We often see different pictures, songs and movies in our computer. Sometimes we also hear that some actions in films are not performed real but are made by computer animations. We see TV advertisements, different attractive advertisements in newspapers, and many other designs in walls, pamphlets and other places. How these have been possible after all? All of these things are made by using multimedia tools. These days, multimedia computers are used as the most prominent multimedia tool to develop such graphics designs, animations, videos, image editing, etc. multimedia computers are nothing but simply the computers like we use in our home which are enhanced with many other multimedia hardware and software. Multimedia computers are capable of generating, storing and displaying multimedia contents. Now a question arises”What is Multimedia?” lets try to answer it.
As the name implies, multimedia is the integration of multiple forms of media. Multimedia is the technology that uses any combination of different media; it may or may not involve computers. It may include several media like text, spoken audio, music, images, animation, and video. For example, a presentation involving audio and video clips would be considered a “multimedia presentation”. Educational software that involves animations, sound and test is called “multimedia software”. Multimedia programs are often interactive and include games, sales presentations, encyclopedias, and many more. Any systems can be said interactive if users could act or command the system and the system works accordingly. For example: in media player a playing video pauses if the user clicks on the pause button and starts again when user clicks on the play button and starts when user clicks on any button. The user’s clicks here are considered as the user’s interaction and the response made by the system is called interactive response. Users can interact in many other ways instead of mouse. If any multimedia supports or response specifically on one or more of the user’s interaction, then such multimedia is called the interactive multimedia. Such interactive multimedia has gained lots of popularity these days.
Multimedia requires the large amount of data to be stored. Hence, CD-ROMs and pen drives are the good option for storage of computer multimedia files. We could store multimedia in other high capacity storage devices which are also faster and easy to use. But mostly we choose CD-ROM and pen drive as multimedia storage devices as it is very cheap, it can store lots of data and it is very easy to store and handle. Such CD-ROMs which contain multimedia files are called “Multimedia CD-ROMs”. Nowadays we can get different multimedia CDs in the market which contain the entertaining and educational materials.
MULTIMEDIA SYSTEM
System means the combination of different components which work in coordination with each other in a certain manner so as to serve some specific purpose. Multimedia is the technology which can disseminate two or more different media like text, audio, video, etc in a single time frame. Thus multimedia system means the proper combination of different multimedia components which work together to create, edit, store and disseminate the multimedia components. Almost all of today’s multimedia systems take advantage of power and ease of computer systems. Without computers, today’s sophisticated multimedia cannot be thought of. So, multimedia system could be more accurately defined as the combination of computer hardware and software designed so as to create, store and disseminate the multimedia content.
The multimedia computer generally contains the following components.
1) Computer
2) Multimedia Software
3) Sound card
4) CD-Drive
5) Micro-Phone
6) CD-ROM Disk
7) Multimedia speakers/Head-Phones
8) Digital Camera and many other components.
All of some of the above mentioned components work together to make up the multimedia system which can capture, digitize, compress, decompress, retrieve the multimedia component (multimedia data) and show it into the output devices like Computer Monitor, Multimedia Projectors, etc. Literally speaking, all the components that could be used in the multimedia system are impossible to list out. The above mentioned are only some of the important components of multimedia computer system.
ADVANTAGES OF MULTIMEDIA
We have already mentioned various advantages of using multimedia. We can still specifically list out following points that explains the advantages of the multimedia.
1. It can be used to help students and teacher to teach as well as learn the given topics easily.
2. It can be used to spread the knowledge easily all over the world wide in the cheap cost.
3. It is easy to take the multimedia files from one to other places as it can be stored in the cheap and light storage devices like CD-ROM.
4. It can be used for any subject and for anyone.
5. It can be used in Television, Films Industries and for personal entertainments.
6. It is highly used to realize the concept of Open University, Distance Education System, and Video Conferencing.
7. It is also used in Internet to make up the interactive web-page contents.
8. We can give the everlasting impression to the intended audiences on a specific topic by the use of multimedia.
9. Colored pictures, Motion pictures and other graphics could be shown in monitors and other big screens so that many people could view it and make out the impression about it.
10. Multimedia systems are generally very interactive so it is interesting to use.
DISADVANTAGES OF MULTIMEDIA
In comparison to the enormous advantages we have very little disadvantages of multimedia. These disadvantages could be listed out as:
1. It is expensive to produce multimedia contents.
2. It is expensive to set up the multimedia systems.
3. It needs well trained manpower to create and use it.
4. Multimedia files are too large so, it is time consuming to transfer across the Internet and Intranet.
The computers on LAN can be physically connected with the wires in different manner as the requirement of an organization or office. The manner in which the computers on the LAN are connected is known as LAN Topology. So, network topology is the physical layout of cabling for connecting computers on the network. It can be defined as the arrangement or connection pattern of computers on a LAN. A LAN topology describes how the computers are physically connected and how do they communicate on the network. It determines the data paths that may be used between any pair of nodes of the network. There are three basic network topologies. They are Bus topology, Ring topology and Star topology.
BUS TOPOLOGY
In a bus topology computers are arranged in the linear format. So, it is called Linear Topology. In this topology, all nodes are connected directly to the common cable with the help of T-connectors. The common cable is also known as also known as a network bus or trunk. The network bus acts as a backbone to the network.Many different lengths of co-axial cables are used in this type of topology. On the both side of the network bus (i.e. coaxial cable), BNC (Bayonet Naur Connector) jacks are connected. A T-connector is used to join segments of cables and computers. The BNC jack on each side of network bus is connected to the T-connector i.e. top the T-connector is connected to the NIC card of a Computer. The T-connectors connected to the last computers on both sides are attached with terminators.
In this network topology, the position of the server is not fixed i.e. can be any where on the network. When any node sends the data, the data passes on both directions in the form of packets through the bus and reaches to all the nodes. Since each data packet contains the data bits and the destination address, only the destination node accepts the data packets. The terminators at both end sides absorb the packets or signals travelling on the bus to prevent the bouncing of the signals which causes interference.
ADVANTAGES
a. Since each small segments of cables are joined to form a trunk or network bus it is easy to setup computers on the bus.
b. Since nodes are arranged in the linear form, it requires the less amounts of cables.
c. The coaxial cables used for networking are inexpensive and joining connectors on the cables is also easy.
d. Failure of any node does not affect other nodes on the topology.
e. Well suited for temporary networks (quick set
up).
DISADVANTAGES
a. If the backbone cable i.e. network bus has problem then the entire network fails.
b. Finding fault on this topology is not easy.
c. It provides limited flexibility for change, so adding or removing nodes in between is not easy.
d. The performance degrades when the
number of computers is more on the. so, it is not suitable for big size network.
RING TOPOLOGY
In a ring topology, all nodes are arranged in the shape of a circle (ring). Both ends of a cable are connected to the nodes so there is no any point like a bus topology. Since the both ends are connected to the nodes there is no any terminator in this topology. In this topology, many different lengths of co-axial cables are used according to distance of computers. In this topology each computer acts like a repeater that boosts an incoming signal before passing it on to the next computer.
In this topology, data or messages are transmitted in one direction either clockwise or anticlockwise. When any node sends a message or data, the message or data reaches to the first node on the circle. If the first node in the circle is the destination node then it absorbs the data or message otherwise it regenerates the signal and passes to another node on the loop and so on. If the message or data is not absorbed by any node then it is absorbed by the sender node.
ADVANTAGES
a. Since each node on the ring acts as a repeater, no any external repeater is required to boost up the signals.
b. It supports high data transmission. Rate.
c. It is easy to setup.
DISADVANTAGES
a. If any node or connecting cable fails the entire network does not work.
b. The diagnosis of the fault is difficult.
c. Since data or message reaches on the node in sequence, so addition of few nodes increases the communication delays.
d. It provides limited flexibility for change,
so adding or removing nodes in between is not easy.
STAR TOPOLOGY
Star Topology is the most popular topology used to connect computers and other network devices on the network. In a star topology all nodes are connected through a centrally located device in the form of star. But the shape of arrangement of computers is not necessarily to be star. The device whic
h connects computers on the network is either a hub or a switch. A hub or a switch has connecting ports or slots where the wires running from each node are connected. A twisted pair cable (specially unshielded twisted pair cable) is used for connecting a computer and a hub or switch. Each segment of UTP cable is attached with RJ-45 jacks. And one side of the UTP cable is connected to the node and another side is connected to the hub or switch. When any node sends data or message, the data or message reaches to the hub or switch and then to the targeted computer on the network.
ADVANTAGES
a. Computers can be added or removed easily without affecting the network.
b. If any of the workstation or the connecting cable fails, it does not affect the remaining portion of the network.
c. Fault detection in the star topology is easy.
d. It is easy to extend so it is suitable for a large network.
e. It is one of the reliable network topology.
DISADVANTAGES
a. Since each node is required to connect with the centralized hub or switch more cables are needed which increases the cost of installation.
b. The entire network fails if there is any problem on the hub or switch.
c. In comparison to Linear and Ring topologies, it is little expensive as it requires more length of cables and other controlling devices.
.