Computer Fundamentals

Before you learn about Fundamentals you need to have simple concept about hardwares like Computer, Printer, Network Interface Card , Router. No problem if you have never heard I shall help you well I shall be helping you with all these relations.
Ok now this definition is damn sure in SLC

NETWORKING

"Q: What is a computer Network??"
"A: A network is a group of two or more computers interconnected by cable or other some media enabling them to share informations and resources"

In detail about computer network
Well if you have visited offices or cyber cafe's you might have seen the receptionist sending mail to another user or personnel in same office to visit him/her via computer. Well how is it possible to send emails files or information from one computer from another?? the simplest answer is "it is possible due to computer network" they send emails , databases and files the computers are connected by cable or other media's now in this chapter we gonna learn advantages and disadvantages of networking , it's types , components , types of topology , media , bandwidth ,cables, types of transmission, protocols, network hardware,etc.


Now please dont be stuunned by these stunning words i have defined these in next page "Terms"

Now let us get started with advantages and dis advantages please be sure that this question is almost sure in your SLC you will need to learn entire

TIPS::You need not ROT these if you understand well if you understand well you can just review this page once at your exam times and be sure that you will score great

ADVANTAGES:
Networking has a number of advantages like sharing files and resources, sending electronic mails between users, database sharing, easy to set up new equipment, reliable medium of communication etc. However in your exams you might not need in points although I've listed them below in points

=>1:.It allows sharing of information's which is on disk and drives to all users who are authorised
=>2:.It allows sending of e mails between users which can increase efficiency
=>3:.It allows multiple users to share hardwares and resoueces like printers, storage devices, image scanners, modems and several other devices

NOTE:you will not need to write more than three points for one marks

DISADVANTAGES
Computer Networking is a great mess and it needs skillful personnel's to set up a network it is expensive too and not useful to those users who use computer in a less platform (ie in less number)

=>1:.Users become dependent if main server fails every one will be in trouble utilizing hardware and resources
=>2:.When computers are in network mode it will be easier for hackers and novices to steal useful and confidential data's
=>3:.The speed of Network decreases as per the increase in the users or nodes (ie traffic)

Well i guess you have understood and till now have a good concept of Advantages and Disadvantages of Networking. Now you can workout with Types of Network

TYPES OF NETWORK
It's not that evolution was done at once there were diffrent levels . Now we are gonna learn about various levels of evolutions of Network (ie types of network)

There are different types of network we use like Public network, Home network, Metropolitan network, Local area network etc.
List's of types of network's are
=>1:.LAN (Local Area Network)
=>2:.MAN (Metropolitan Area Network)
=>3:.Other Networks like Internet

Details about Each type of Network

1)PRIMARY TYPE

Local Area Network (LAN)
This type of network is limited within short geographical area's like a building, an office a room etc. This type of network is used to connect small places For example :Offices, Buildings etc.

Metropolitan Area Network (MAN)

A Metropolitan Area Network is limited to only metro policies. It is basically a network created to link government offices in a a metropolitan city or etc MAN can be further connected to Internet. This type of network can support data voice and images transfer . For example A metropolitan Network of Traffic Police, Network of Government Offices etc.

Wide Area Network (Wan)

Wide Area Network's cover large geographical area's with many owners according to statistics most of the WAN owner's are ISP(Internet Service Provider)


2)Secondary Type

Client-Server Network

It is clear by the keyword Client Server that this type of network is controlled by a powerful server. Any Activity cannot be performed by client unless server allows. The work station works only for the person sitting on the node but the server serves all nodes connected to it.

NOTE: A server is the fastest and powerful computer to run various software, store and process information and to provide a Human Interface for the user to be able to use the network computers

Peer to Peer Network

Peer to Peer Network is the type of network in which each and every computers are connected to each other. All nodes have equal right to re transmit what ever they receive this is an active mode of network. In this network each computer pass token to each other

Differences Between Server Based networks and Peer to Peer networks

Server Based

=>1:.A central backing store is avilable to all users
=>2:.Software is centrally held and shared
=>3:.User id's passwords and access levels are controlled by the central computer
example : Novell's net-ware Linux etc

Peer to Peer based (p2p)

=>1:.Peer to Peer based network has a system of token and all nodes have equal authority
=>2:.All Computers connected are independent
=>3:.Security is not centrally controlled

COMPONENTS of a COMPUTER NETWORK

Server : Server is fast and powerful Computer to run various Software, Store and process information and to provide a human interface for the user to be able to use the network computers

Nodes : Nodes are the computers on the Network which are provided to the users to carry out their tasks

Another broad term in networking is Network Cables : This is the medium over which the information travels from computer to computer

Network Interface Card : Network Interface card also known as NIC is the primary hardware useed to connect computer's hardware and network's physical medium (ie cables)

Networking Operating System : Network Operating System Commonly known as NOS is considered as a main component of network it is because no networks can operate without NOS examples of NOS are Windows98, Windows sp2, Novell's Net-ware etc.

TYPES OF TOPOLOGY

A network topology refers to the physical layout of the network in which all the devices are connected . This includes all the hardware that makes up the network all the devices are connected. This includes all the hardware that makes up the network by the station are called nodes or work stations. There are several types of topographical design and strategies used to implement LAN. The majority of these are based on three types of topologies

=>1:.Star
=>2:.Bus
=>3:.Ring

Star Topology :This is a topology where all the computers are connected to a central connecting device , Hub. Data on this topology passes through the hub before getting to it's destination.
NOTE : HUB is a central connecting devicewhich connects all computers

Advantages: The basic advantages of this type of topology is listed below
=>1:.Easy to install and setup
=>2:.no disturbing when nodes are added and removed
=>3:.Easy to detect faults and remove them

Disadvantages:
=>1:.requires more cable length than a bus topology
=>2:.If the central connecting device hub fails , nodes attached are disabled
=>3:.More expensive than bus topologies because the cost of the concentrators

Bus Topology : Bus Topology is the simplest type of topology that can be used in the network. it is reliable in a small network and easy to use. It has a single cable acting as a backbone called a trunk . Fromk the trunk via BNC T(Buyo Nut T Connector). In this tyope of topology coaxial cable is used mostly.

Advantages:
=>1:.Easy to connect a computer or pheripheral to a linear bus
=>2:.Requires less cable length
=>3:.This type of network is fast in small offices buildings or rooms

Disadvantages:
=>1:.It is difficult to detect problems and entire network doesn't works when trunk has defects
=>2:.Terminators are necessary a both the ends of trunk to avoid signal loss
=>3:.Difficult to identify defects and remove them

Ring Topology : This is a type of network architecture in which all computers are connected to each other ie the first one is connected to second and last in the form of ring. This is an active mode of network since eery nodes get equal right to re transmit everything they recieve

Advantages:
=>1:.Very orderly and active network
=>2:.Performs better than a star topology
=>3:.Can create much larger network using token Ring

Disadvantages:
=>1:.Entire Network Shuts down even if a single port creates problem
=>2:.Moves, adds and change in network may create a lot of mess and problems
=>3:.Much slower than ethernet network under normal load

Bits and Bandwith

Note: The Concept of bits and Bandwiths are not so much important but they may twist our mind specially on short questions. Hence i recommend you to learn these.

Bandwidth

:number of bits that can transfer over a given medium in a given tome is known as bandwidth.

Multimedia

The Concept
Multimedia is the field concerned with the computer-controlled integration of text,graphics(pictures), drawings, still and moving images (Videos),animations,audio, and any type of media where every type of information can be represented, stored, transmitted and processeddigitally. Or it can be defined as the processing and prasentation of information on acomputer in a more strucured and understandable manure using more than one media. Thus multimedia products can be educational presentation, game or business presentation, information kiosk, fashion designing etc. Multimedia systems are those computer platforms software tools that support the interactive uses of text, graphics,animation,audio or motion video. In other words, a computer system capable of handling different media's is called multimedia computer. If the sequence and timing of these media elements can be controlled by the user, then one con name it as Interactive Multimedia.

Fig 1.1 Info

Fig Multimedia Requirements

A typical multimedia computer usually includes devices like CD-ROM Player, Sound Card such as Sound Blaster, Master Blaster and somtimes a Microphone and a rnge of muiltimedia software.

One cannot record a video using such a system. For doing recording one reuires additionl equipment such as video camera. However, once various components of multimedia are recorded in the required format, this machine can be used to put various pieces together to form a muliimedia information system. Many multimedia machines, however, are equipped to record a sound. Let us explore more about the hardware related to the multimedia technology. 

The uses of the basic components of multimedia areas follows:

=>1. The text can be used for adding emphasis. 

=>2. Graphics provides a visual impact.It is generally said that a picture is worth or thousand words. Thus, graphics can be used for enhancing s presentation.

=>3. The voice tries to enhance presentation to the extent that it moves on to the from of persuasion. many people want to listen about a particular topic rather than reading a about it.

=>4. The animation can be used effectively for attracting attention.

=>5. Animation also make a presentation light, thus, it can be used for the presentation of several complex subjects. It is also a tool that helps in focussing attention; for example, a chart if drawn through animation can be understood faster.

=>6. The video part of a multimedia can be used as a powerful communicator providing clear-cut insruction.

COMPUTER VIRUS

Computer Virus were named Virus because they create malfunctioning's  on your computer when they get into your computer system.

Q: What is a computer Virus?
A: Computer Virus is a parasitic program written intentionally to enter a computer without the user's permission or knowledge to do something you never want

Computer Virus is a parasitic program written intentionally to enter a computer without the user's permission or knowledge to do something you never want. Basically a computer virus is a special kind of computer program, which spreads across disks and networks by making copies of itself , usually secretly and can produce undesired side effects in computer system

TYPES OF COMPUTER VIRUS

=>1:.Message carrying Virus
=>2:.Boot Sector Virus
=>3:.System Infectors
=>4:.Application Infectors or program Viruses

=>1:.Message carrying Virus
These Virus do not infect the computer programme's and do not damage data and information but display pop ups, interesting messages, sometimes even advertisements, dialogues etc which may disturb the user

=>2:.Boot Sector Virus: These Viruses infect diskettes and hard drives and become active when a infected disk is used to boot  a computer. These viruses infect Boot Record, Master Boot , FAT and Partition Table.

=>3:.System Infectors: System Infectors infect destroy corrupt system file they usually stay in system files like system32.exe, MSDOS.exe etc. These Viruses are fatal Because they Destroy System files

=>4:.Application Infectors or multipartite virus:   These Virus infect computerprogrammes executable files  (.exe,.cmd,.sys,.bin etc) and become active when the infected program runs.These virus show multiple Feature which can infect both programs and boot sectors.

There Are two types of application infectors they are
=>1:.Multipartite Virus: These virus show multiple Feature which can infect both programs and boot sectors.
=>2:.Document Virus or macro virus: These Virus infect Ms Word documents through macro programming capabilities. Macro Virus Becones active when infected Document is opened

How Do Computer Virus  Spread ?
It is strange you don't put virus although you get surprised wen you see your computer infected with Virus. Here are some wise From where Virus can spread

=>1:.Booting a computer from a infected medium
=>2:.Executing an infected program
=>3:.Opening an infected

Common Routes For Computer Virus Infection

=>1:.Floppy disks or other media that users can exchange
=>2:.E mail attachments
=>3:.Pirated Software
=>4:.Shareware

Common Symptons of infection

=>1:.Your Program takes long time to respond and open
=>2:.The light of your disk keeps on flashing even when you don't use
=>3:.Your Computer may not remember CMOS (Complementary Metalic Oxide Semiconductor) even if the Battery is new


Preventive Measures


=>1:.Use Antivirus softwares like AVG FREE, AVAST MACAFEE NOD32 etc. And update Antivirus databases frequently
=>2:.Buy Original Softwares and don't use freewares and sharewares
=>3:.Avoid Infected disk drives into your system

Cure
The Virus are omnipotent (stoppable). They can be cured with antiviral programmes. The Antiviral programmes can perform one or more of following functions:
=>1:.Prevention
=>2:.Detection
=>3:.Vaccination
=>4:.Immunization
=>5:.Identification, and /or
=>6:.Damage control
Some antiviral programmes are : Mcafee Scan, CPAV,  MSAV, TOOLKIT,NAV etc.

Antivirus: A program or software that detects and removes the computer virus from an infected file, program all memory addresses is an antivirus program or software.