EDUCATIONAL INFORMATICS

EDUCATIONAL INFORMATICS

                        Informatics is a branch of information science, and of computer science, that focuses on the study of information. It includes the science of Information, the practice of information processing, and the engineering of Information systems. Informatics studies the structure, algorithms, behaviour, and interactions of natural and artificial systems that store, process, access and communicate information. A practitioner of informatics may be called an informatician.

                        The term informatics was coined in 1957 by the German computer scientist, Karl Steinbuch, as a combination of information and automation to describe the science of automatic information processing.

                        The advancement of information technologies has led to the study of informatics that has computational, cognitive and social aspects. Informatics is broadly defined as the science concerned with gathering, manipulating, storing, retrieving and classifying recorded information. There are many terms derived from informatics. They include bioinformatics, educational informatics, legal informatics, neuro informatics etc.

     EDUCATIONAL INFORMATICS

                        Educational Informatics is a new and broad field of study that represent  the blend of aspects of information science, computing education, instructional systems technology and learning sciences. It is a sub- field of informatics. The term which got popularised since 2004, mainly focuses on computer applications, systems and networks that supports researches in education. It is based on information science, computer science and education. It is distinct from Informatics Education, which relates more to the practice of teaching/ learning about informatics, rather than the use of information science and technology in the support of teaching and learning.

COMPUTER NETWORK

                        A computer network is a collection of independent computer systems and devices interconnected by communication channels that facilitate data communication and resource sharing. Each participating computer system is called a terminal or a node.

                        Computer Networking requires a mix of computer hardware and computer software. Major components of computer network include at least two computer servers or client workstations, a Network Interface Card (NIC), communication media/cables, network operating system, hub/switch, routers and gateways.

MAJOR BENEFITS OF COMPUTER NETWORKS

§  Resource sharing: The goal here is to make all programs, data and equipment available to anyone on the network irrespective of the physical location of the resource and the user.

§  Reliability: the goal here is to provide high reliability by having alternative sources of supply.

§  Cost factor: Small computers have a much better price/ performance ratio than large ones. Mainframes are ten times faster than the fastest single chip microprocessors, but they cost a thousand times more. This imbalance has caused many system designers to build systems consisting of powerful personal computers, one per user, with data kept on one or more shared file server machines.

§  Increased performance: The computer network has the ability to increase system performance gradually as the work load grows by adding more processors. With central mainframes, when the system is full, it must be replaced by a large one, usually at great expense and with even greater disruption to the users.

§  Increased storage capacity: As there is more than one computer on a network which can easily share files, the issue of storage capacity gets resolved to a great extent. One can also design a storage server on the network in order to have a huge storage capacity.

§  Communication medium: a computer network can provide a powerful communication medium among widely separated people. Electronic mail and video conference make it easy for people to communicate.

  Following are some of the major disadvantages of computer networks.

§  Security issues: One of the major drawbacks of computer networks is the security issues involved. Computer hackers can get authorised access to a computer by using different tools. In case of big organisations, various network security softwares are used to prevent the theft of any confidential and classified data.

§  Rapid spread of computer viruses: If any computer system in a network gets affected by computer virus, there is a possible threat of other systems getting   affected too. Viruses get spread on a network easily because of the interconnectivity of workstations.

§  Expensive set up: The initial set up cost of a computer network can be high depending on the number of computers to be connected. Devices such as routers, hubs, switches, NICs are also quite expensive.

§  Dependency on the main file server: In case the main file server of a computer network breaks down, the system becomes useless. In case of big networks, the file server should be a powerful computer, which often makes it expensive.

LOCAL AREA NETWORK (LAN)

                   A Local Area Network (LAN) is digital communication system capable of interconnecting a large number of computers, terminals and other peripheral devices within a limited geographical area, typically, 1 km across. LANs normally operate within a compact area such as office building or a campus and is owned by the using organisations. The configuration of a LAN can be ring, star or simply devices attached along a length of cable. In LAN, transmission channels generally use coaxial or fibre optic cables and special interface units rather than telephone lines and modems. The two main purposes of LAN are to link computers within an organisation or campus so that they may share expensive peripheral devices, for example, high- speed printers or magnetic disks holding the database, and to allow these computers to communicate with each other.

A LAN consist of the following software

Ø Network management software or a network operating system. Some popular network operating systems are:

§  Novel Netware

§  Windows NT Server

§  Windows 2000

§  Linux

Ø Application software capable of supporting network access.

§  Server Software: A file server is server software that can process file related requests from the client workstations.

§  Client Software: This software runs on the client nodes and allows requests to be sent to the server and to receive back the result.

WORKING OF LAN

                        A node sends a request to a connected server on the LAN. The server processes the request and returns the result to the requesting node. For instance, to open a file, a node sends the request to a file server on the LAN. The file server searches the specified file and returns it to the node.

ADVANTAGES OF LAN

§  All the available peripherals and other expensive resources can be shared among the workstations.

§  Application software and data can also be shared among the workstations.

§  Users can communicate with each other through e-mail.

DISADVANTAGES OF LAN

§  A required resource may be unavailable if the server is down.

§  A LAN having few workstations may be expensive due to cost of additional hardware and software.

§  If not handled properly, data security may not be assured.

METROPOLITAN AREA NETWORK (MAN)

                        A Metropolitan Area Network (MAN) is a network that connects two or more local area networks together but does not extend beyond the boundaries of the immediate town/city. A MAN is typically owned and operated by a single entity such as a government body or large corporation. An example of MAN is a bank whose different branches in the city are connected using public telephone exchange and the systems are connected with each other using LANs within each branch and the different branches are connected using modems and bridges.

WIDE AREA NETWORK (WAN)

                        A WAN is a computer network that covers a broad area, often interconnects computers that are distributed all over the country or continent. A WAN is a geographically- dispersed collection of LANs. A network device called a router connects LANs to a WAN. In WAN, the transmission media used are normally public systems such as telephone lines, microwaves and satellite links. The largest and most well-known example of a WAN is the internet.

Some special hardware used in WAN are:

§  Bridges:  Bridge is an equipment that connects two similar networks.

§  Routers or Gateways: Router or gateway is a hardware that connects two dissimilar computer networks.

    There are generally two types of WAN, distinguished on the basis of accessibility. They are:

Ø Public Networks: These networks are controlled by the government. Public can use them by subscribing to the services. Some of the popular WANs are:

§  Integrated Services Digital Network (ISDN)

§  Public Switched Data Network (PSTN)

§  Value Added Network (VAN)

§  SWIFT

Ø Public Networks: These WANs are owned and controlled by a particular party and are not open for public use.

    The major difference between LAN and WAN is summarised in the following table.

Property	LAN	WAN
Geographical distribution	A LAN is restricted to a limited geographic coverage of a few kilometres. Therefore, LAN provides communication facilities within a building or a campus.	A WAN may extend over several thousand kilometres. Therefore, WAN may operate nationwide or even worldwide.
Data rate	Data transmission rates are usually much higher. Transmission rate ranges from 10 Mbps to 10 Gbps.	Transmission rate in WAN usually ranges from 1200bps to 6 Mbps. The data transmission rates are increasing continuously for both LANs and WANs with advancements in technology.
Error rate	LANs generally experience fewer data transmission errors than WANs do. Typical bit error rate in LAN falls with the 10(-8) to 10(-12) range.	Error rate in WANs is high and that falls with the 10(-5) to 10(-7) range.
Communication link	The most common communication links used in LANs are twisted pair, coaxial cable and fibre optics.	Typical communication links used in WANs are telephone lines, microwave links and satellite channels.
Ownership	A LAN is owned typically by a single organization.	A WAN is formed usually by interconnecting multiple LANs each of which may belong to different organizations.
Communication cost	The cost of transmitting data in LAN is negligible, since transmission medium is owned by the organization.	The cost may be very high because transmission medium used are leased lines or public communication systems.

WORLD WIDE WEB

                        The World Wide Web (abbreviated as The Web, WWW or W3) is a huge collection of interconnected websites. The WWW was introduced in 1989. Today the WWW includes billions of files stored on tens of thousands of computers (web servers) all over the world. These files represent text documents, pictures, video, sounds, animations, interactive environments or program files. These pages are interconnected via links called hyperlinks. By clicking at a hyperlink, we are presented with the page pointed by that link. This way we can go on browsing the web pages almost endlessly.

                        A website is a collection of all the related web pages. A number of websites may be stored on a web server. We can browse these pages using our web browser and the website’s URL. When we visit a website, the first page that opens up is called home page. We can browse the pages on the WWW using a browser. Microsoft Internet Explorer is an example of browser.

                                       PRASEETHA K. P.

ENGLISH.