wire, it is rather inexpensive to implement when compared t o other topologies. However, the low cost of implementing the technol ogy is offse t by the high cost of managing the network. Additionally, since only one cable is utilized, it can be the single point of failure. If the netw ork cable breaks, the e ntire network will be down.
Star
In local area networks with a star topology, each network host is connected to a central hub. In contrast to the bus topology, the star topology connect s ea ch node to the hub with a point-to-point connection. All traffic that transverses the ne twork passes through the central hub. The hub acts as a signal booster or repeater. The star topology is considered the easiest topology to design and implement. An advantage of the star top ology is the simplicity of adding additional nodes. The primary disadvantage of the star topology is that the hub represents a single
Ring
In local area networks where the ring topology is used, each computer is connected to the network in a closed loop or ring. Each machine or computer has a unique address that is used for identification purposes. The signal passes throug h e ach machine or computer connected to the ring in one direction. Ring topologies typically utili ze a token passing scheme, used to control access to the network. By utilizing this scheme, only one machine can transmit on the network at a time. The machines or computers connected to the ring act as signal boosters or repeaters which strengthen the signals that transverse the network. The primary disadvantage of ring topology is the failure of one machine will cause the entire network to fail.[citation needed] 
Tree
Also known as a hierarchical network.
The type of network topology in which a central 'root' node (the top level of the hierarchy) is connected to one or more other nodes that are one level lower in the hierarchy (i.e., the second level) with a point-to-point link between each of the
second level nodes and the top level central 'root' node, while each of the second level nodes that are connected to the top level central 'root' node will also have one or more other nodes that are o
ne level lower in the hierarchy (i.e., the third level) connected to it, also with a point-to-point link, the top level central 'root' node being the only node tha
t has no other node above it in the hierarchy (The hierarchy of the tree is symmetrical.) Each node in the network having a specific fixed number, of nodes connected to it at the next lower l
evel in the hierarchy, the number, being referred to as the 'branching factor' of the hierarchical tree.
Mesh
The value of fully meshed networks is proportional to the exponent of the number of subscribers, assuming that communicating groups of any
two endpoints, up to and including all the endpoints, is approximated by Reed's Law.
The value of fully meshed networks is proportional to the exponent of the number of subscribers, assuming that communicating groups of any
two endpoints, up to and including all the endpoints, is approximated by Reed's Law.
Network architecture
Network architecture is the design of a communications network. It is a framework for the specification of a network's physical components and their functional organization and configuration, its operational principles and procedures, as well as data formats used in its operation.
In computing, the network architecture is a characteristics of a computer network. The most prominent architecture today is evident in the framework of the Internet, which is based on the Internet Protocol Suite.
In telecommunication, the specification of a network architecture may also include a detailed description of products and services delivered via a communications network, as well as detailed rate and billing structures under which services are compensated.
In distinct usage in distributed computing, network architecture is also sometimes used as a synonym for the structure and classification of distributed application architecture, as the participating nodes in a distributed application are often referred to as a network. For example, the applications architecture of the public switched telephone network (PSTN) has been termed the Advanced Intelligent Network. There are any number of specific classifications but all lie on a continuum between the dumb network (e.g., Internet) and the intelligent computer network (e.g., the telephone network). Other networks contain various elements of these two classical types to make them suitable for various types of applications. Recently the context aware network, which is a synthesis of the two, has gained much interest with its ability to combine the best elements of both.
In computing, the network architecture is a characteristics of a computer network. The most prominent architecture today is evident in the framework of the Internet, which is based on the Internet Protocol Suite.
In telecommunication, the specification of a network architecture may also include a detailed description of products and services delivered via a communications network, as well as detailed rate and billing structures under which services are compensated.
In distinct usage in distributed computing, network architecture is also sometimes used as a synonym for the structure and classification of distributed application architecture, as the participating nodes in a distributed application are often referred to as a network. For example, the applications architecture of the public switched telephone network (PSTN) has been termed the Advanced Intelligent Network. There are any number of specific classifications but all lie on a continuum between the dumb network (e.g., Internet) and the intelligent computer network (e.g., the telephone network). Other networks contain various elements of these two classical types to make them suitable for various types of applications. Recently the context aware network, which is a synthesis of the two, has gained much interest with its ability to combine the best elements of both.
Computer network
Computer networking is the engineering discipline concerned with the communication between computer systems or devices. A computer network is any set of computers or devices connected to each other with the ability to exchange data.[1] Computer networking is sometimes considered a sub-discipline of telecommunications, computer science, information technology and/or computer engineering since it relies heavily upon the theoretical and practical application of these scientific and engineering disciplines. The three types of networks are: the Internet, the intranet, and the extranet. Examples of different network methods are:
Local area network (LAN), which is usually a small network constrained to a small geographic area. An example of a LAN would be a computer network within a building.
Metropolitan area network (MAN), which is used for medium size area. examples for a city or a state.
Wide area network (WAN) that is usually a larger network that covers a large geographic area.
Wireless LANs and WANs (WLAN & WWAN) are the wireless equivalent of the LAN and WAN.All networks are interconnected to allow communication with a variety of different kinds of media, including twisted-pair copper wire cable, coaxial cable, optical fiber, power lines and various wireless technologies.[2] The devices can be separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the interconnections of the Internet[3]). Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs.[4]
Local area network (LAN), which is usually a small network constrained to a small geographic area. An example of a LAN would be a computer network within a building.
Metropolitan area network (MAN), which is used for medium size area. examples for a city or a state.
Wide area network (WAN) that is usually a larger network that covers a large geographic area.
Wireless LANs and WANs (WLAN & WWAN) are the wireless equivalent of the LAN and WAN.All networks are interconnected to allow communication with a variety of different kinds of media, including twisted-pair copper wire cable, coaxial cable, optical fiber, power lines and various wireless technologies.[2] The devices can be separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the interconnections of the Internet[3]). Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs.[4]
Network cards such as this one can receive data at high
rates over transmit and various types of network cables.This card is a 'Combo' card which supports three cabling standards.
History of computer networks
Before the advent of computer networks that were based upon some type of telecommunicationssystem, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behaviors seen in today's Internet were demonstrably present in the nineteenth century and arguably in even earlier networks using visual signals.
In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model at Dartmouth College in New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Linking output systems like teletypes to computers was an interest at the Advanced Research Projects Agency (ARPA) when, in 1962, J.C.R. Licklider was hired and developed a working group he called the "Intergalactic Network", a precursor to the ARPANet.
In 1964, researchers at Dartmouth developed the Dartmouth Time Sharing SystemMIT, a research group supported by General Electric and Bell Labs used a computer DEC's to route and manage telephone connections. for distributed users of large computer systems. The same year, at
Throughout the 1960s Leonard Kleinrock, Paul Baran and Donald Davies independently conceptualized and developed network systems which used datagrams or packets that could be used in a network between computer systems.
1965 Thomas Merrill and Lawrence G. Roberts created the first wide area network (WAN).
The first widely used PSTN switch that used true computer control was the Western Electric introduced in 1965.
In 1969 the University of California at Los Angeles, SRI (in Stanford), University of California at Santa Barbara, and the University of Utah were connected as the beginning of the ARPANET network using 50 kbit/s circuits. Commercial services using X.25 were deployed in 1972, and later used as an underlying infrastructure for expanding TCP/IP networks.
Computer networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from the researcher to the home user.
Today, computer networks are the core of modern communication. All modern aspects of the Public Switched Telephone Network (PSTN) are computer-controlled, and telephony increasingly runs over the Internet Protocol, although not necessarily the public Internet. The scope of communication has increased significantly in the past decade, and this boom in communications would not have been possible without the progressively advancing computer network.
Before the advent of computer networks that were based upon some type of telecommunicationssystem, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behaviors seen in today's Internet were demonstrably present in the nineteenth century and arguably in even earlier networks using visual signals.
In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model at Dartmouth College in New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Linking output systems like teletypes to computers was an interest at the Advanced Research Projects Agency (ARPA) when, in 1962, J.C.R. Licklider was hired and developed a working group he called the "Intergalactic Network", a precursor to the ARPANet.
In 1964, researchers at Dartmouth developed the Dartmouth Time Sharing SystemMIT, a research group supported by General Electric and Bell Labs used a computer DEC's to route and manage telephone connections. for distributed users of large computer systems. The same year, at
Throughout the 1960s Leonard Kleinrock, Paul Baran and Donald Davies independently conceptualized and developed network systems which used datagrams or packets that could be used in a network between computer systems.
1965 Thomas Merrill and Lawrence G. Roberts created the first wide area network (WAN).
The first widely used PSTN switch that used true computer control was the Western Electric introduced in 1965.
In 1969 the University of California at Los Angeles, SRI (in Stanford), University of California at Santa Barbara, and the University of Utah were connected as the beginning of the ARPANET network using 50 kbit/s circuits. Commercial services using X.25 were deployed in 1972, and later used as an underlying infrastructure for expanding TCP/IP networks.
Computer networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from the researcher to the home user.
Today, computer networks are the core of modern communication. All modern aspects of the Public Switched Telephone Network (PSTN) are computer-controlled, and telephony increasingly runs over the Internet Protocol, although not necessarily the public Internet. The scope of communication has increased significantly in the past decade, and this boom in communications would not have been possible without the progressively advancing computer network.
2010年5月12日星期三
operating system
What is an Operating System???
The operating system is the core software component of your computer. It performs many functions and is, in very basic terms, an interface between your computer and the outside world. In the section about hardware, a computer is described as consisting of several component parts including your monitor, keyboard, mouse, and other parts. The operating system provides an interface to these parts using what is referred to as "drivers". This is why sometimes when you install a new printer or other piece of hardware, your system will ask you to install more software called a driver.
What does a driver do???
A driver is a specially written program which understands the operation of the device it interfaces to, such as a printer, video card, sound card or CD ROM drive. It translates commands from the operating system or user into commands understood by the the component computer part it interfaces with. It also translates responses from the component computer part back to responses that can be understood by the operating system, application program, or user. The below diagram gives a graphical depiction of the interfaces between the operating system and the computer component.
The operating system is the core software component of your computer. It performs many functions and is, in very basic terms, an interface between your computer and the outside world. In the section about hardware, a computer is described as consisting of several component parts including your monitor, keyboard, mouse, and other parts. The operating system provides an interface to these parts using what is referred to as "drivers". This is why sometimes when you install a new printer or other piece of hardware, your system will ask you to install more software called a driver.
What does a driver do???
A driver is a specially written program which understands the operation of the device it interfaces to, such as a printer, video card, sound card or CD ROM drive. It translates commands from the operating system or user into commands understood by the the component computer part it interfaces with. It also translates responses from the component computer part back to responses that can be understood by the operating system, application program, or user. The below diagram gives a graphical depiction of the interfaces between the operating system and the computer component.
secondary storage
Secondary storage technology refers to storage devices and storage media that are not always directly accessible by a computer. This differs from primary storage technology, such as an internal hard drive, which is constantly available.
Examples of secondary storage devices include external hard drives, USB flash drives, and tape drives. These devices must be connected to a computer's external I/O ports in order to be accessed by the system. They may or may not require their own power supply.
Examples of secondary storage media include recordable CDs and DVDs, floppy disks, and removable disks, such as Zip disks and Jaz disks. Each one of these types of media must be inserted into the appropriate drive in order to be read by the computer. While floppy disks and removable disks are rarely used anymore, CDs and DVDs are still a popular way to save and transfer data.
Because secondary storage technology is not always accessible by a computer, it is commonly used for archival and backup purposes. If a computer stops functioning, a secondary storage device may be used to restore a recent backup to a new system. Therefore, if you use a secondary storage device to backup your data, make sure you run frequent backups and test the data on a regular basis.
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2010年5月5日星期三
primary storage
1) Primary storage, also known as main storage or memory, is the main area in a computer in which data is stored for quick access by the computer's processor. On today's smaller computers, especially personal computers and workstations, the term random access memory (RAM) - or just memory - is used instead of primary or main storage, and the hard disk, diskette, CD, and DVD collectively describe secondary storage or auxiliary storage.
The terms main storage and auxiliary storage originated in the days of the mainframe computer to distinguish the more immediately accessible data storage from storage that required input/output operations. An earlier term for main storage was core in the days when the main data storage contained ferrite cores.
The terms main storage and auxiliary storage originated in the days of the mainframe computer to distinguish the more immediately accessible data storage from storage that required input/output operations. An earlier term for main storage was core in the days when the main data storage contained ferrite cores.
2) Primary storage is sometimes used to mean storage for data that is in active use in contrast to storage that is used for backup purposes. In this usage, primary storage is mainly the secondary storage referred to in meaning 1. (It should be noted that, although these two meanings conflict, the appropriate meaning is usually apparent from the context.)
2010年4月20日星期二
IP address
An identifier for a computer
or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP address.
Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to the Internet requires using registered IP addresses (called Internet addresses) to avoid duplicates.
The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. Four regional Internet registries -- ARIN, RIPE NCC, LACNIC and APNIC -- assign Internet addresses from the following three classes.
Class A - supports 16 million hosts on each of 126 networks
Class B - supports 65,000 hosts on each of 16,000 networks
Class C - supports 254 hosts on each of 2 million networks
The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied to adoption of IPv6.
Also see Understanding IP Addressing in the Did You Know . . .? section of Webopedia.
•E-mail this definition to a colleague•
For internet.com pages about IP address . Also check out the following links!
TCP/IP and IPX routing tutorial This tutorial supplies information on setting up a relatively simple WAN-connected internetwork or Internet-connected LAN. Includes explanations of IP addresses, classes, netmasks, subnetting, routing, several example networks, and a basic explanation of IPX routing
Webopedia's "Did You Know...?" Section Use this Webopedia knowledge section for an in-depth overview of specific technologies and occurrences in the areas of Computer Science, The Internet, and Computer Hardware and Software.
Webopedia's Quick Reference Section Use this Webopedia reference section for information on common Internet and computer facts and occurrences.
Webopedia's Tech Support Area Read the descriptions of each tech support Web site below, and choose the one that best suits your needs. We offer these links to help users get the tech support they need.
LearnToSubnet.ComAn educational course on addressing TCP/IP Networks that includes IP Addresses and Subnetting. Topics include: Binary Math, IP Addressing (IP Address), Subnet Mask, and Custom Subnet Mask.
Addressing
Internet
Routing
APIPA
APNIC
ARIN
ARP
ccTLD
CIDR
Class C network
DDR
DNS
domain name
dynamic DNS
failover
FQDN
hot potato routing
IANA
Internet
InterNIC
IP spoofing
martian address
Mobile IP
NAT
ping
port scanning
RIPE NCC
root server system
Give Us YourFeedback
or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP address.
Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to the Internet requires using registered IP addresses (called Internet addresses) to avoid duplicates.
The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. Four regional Internet registries -- ARIN, RIPE NCC, LACNIC and APNIC -- assign Internet addresses from the following three classes.
Class A - supports 16 million hosts on each of 126 networks
Class B - supports 65,000 hosts on each of 16,000 networks
Class C - supports 254 hosts on each of 2 million networks
The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied to adoption of IPv6.
Also see Understanding IP Addressing in the Did You Know . . .? section of Webopedia.
•E-mail this definition to a colleague•
For internet.com pages about IP address . Also check out the following links!
TCP/IP and IPX routing tutorial This tutorial supplies information on setting up a relatively simple WAN-connected internetwork or Internet-connected LAN. Includes explanations of IP addresses, classes, netmasks, subnetting, routing, several example networks, and a basic explanation of IPX routing
Webopedia's "Did You Know...?" Section Use this Webopedia knowledge section for an in-depth overview of specific technologies and occurrences in the areas of Computer Science, The Internet, and Computer Hardware and Software.
Webopedia's Quick Reference Section Use this Webopedia reference section for information on common Internet and computer facts and occurrences.
Webopedia's Tech Support Area Read the descriptions of each tech support Web site below, and choose the one that best suits your needs. We offer these links to help users get the tech support they need.
LearnToSubnet.ComAn educational course on addressing TCP/IP Networks that includes IP Addresses and Subnetting. Topics include: Binary Math, IP Addressing (IP Address), Subnet Mask, and Custom Subnet Mask.
Addressing
Internet
Routing
APIPA
APNIC
ARIN
ARP
ccTLD
CIDR
Class C network
DDR
DNS
domain name
dynamic DNS
failover
FQDN
hot potato routing
IANA
Internet
InterNIC
IP spoofing
martian address
Mobile IP
NAT
ping
port scanning
RIPE NCC
root server system
Give Us YourFeedback
IP address
Definitions of IP address on the Web:
An Internet Protocol (IP) address is a numerical label that is assigned to devices participating in a computer network utilizing the Internet ...en.wikipedia.org/wiki/IP_address
(Internet Protocol address) A number assigned to each computer's or other device's network interface(s) which are active on a network supporting ...en.wiktionary.org/wiki/IP_address
A unique numeric identifier for a computer on a network.library.gnome.org/users/user-guide/stable/glossary-1.html.en
The network address of a computer system or host.www.primode.com/glossary.html
An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the ...www.techniqueweb.com/terminology.php
A binary value used by the IP protocol to determine how to deliver packets to their destination hosts. See the entry dotted-quad for a common representation of these addresses.tangentsoft.net/wskfaq/glossary.html
Internet Protocol address – a computer network addressvisibleprocrastinations.wordpress.com/2007/07/06/videoconference-glossary-of-terms/
Every machine that is on the Internet has a unique IP number - if a machine does not have an IP number, it is not really on the Internet. ...www.buyyourdot.com/glossary.php
Numeric code that uniquely identifies a particular computer on the Internet.www.luc.edu/its/security/pci_glossary.shtml
Internet Protocol Address, a unique number assigned to every device connected to the Internet.www.headland.co.uk/pages/glossary
a unique number which identifies a computer and its location on the internet. Some of the online services at the University of Kent use the IP ...www.kent.ac.uk/library/support/a-z/glossary.html
Also called an Internet address. The unique address for each computer on the Internet. The IP address appears as a set of four numbers separated by periods. The numbers indicate the domain, the network, the subnetwork and the host computer. ...www.valenciacc.edu/lrcwest/lis2004/glossary.htm
A set of numbers used for a computer or device to acknowledge a website address.www.legalinternetmarketing.com/seo-glossary.html
Any computing device that uses the Internet must be assigned an Internet or IP address. All workstations on a given IP network use the same IP network number, and each workstation has a unique IP host address and an optional subnetwork number. ...www.telesysglobal.com/data_glossary.html
A method of locating a physical resource like a computer or digital camera on a TCP/IP computer networkwww.videoanalytics.org/pages/terminology.html
Find definitions of IP address in: Chinese (Simplified) Chinese (Traditional) Czech Dutch English French German Italian Portuguese Romanian Russian Spanish all languages
An Internet Protocol (IP) address is a numerical label that is assigned to devices participating in a computer network utilizing the Internet ...en.wikipedia.org/wiki/IP_address
(Internet Protocol address) A number assigned to each computer's or other device's network interface(s) which are active on a network supporting ...en.wiktionary.org/wiki/IP_address
A unique numeric identifier for a computer on a network.library.gnome.org/users/user-guide/stable/glossary-1.html.en
The network address of a computer system or host.www.primode.com/glossary.html
An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the ...www.techniqueweb.com/terminology.php
A binary value used by the IP protocol to determine how to deliver packets to their destination hosts. See the entry dotted-quad for a common representation of these addresses.tangentsoft.net/wskfaq/glossary.html
Internet Protocol address – a computer network addressvisibleprocrastinations.wordpress.com/2007/07/06/videoconference-glossary-of-terms/
Every machine that is on the Internet has a unique IP number - if a machine does not have an IP number, it is not really on the Internet. ...www.buyyourdot.com/glossary.php
Numeric code that uniquely identifies a particular computer on the Internet.www.luc.edu/its/security/pci_glossary.shtml
Internet Protocol Address, a unique number assigned to every device connected to the Internet.www.headland.co.uk/pages/glossary
a unique number which identifies a computer and its location on the internet. Some of the online services at the University of Kent use the IP ...www.kent.ac.uk/library/support/a-z/glossary.html
Also called an Internet address. The unique address for each computer on the Internet. The IP address appears as a set of four numbers separated by periods. The numbers indicate the domain, the network, the subnetwork and the host computer. ...www.valenciacc.edu/lrcwest/lis2004/glossary.htm
A set of numbers used for a computer or device to acknowledge a website address.www.legalinternetmarketing.com/seo-glossary.html
Any computing device that uses the Internet must be assigned an Internet or IP address. All workstations on a given IP network use the same IP network number, and each workstation has a unique IP host address and an optional subnetwork number. ...www.telesysglobal.com/data_glossary.html
A method of locating a physical resource like a computer or digital camera on a TCP/IP computer networkwww.videoanalytics.org/pages/terminology.html
Find definitions of IP address in: Chinese (Simplified) Chinese (Traditional) Czech Dutch English French German Italian Portuguese Romanian Russian Spanish all languages
colour code
Color code
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Wikimedia Commons has media related to: Color code
Color code (as a system for displaying information by using different colors) may refer to:
Bottled gases
Color codes in three-phase electric power (electrical wiring)
Electronic color code
Web colors for HTML color codes
25-pair color code
Color coding of optical fibers
Color codes of fire extinguishers
Hanky code
Jumper cables
Traffic lights
Navigation lights, sea marks and characteristic lights
Ribbon colors see: Category:Ribbon symbolism
The Homeland Security Advisory System color code in the United States
Utility color codes
ColorCode 3D stereo image system using blue/amber viewing glasses
[edit] See also
Color-coding, an algorithmic technique in computer science
This disambiguation page lists articles associated with the same title.If an internal link led you here, you may wish to change the link to point directly to the intended article.
Retrieved from "http://en.wikipedia.org/wiki/Color_code"
Categories: Disambiguation pages Color codes
Hidden categories: All article disambiguation pages All disambiguation pages
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Wikimedia Commons has media related to: Color code
Color code (as a system for displaying information by using different colors) may refer to:
Bottled gases
Color codes in three-phase electric power (electrical wiring)
Electronic color code
Web colors for HTML color codes
25-pair color code
Color coding of optical fibers
Color codes of fire extinguishers
Hanky code
Jumper cables
Traffic lights
Navigation lights, sea marks and characteristic lights
Ribbon colors see: Category:Ribbon symbolism
The Homeland Security Advisory System color code in the United States
Utility color codes
ColorCode 3D stereo image system using blue/amber viewing glasses
[edit] See also
Color-coding, an algorithmic technique in computer science
This disambiguation page lists articles associated with the same title.If an internal link led you here, you may wish to change the link to point directly to the intended article.
Retrieved from "http://en.wikipedia.org/wiki/Color_code"
Categories: Disambiguation pages Color codes
Hidden categories: All article disambiguation pages All disambiguation pages
colour code
Definitions of Colour code on the Web:
Color code (as a system for displaying information by using different colors) may refer to: *Bottled gases *Color codes in three-phase electric power (electrical wiring) *Electronic color code *Web colors for HTML color codes *25-pair color code *Color coding of optical fibers *Color codes of ...en.wikipedia.org/wiki/Colour_code
Any system where colours are used to categorize elements of sets; To mark items with a colour code as a means of sortingen.wiktionary.org/wiki/colour_code
Color code (as a system for displaying information by using different colors) may refer to: *Bottled gases *Color codes in three-phase electric power (electrical wiring) *Electronic color code *Web colors for HTML color codes *25-pair color code *Color coding of optical fibers *Color codes of ...en.wikipedia.org/wiki/Colour_code
Any system where colours are used to categorize elements of sets; To mark items with a colour code as a means of sortingen.wiktionary.org/wiki/colour_code
straight cable
What are Straight and Crossover cableCommon Ethernet network cable are straight and crossover cable. This Ethernet network cable is made of 4 pair high performance cable that consists twisted pair conductors that used for data transmission. Both end of cable is called RJ45 connector.
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The cable can be categorized as Cat 5, Cat 5e, Cat 6 UTP cable. Cat 5 UTP cable can support 10/100 Mbps Ethernet network, whereas Cat 5e and Cat 6 UTP cable can support Ethernet network running at 10/100/1000 Mbps. You might heard about Cat 3 UTP cable, it's not popular anymore since it can only support 10 Mbps Ethernet network.
Straight and crossover cable can be Cat3, Cat 5, Cat 5e or Cat 6 UTP cable, the only difference is each type will have different wire arrangement in the cable for serving different purposes.
Straight Cable
You usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to:
1) Connect a computer to a switch/hub's normal port.2) Connect a computer to a cable/DSL modem's LAN port. 3) Connect a router's WAN port to a cable/DSL modem's LAN port.4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network)5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.
If you need to check how straight cable looks like, it's easy. Both side (side A and side B) of cable have wire arrangement with same color. Check out different types of straight cable that are available in the market here.
Crossover Cable
Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to:
1) Connect 2 computers directly.2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network)3) Connect 2 switches/hubs by using normal port in both switches/hubs.
In you need to check how crossover cable looks like, both side (side A and side B) of cable have wire arrangement with following different color . Have a look on these crossover cables if you plan to buy one. You can also find more network cable choices and information from Comtrad Cables.
In case you need to make a crossover cable yourself! You can use this crimper to do it.
Lastly, if you still not sure which type of cable to be used sometimes, try both cables and see which works.
Note: If there is auto MDI/MDI-X feature support on the switch, hub, network card or other network devices, you don't have to use crossover cable in the situation which I mentioned above. This is because crossover function would be enabled automatically when it's needed
google_protectAndRun("ads_core.google_render_ad", google_handleError, google_render_ad);
The cable can be categorized as Cat 5, Cat 5e, Cat 6 UTP cable. Cat 5 UTP cable can support 10/100 Mbps Ethernet network, whereas Cat 5e and Cat 6 UTP cable can support Ethernet network running at 10/100/1000 Mbps. You might heard about Cat 3 UTP cable, it's not popular anymore since it can only support 10 Mbps Ethernet network.
Straight and crossover cable can be Cat3, Cat 5, Cat 5e or Cat 6 UTP cable, the only difference is each type will have different wire arrangement in the cable for serving different purposes.
Straight Cable
You usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to:
1) Connect a computer to a switch/hub's normal port.2) Connect a computer to a cable/DSL modem's LAN port. 3) Connect a router's WAN port to a cable/DSL modem's LAN port.4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network)5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.
If you need to check how straight cable looks like, it's easy. Both side (side A and side B) of cable have wire arrangement with same color. Check out different types of straight cable that are available in the market here.
Crossover Cable
Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to:
1) Connect 2 computers directly.2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network)3) Connect 2 switches/hubs by using normal port in both switches/hubs.
In you need to check how crossover cable looks like, both side (side A and side B) of cable have wire arrangement with following different color . Have a look on these crossover cables if you plan to buy one. You can also find more network cable choices and information from Comtrad Cables.
In case you need to make a crossover cable yourself! You can use this crimper to do it.
Lastly, if you still not sure which type of cable to be used sometimes, try both cables and see which works.
Note: If there is auto MDI/MDI-X feature support on the switch, hub, network card or other network devices, you don't have to use crossover cable in the situation which I mentioned above. This is because crossover function would be enabled automatically when it's needed
cross cable
A crossover cable is a cable that is used to interconnect two computers by "crossing over" (reversing) their respective PIN contacts. Either an RS-232C or a telephone jack connection is possible. A crossover cable is sometimes known as a null modem. Possible reasons to connect two computers directly to each other include:Playing a game competitively (one person at each computer) with fast response time
Testing one computer by examining its behavior at the other computer
Saving the cost of a hub when you want to interconnect two devices in the same home or office
2010年3月29日星期一
ICT SECTOR IN MALAYSIA
ICT Sector in Malaysia
The last two decades in Malaysia has been considered to be the era of wireless communications being led by two major trends: the outburst of wireless access communications - offering mobility to the telephone users and the mobile multimedia, and the increasing number of mobile communications subscribers.
Broadband penetration rate has increased from 10,9 for every 100 households in 2006, to 33,2 as of March 3, 2010, whereas the mobile phone penetration rate has breached the 100% threshold (per 100 inhabitants) in Q1 this year, and expected to reach 108,1% by Q1 2010 (Q4 2009: 106,2%)
Transformation to Internet Protocol Era
Meanwhile, the physical work for the High Speed Broadband (HSBB) project has begun in May 2009, with its retail services expected to be rolled out in some parts of the country by March 24, 2010. This RM 11,3 billion project, which is part-funded by the Malaysian government, is supposed to offer bandwidth at network speeds of 10Mbps where 1,3 million premises in the country will be covered under the project within the next 2-3 years.
This project is widely seen as instrumental in transforming the country's telecommunications infrastructure into the Internet Protocal era, where households and businesses will be getting broadband network access for triple play services (voice, video and internet). For example, there is a plan to move the country into digital TV era, with analogue swiff-off planned in 2015.
The overall Malaysian telecommunications industry has a market size of more than RM 40 million, whereas the network telecommunication market is said to be worth around RM 5 billion with a compounded annual growth rate of more than 50%. This sector will continue to represent one of the most important arenas of research and expansion in the ICT industry in Malaysia.
The last two decades in Malaysia has been considered to be the era of wireless communications being led by two major trends: the outburst of wireless access communications - offering mobility to the telephone users and the mobile multimedia, and the increasing number of mobile communications subscribers.
Broadband penetration rate has increased from 10,9 for every 100 households in 2006, to 33,2 as of March 3, 2010, whereas the mobile phone penetration rate has breached the 100% threshold (per 100 inhabitants) in Q1 this year, and expected to reach 108,1% by Q1 2010 (Q4 2009: 106,2%)
Transformation to Internet Protocol Era
Meanwhile, the physical work for the High Speed Broadband (HSBB) project has begun in May 2009, with its retail services expected to be rolled out in some parts of the country by March 24, 2010. This RM 11,3 billion project, which is part-funded by the Malaysian government, is supposed to offer bandwidth at network speeds of 10Mbps where 1,3 million premises in the country will be covered under the project within the next 2-3 years.
This project is widely seen as instrumental in transforming the country's telecommunications infrastructure into the Internet Protocal era, where households and businesses will be getting broadband network access for triple play services (voice, video and internet). For example, there is a plan to move the country into digital TV era, with analogue swiff-off planned in 2015.
The overall Malaysian telecommunications industry has a market size of more than RM 40 million, whereas the network telecommunication market is said to be worth around RM 5 billion with a compounded annual growth rate of more than 50%. This sector will continue to represent one of the most important arenas of research and expansion in the ICT industry in Malaysia.
ICT IN MALAYSIA
Malaysia Case Study
Malaysia is, in many ways, an atypical country. It is hard to categorize and neither developed nor developing, or both, depending on the region. It is characterized by great disparities within the country and faces the dilemma of ensuring its regional and global competitiveness in ICT while at the same time ensuring equitable ICT access in rural areas. Thus there are projects such as the Multimedia Super Corridor (MSC), a government-driven initiative to develop a Malaysian Silicon Valley, as well as the Internet Desa, a program to install Internet centers in rural areas.
The Internet is developing rapidly in Malaysia, helped by some of the lowest dial-up rates in the world (around 40 US cents per hour). As a result, there were some 1.2 million Internet subscribers—the majority residential—at the end of 2000 with an estimated 15 per cent of the population using the Internet. Broadband access is predominantly via leased lines. Asynchronous Digital Subscriber Line (ADSL) technology is being tested but is not yet widely available. Pay television service is mainly through Direct-to-Home satellite technology so cable modem access is not an option in Malaysia. Another option for broadband access is through fixed wireless but there are a number of technical and regulatory challenges to overcome in this area.
An ITU team, consisting of Vanessa Gray, Michael Minges and Lucy Firth, carried out field research for Malaysia from 2-6 April 2001. The Malaysian Communications and Multimedia Commission (CMC)—the country’s Information and Communication Technology (ICT) regulator—served as counterpart and organized meetings with relevant government and industry organization.
See also the Malaysia Broadband Case Study, preparedby the ITU’s Strategy and Policy Unit (SPU).
Malaysia Case Study
PDF file (1.6 Mb)
PDF file zipped (1.4 Mb)
See Malaysia photos
Malaysia is, in many ways, an atypical country. It is hard to categorize and neither developed nor developing, or both, depending on the region. It is characterized by great disparities within the country and faces the dilemma of ensuring its regional and global competitiveness in ICT while at the same time ensuring equitable ICT access in rural areas. Thus there are projects such as the Multimedia Super Corridor (MSC), a government-driven initiative to develop a Malaysian Silicon Valley, as well as the Internet Desa, a program to install Internet centers in rural areas.
The Internet is developing rapidly in Malaysia, helped by some of the lowest dial-up rates in the world (around 40 US cents per hour). As a result, there were some 1.2 million Internet subscribers—the majority residential—at the end of 2000 with an estimated 15 per cent of the population using the Internet. Broadband access is predominantly via leased lines. Asynchronous Digital Subscriber Line (ADSL) technology is being tested but is not yet widely available. Pay television service is mainly through Direct-to-Home satellite technology so cable modem access is not an option in Malaysia. Another option for broadband access is through fixed wireless but there are a number of technical and regulatory challenges to overcome in this area.
An ITU team, consisting of Vanessa Gray, Michael Minges and Lucy Firth, carried out field research for Malaysia from 2-6 April 2001. The Malaysian Communications and Multimedia Commission (CMC)—the country’s Information and Communication Technology (ICT) regulator—served as counterpart and organized meetings with relevant government and industry organization.
See also the Malaysia Broadband Case Study, preparedby the ITU’s Strategy and Policy Unit (SPU).
Malaysia Case Study
PDF file (1.6 Mb)
PDF file zipped (1.4 Mb)
See Malaysia photos
2010年3月23日星期二
ict
introduction - what is ICT?
You see the letters ICT everywhere - particularly in education. But what does it mean? Read our brief introduction to this important and fast-changing subject.
ICT is an acronym that stands for Information Communications Tecnology
However, apart from explaining an acronym, there is not a universally accepted defininition of ICT? Why? Because the concepts, methods and applications involved in ICT are constantly evolving on an almost daily basis. Its difficult to keep up with the changes - they happen so fast.
Lets focus on the three words behind ICT:
- INFORMATION- COMMUNICATIONS- TECHNOLOGY
A good way to think about ICT is to consider all the uses of digital technology that already exist to help individuals, businesses and organisations use information.
ICT covers any product that will store, retrieve, manipulate, transmit or receive information electronically in a digital form. For example, personal computers, digital television, email, robots.
So ICT is concerned with the storage, retrieval, manipulation, transmission or receipt of digital data. Importantly, it is also concerned with the way these different uses can work with each other.
In business, ICT is often categorised into two broad types of product: -
(1) The traditional computer-based technologies (things you can typically do on a personal computer or using computers at home or at work); and
(2) The more recent, and fast-growing range of digital communication technologies (which allow people and organisations to communicate and share information digitally)
Let's take a brief look at these two categories to demonstrate the kinds of products and ideas that are covered by ICT:
Traditional Computer Based Technologies
These types of ICT include:
Application
Use
Standard Office Applications - Main Examples
Word processing
E.g. Microsoft Word: Write letters, reports etc
Spreadsheets
E.g. Microsoft Excel; Analyse financial information; calculations; create forecasting models etc
Database software
E.g. Oracle, Microsoft SQL Server, Access; Managing data in many forms, from basic lists (e.g. customer contacts through to complex material (e.g. catalogue)
Presentation software
E.g. Microsoft PowerPoint; make presentations, either directly using a computer screen or data projector. Publish in digital format via email or over the Internet
Desktop publishing
E.g. Adobe Indesign, Quark Express, Microsoft Publisher; produce newsletters, magazines and other complex documents.
Graphics software
E.g Adobe Photoshop and Illustrator; Macromedia Freehand and Fireworks; create and edit images such as logos, drawings or pictures for use in DTP, web sites or other publications
Specialist Applications - Examples (there are many!)
Accounting package
E.g. Sage, Oracle; Manage an organisation's accounts including revenues/sales, purchases, bank accounts etc. A wide range of systems is available ranging from basic packages suitable for small businesses through to sophisticated ones aimed at multinational companies.
Computer Aided Design
Computer Aided Design (CAD) is the use of computers to assist the design process. Specialised CAD programs exist for many types of design: architectural, engineering, electronics, roadways
Customer Relations Management (CRM)
Software that allows businesses to better understand their customers by collecting and analysing data on them such as their product preferences, buying habits etc. Often linked to software applications that run call centres and loyalty cards for example.
Traditional Computer Based Technologies
The C part of ICT refers to the communication of data by electronic means, usually over some distance. This is often achieved via networks of sending and receiving equipment, wires and satellite links.
The technologies involved in communication tend to be complex. You certainly don't need to understand them for your ICT course. However, there are aspects of digital communications that you needs to be aware of. These relate primarily to the types of network and the ways of connecting to the Internet. Let's look at these two briefly (further revision notes provide much more detail to support your study).
Internal networks
Usually referred to as a local area network (LAN), this involves linking a number of hardware items (input and output devices plus computer processing) together within an office or building.
The aim of a LAN is to be able to share hardware facilities such as printers or scanners, software applications and data. This type of network is invaluable in the office environment where colleagues need to have access to common data or programmes.
External networks
Often you need to communicate with someone outside your internal network, in this case you will need to be part of a Wide Area Network (WAN). The Internet is the ultimate WAN - it is a vast network of networks.ICT in a Broader Context
Your ICT course will almost certainly cover the above examples of ICT in action, perhaps focusing on the use of key applications such as spreadsheets, databases, presentation, graphics and web design software.
It will also consider the following important topics that deal with the way ICT is used and managed in an organisation:
- The nature of information (the "I" in ICT); this covers topics such as the meaning and value of information; how information is controlled; the limitations of ICT; legal considerations
- Management of information - this covers how data is captured, verified and stored for effective use; the manipulation, processing and distribution of information; keeping information secure; designing networks to share information
- Information systems strategy - this considers how ICT can be used within a business or organisation as part of achieving goals and objectives
As you can see, ICT is a broad and fast-changing subject. We hope our free study materials (revision notes, quizzes, presentations etc) will help you master IT!
You see the letters ICT everywhere - particularly in education. But what does it mean? Read our brief introduction to this important and fast-changing subject.
ICT is an acronym that stands for Information Communications Tecnology
However, apart from explaining an acronym, there is not a universally accepted defininition of ICT? Why? Because the concepts, methods and applications involved in ICT are constantly evolving on an almost daily basis. Its difficult to keep up with the changes - they happen so fast.
Lets focus on the three words behind ICT:
- INFORMATION- COMMUNICATIONS- TECHNOLOGY
A good way to think about ICT is to consider all the uses of digital technology that already exist to help individuals, businesses and organisations use information.
ICT covers any product that will store, retrieve, manipulate, transmit or receive information electronically in a digital form. For example, personal computers, digital television, email, robots.
So ICT is concerned with the storage, retrieval, manipulation, transmission or receipt of digital data. Importantly, it is also concerned with the way these different uses can work with each other.
In business, ICT is often categorised into two broad types of product: -
(1) The traditional computer-based technologies (things you can typically do on a personal computer or using computers at home or at work); and
(2) The more recent, and fast-growing range of digital communication technologies (which allow people and organisations to communicate and share information digitally)
Let's take a brief look at these two categories to demonstrate the kinds of products and ideas that are covered by ICT:
Traditional Computer Based Technologies
These types of ICT include:
Application
Use
Standard Office Applications - Main Examples
Word processing
E.g. Microsoft Word: Write letters, reports etc
Spreadsheets
E.g. Microsoft Excel; Analyse financial information; calculations; create forecasting models etc
Database software
E.g. Oracle, Microsoft SQL Server, Access; Managing data in many forms, from basic lists (e.g. customer contacts through to complex material (e.g. catalogue)
Presentation software
E.g. Microsoft PowerPoint; make presentations, either directly using a computer screen or data projector. Publish in digital format via email or over the Internet
Desktop publishing
E.g. Adobe Indesign, Quark Express, Microsoft Publisher; produce newsletters, magazines and other complex documents.
Graphics software
E.g Adobe Photoshop and Illustrator; Macromedia Freehand and Fireworks; create and edit images such as logos, drawings or pictures for use in DTP, web sites or other publications
Specialist Applications - Examples (there are many!)
Accounting package
E.g. Sage, Oracle; Manage an organisation's accounts including revenues/sales, purchases, bank accounts etc. A wide range of systems is available ranging from basic packages suitable for small businesses through to sophisticated ones aimed at multinational companies.
Computer Aided Design
Computer Aided Design (CAD) is the use of computers to assist the design process. Specialised CAD programs exist for many types of design: architectural, engineering, electronics, roadways
Customer Relations Management (CRM)
Software that allows businesses to better understand their customers by collecting and analysing data on them such as their product preferences, buying habits etc. Often linked to software applications that run call centres and loyalty cards for example.
Traditional Computer Based Technologies
The C part of ICT refers to the communication of data by electronic means, usually over some distance. This is often achieved via networks of sending and receiving equipment, wires and satellite links.
The technologies involved in communication tend to be complex. You certainly don't need to understand them for your ICT course. However, there are aspects of digital communications that you needs to be aware of. These relate primarily to the types of network and the ways of connecting to the Internet. Let's look at these two briefly (further revision notes provide much more detail to support your study).
Internal networks
Usually referred to as a local area network (LAN), this involves linking a number of hardware items (input and output devices plus computer processing) together within an office or building.
The aim of a LAN is to be able to share hardware facilities such as printers or scanners, software applications and data. This type of network is invaluable in the office environment where colleagues need to have access to common data or programmes.
External networks
Often you need to communicate with someone outside your internal network, in this case you will need to be part of a Wide Area Network (WAN). The Internet is the ultimate WAN - it is a vast network of networks.ICT in a Broader Context
Your ICT course will almost certainly cover the above examples of ICT in action, perhaps focusing on the use of key applications such as spreadsheets, databases, presentation, graphics and web design software.
It will also consider the following important topics that deal with the way ICT is used and managed in an organisation:
- The nature of information (the "I" in ICT); this covers topics such as the meaning and value of information; how information is controlled; the limitations of ICT; legal considerations
- Management of information - this covers how data is captured, verified and stored for effective use; the manipulation, processing and distribution of information; keeping information secure; designing networks to share information
- Information systems strategy - this considers how ICT can be used within a business or organisation as part of achieving goals and objectives
As you can see, ICT is a broad and fast-changing subject. We hope our free study materials (revision notes, quizzes, presentations etc) will help you master IT!
Virus
A virus (from the Latin virus meaning toxin or poison) is a small infectious agent that can replicate only inside the cells of other organisms. Most viruses are too small to be seen directly with a light microscope. Viruses infect all types of organisms, from animals and plants to bacteria and archaea.[1] Since the initial discovery of tobacco mosaic virus by Martinus Beijerinck in 1898,[2] about 5,000 viruses have been described in detail,[3] although there are millions of different types.[4] Viruses are found in almost every ecosystem on Earth and these minute structures are the most abundant type of biological entity.[5][6] The study of viruses is known as virology, a sub-specialty of microbiology.
Unlike prions and viroids, viruses consist of two or three parts: all viruses have genes made from either DNA or RNA, long molecules that carry genetic information; all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell. (Viroids do not have a protein coat and prions contain no RNA or DNA.) Viruses vary from simple helical and icosahedral shapes to more complex structures. Most viruses are about one hundred times smaller than an average bacterium. The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity.[7]
Viruses spread in many ways; plant viruses are often transmitted from plant to plant by insects that feed on sap, such as aphids, while animal viruses can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors. Influenza viruses are spread by coughing and sneezing. The norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal-oral route and are passed from person to person by contact, entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood.
Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artificially acquired immunity to the specific viral infection. However, some viruses including those causing HIV and viral hepatitis evade these immune responses and result in chronic infections. Microorganisms also have defences against viral infection, such as restriction modification systems which restrict the growth of viruses. Antibiotics have no effect on viruses, but several antiviral drugs have been developed.
Unlike prions and viroids, viruses consist of two or three parts: all viruses have genes made from either DNA or RNA, long molecules that carry genetic information; all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell. (Viroids do not have a protein coat and prions contain no RNA or DNA.) Viruses vary from simple helical and icosahedral shapes to more complex structures. Most viruses are about one hundred times smaller than an average bacterium. The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity.[7]
Viruses spread in many ways; plant viruses are often transmitted from plant to plant by insects that feed on sap, such as aphids, while animal viruses can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors. Influenza viruses are spread by coughing and sneezing. The norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal-oral route and are passed from person to person by contact, entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood.
Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artificially acquired immunity to the specific viral infection. However, some viruses including those causing HIV and viral hepatitis evade these immune responses and result in chronic infections. Microorganisms also have defences against viral infection, such as restriction modification systems which restrict the growth of viruses. Antibiotics have no effect on viruses, but several antiviral drugs have been developed.
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