Information Technology or IT is an important component in the teaching and learning process. To excel in this role, you as a teacher have to understand a number of basic concepts in the management of IT in operating and maintaining the computer as well as the computer laboratory. This topic will discuss three important aspects in this management: the maintenance of the computer, its basic networking and managing the computer laboratory. Managing IT is useful too in managing the resources of IT in teaching and learning.
SOFTWARE MAINTENANCE
Computers are dynamic machines and constantly support changes and addition of software. A computer usually possesses the minimum software which consists of the system software, utility or various other software.
With this variety of software available in the computer, proper maintenance has to be carried out to optimise the ability of the computer.
6.1.1 Scandisk and Defrag
Sca n di s k is a utility that function to:
(a) Scan and repair physical and logical problems found in the hardisk and diskette. Physical problems cover scratches on the hardisk or diskette surface. Logical problems on the other hand, refer to problems relating to data for example on the F i le All o cati on T a b l e .
(b) Search and Remove unwanted files.
Disk Defragmenter (i) Allows the data to be accessed faster (ii) The program operates faster
When the computer saves the data on the hardisk or diskette, the data is placed on the first sector of disk that can be used. The computer will try to place the data consecutively (close). However, this does not always occur. When the contents of a file are spread between two or more sectors, it is said to be fragmented. This causes slow access and subsequently affects the computerÊs performance. This problem can be solved by using the Disk Defragmenter utility facility.
You can use various methods similar to the ScanDisk operation to open Defragmenter facility.
(i) Click the button Start > Programs > Accessories > System Tools then click on Disk Defragmenter. The Defragmenter process will be carried out in two modes: (a) Setting Mode – utilities can be carried out in the background without being displayed to the user. (b) Visible Mode – the screen will display the defragmenter process
Erasing and Deleting Files
Files created can be erased and deleted to avoid overloading of unwanted files that can reduce the storage space in the hard disk. Deleting files can also rearrange file arrangement on the computer.
Windows has an operation that provides the facility to erase and delete files.
(a) Bring the cursor and activate the file that has to be deleted.
Installation of Software You can add other software into your computer. Windows system operation provides the facility to install software.
There are many methods to install a software. Some software has the auto-install feature and you can install the software directly. In order to install manually, the following steps can be taken: (i) Click on the icon MyComputer on the desktop. (ii) Click CD-Drive on the MyComputer . (iii) Click file.exe to start the installation.
BASICS OF NETWORKING
To share resources or hardware
With a computer network, the user can share resources and hardware such as file, printer, modem, fax machine. To share software The user does not have to have a system to download all programmes or software into their computers. They only need the basic software to run the computer. For the other software, the user can share or get it directly from other users or from the server. To increase productivity By using the computer network, users find it easier to share data and information among themselves. Cost Effective When users share resources, hardware and software, users find it easier and financially it is more cost effective. Faster Users do not have to waste time exchanging information with other users. All that is needed is a computer that is linked to another computer.
Computer
Network Components and Topologies
Components in a Computer Network
A computer network comprises all computers, peripheral, interface card and other devices to carry out the processing of data and communication within a network.
There are seven components that are needed as a network device:
File Server
A file server is the core component of most networks. It is usually a high-powered computer in terms of RAM and storage space including interface cards. The network operating system is embedded in the computer along with application software and shareable data files.
Workstation
All computers that are connected to the file server are known as work station. A typical work station is a computer which is equipped with a Network Interface Card, network software and some cables.
Network Interface Card (NIC)
The Network Interface Card (NIC) has a physical connection between networks and workstation computers. Most NICs are internal with a card that is added to the slot in the computer. A number of computers like Mac Classics use the external box that is attached to the serial port or port SCSI
Concentrators/Hub
Concentrator is a device that connects the central point of the cable of the work station, file server and peripheral.
Repeater
Whenever a signal moves in a network, it reduces in strength. A repeater is a device that identifies signals when the signals cross it. It does this through electrical sparks on the signals received and confirms it again. The repeater
Bridges
A bridge or connector functions to allow a big network to be divided into two smaller networks. This improves the quality of service of the network. A bridge will facilitate an old cable system to be connected to the latest system network.
Router
A Router functions as a translator of information from one network to another network.
Network Topologies
Network topology refers to how the computers are connected through mapping.
Network topology is divided into two types that is the physical and the logical topology. • The physical topology for a network refers to the configuration found on the cable, computer and other peripherals.
Below are among the types of main topology.
(i) Bus or Linear Bus
The Linear Bus Topology contains a cable which is the main body and the life of the computers in the network. It is normally found in an environment using coaxial wires. These cables have a starting point and a terminator that is fixed at the start and end of the cable. Between these two points are the personal compuer and the computer server networking between one another. All nodes (server files, workstations and peripherals) are connected to the said linear cable.
Advantages of the Bus Linear
– Can easily connect a computer or peripheral to a Linear Bus topology.
– Easy, cheap and easy to use.
Disadvantages of the Bus Linear
– Any problem encountered in any of the nodes in the network can jeopardise the function of the whole network.
– The starting and terminating point or stop is needed for both ends of the cable backbone.
Star Topology or Spider
The Hub will first process the message and then send it directly to the personal computer and the destination node. This topology is also quite safe and easy to use. As its function is based on the use of the hub, any malfunction of the nodes or the personal computer will not affect the whole network. However, if the hub itself malfunctions, then the whole network is affected.
The Advantages of the Star Topology
– Easy to install and to fix the wiring.
– The network will not be affected if one of the devices or peripherals is connected or moved.
– Errors and malfunctions are easily detected and spoilt hardware can be transferred.
The Disadvantages of the Star Topology
– It needs a greater quantity of cable as compared to the bus topology.
– If the hub or concentrator fails to function, the node will also fail to function.
– It is more costly than the Bus Topology as the cost of the concentrators is high.
– When the host computer is not functioning, all computers will be affected and a large amount of computerisation power will be lost.
Token Ring Topology or Star-Wired Ring
This topology is not as popular as the bus topology or the star topology. The shape of this topology is round. This is because each node and personal compute is connected to the following node and personal computer.
Hence, in this topology, each node and personal computer is reliant on each other. If one of the computers malfunctions, the whole network cannot function.
Advantages of the Token Ring Topology
– If communicaton between the two corresponding systems breaks, an alternative route between these two places can be used.
– Easily installed and wired.
– It is easy to identify errors and defects and easy to separate the specific hardware
Disadvantages of the Token Ring Topology
– Requires a longer cable like the star topology.
– If the Hub or concentrator fails to function, the node too fails to function.
Network Protocol
Network protocol is a standard measurement that allows the computer and the IT device to communicate between one another. It is used to control communication in the network.
The role of the protocol on computers that send data is as follows:
• Data is divided in smaller sections called packets.
• Add the address information on the packet so that it reaches its destination.
• Preparing the packet to be sent through the network card and through cables.
The role of the computers that receive data are as follows:
• Taking the packet from the cable passage and straight to the network card.
• Collecting all the packets to the buffer that is sent to assemble again.
• The data that is assembled is used/ changed by the application/ programmed to a form that can be used.
Communication Protocol : Ethernet
• First established by Xerox Corporation in the late 70Ês.
• Ethernet uses the protocol CSMA/CD (Carrier Sense Multiple Access/Collision Detection).
• Carrier Sense – connector/ data transmitter
• Multiple Access – a computer in the free network to send data as long as other computers are not there in the said network.
• Collision Detection – When two computers send data simultaneously, there will be a clash, then the data from both computers will be sent again in a short span of time.
• CSMA/CD – The Protocol which allows computers to communicate simultaneously and provide ways to solve the problem in the event of a clash of data
Communication Protocol: TCP/IP
• TCP/IP is actually two protocols, but as they are always used together, so they are accepted as a sole system. • The Data that is sent is broken into smaller parts (packet) and then is attached with the senderÊs address and the recipientÊs address. • As data is sent as a packet, there is a chance that the data sent to the recipient does not arrive in sequence. • TCP – functions to ensure that each packet reaches the destination in good order and each packet is numbered well. This is so that the receiver arranges the data according to the correct sequence. • IP – is responsible for providing the address for a computer or device.
Information Sharing
Local Area Network (LAN) The LAN Network is usually limited to a small georgraphical area such as a building, school, office or campus. The basic function of LAN as a network is to connect a number of computers in a restricted area such as the university compus, in a smal building, in a room and often connected to a main computer framework or minicomputer. However, very rarely does the LAN network covers an area of more than 1 mile distance. These computers can be connected by various methods such as twisted pair cable, fibre optic, telephone lines, infrared lights and radio signals.
Metropolitan Area Network (MAN) Metropolitan Area Network or MAN usually covers a geographical area quite vast compared to the network covered by LAN. The MAN network usually operates in cities, a group of schools or in a small district. With a comparatively wide communication network in a geographical vicinity, information can be disseminated widely, quickly and effectively.
Wide Area Network (WAN) It covers a wider range between towns or between states and using the microwaves, telephone cabes, satellites or other means of communication. They could consist of a number of LAN or connected by a number of LAN.
LABORATORY MAINTENANCE
Safety and Laboratory Regulations
(a) Laboratory Regulations The Learning of IT is conducted in the computer laboratories. As the computer laboratories are equipped with electronic equipment, users must follow the regulations regarding the safety of computer equipment.
Below is an example of the Computer Laboratory Regulations. Read and add on any other regulations which you feel are necessary in a computer laboratory.
(i) Regulations on the Use of the Laboratory
• Students can only enter in the presence of a IT lecturer. • All bags are to be left outside the laboratory. • Food and drinks are not allowed into the computer laboratory
• Disconnecting any connection of the computer system will damage or render the computer faulty. • Any equipment or software is not allowed to be removed from the laboratory without the lecturerÊs permission. • The Computer system is only for learning and teaching purposes. • You should get permission from the lecturer to access the Internet • Report any malfunction or foul odour to the lecturer. • Carry out any other relevant regulations.
(ii) User Safety • Ensure the computer tables are arranged, the unit system is placed in the suitable place and devices have enough space. • Ensure your seat is comfortable and you sit up straight to prevent any backache. • Use a glass filter for your monitor for your comfort and safety. • Align your monitor at eye level, the distance from the monitor to the eye has to be 18 inches to 24 inches. • Do not open the casing system unit, as you might get electrocuted. • Switch off the computer, the electric supply and remove the plug from the socket when maintenance work is to be carried out on the system unit.
(iii) Ensuring Data Safety The file that is saved in the hard drive has to be copied into the diskette or into another secondary storage. This is to ensure that there is a copy of the original file in the event the file is corrupted by virus.
• The diskette that has a copy has to be write-protected.
Protecting the Computer from Virus
- There are many kinds of software that assist man to run computers efficiently and easily in their daily task. These software are available in various forms. At one time, the software was in the form of a diskette. However, with the advancement in CD technology, most softwares are in the CD form.
- A Computer Virus is a computer programme. A computer virus doesn not evolve on its own but is written or created by a person with an intention. The computer virus can spread and affected other programmes on the system. It is usually hidden.
- A VIRUS is a program, a script or macro that is more dangerous because it can explode, spread or even multiply. Virus can be written by experts in computer programming. It aims at sabotage, investigation, research, comedy or business.
The Virus can enter the computer system by two ways that is:
• Through a copied programme or file from a disk • Through the virus replica process itself
- Example of Viruses • Creeper – the first virus to be invented in the year 1970
• Christmas Virus – invented on Mar 1990. It displays the christmas tree on 24 December until 1 January every year.
• Brain – existed since 1986. It spoils the boot sector and FAT and changes the disk label.
• Dark Avenger - from Bulgaria in the year 1989. It attacks the file.com , .exe and .ovl
• Den Zuk was detected in Indonesia on 1988.
• Ping Pong – was invented on Mac 1988. The display screen shows the picture of a bouncing ball.
• Stoned – created in February 1988.
• Michael Angelo – exploded on March 1992
Signs of Virus Attack
• A program takes a longer time than usual to run.
• Disk operations seem difficult to conduct.
ERROR message are displayed.
• Free Memory in RAM reduces.
• Programs or files disappear strangely.
• Changes in file size especially exe. and com. files.
• There are hidden files.
• It attacks the File Allocation Table boot sector or FAT that is spoilt and will cause the file in the disk to be undetected and the boot sector that is spoilt will not be able to start the computer system.
• It attacks the file by changing the code and contents of the file disabling its use. • It lags the computer and finally the system breaks down when it spreads and fills the computer memory.
• It changes the disk label.
• It creates a bad sector causing loss or inaccessibility of data.
• It shows an untrue display screen.
(c) Ways of addressing the Virus
(i) Preventive Methods
• Use a password so that only specific people can use the computer.
• Always scan for virus using anti-virus scans such as MacFee Scan, PcCillin, TAVS and others..
• Always close the write-protect tab on the diskette.
• DonÊt save data in the hard drive as it is difficult to write protect the data.
• Always prepare a backup so that there is a copy in case the original disk is spoilt.
• DonÊt share diskettes. There may possibly have virus in it. (ii) Defense Mechanism • Insert the anti-virus software TSR (in the memory such as ARMOUR, DR SOLOMON and others. In this way, the virus can be detected automatically every time the diskette is accessed.
• Restoration Methods
- Laboratory Use Time Table A Time Table for the use of the Laboratory has to be arranged well so that the teaching and learning process can be implemented well.
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