describe the ring topology?discuss the Advantage and disadvantage .

describe the ring topology?discuss the Advantage and disadvantage .

Ring Topology                           In a ring topology, each computer is connected to the next computer and the last computer is connect... 21:03

Ring Topology
                          In a ring topology, each computer is connected to the next computer and the last computer is connected to the first. thus, shape of network is formed just like a ring. Data on the network flows in one direction around the ring until it reaches to destination.

Working of Ring Topology
                   In ring topology, a token is passed around the network. the computer that has control of the token can transmit data/message. When  computer sends a message to another computer on the network, the message flows one computer to the next computer. Every computer receives message from  previous computer and re-transmits it to the next computer until the destination computer receives the message. the

destination computer sends an acknowledgement of receiving  message to the sender computer. the sender computer then releases the token back to the network. this method of controlling access to the shared network cable is called Token Passing.

Advantages
the main advantages of ring topology are as follows:
1-    it is less expensive then star topology.
2-     it is easy to install and to maintain.
3-    All computers have equal access to the network.
4-    Every computer regenerates/refreshes the data single that's why it can travel over longer distance.

Disadvantages
the main disadvantages of ring topology are as follows:
1-   if one node fails (or ring is broken at any point), the entire network stops functioning.
2-   Adding or removing a computer in the network affects the whole network.  

what is computer networks?what are server computer and terminals or nodes used in computer network?

what is computer networks?what are server computer and terminals or nodes used in computer network?

Computer network A collection of computers and other devices that are linked together by communication channels or lines for sharing informa... 22:28

Computer network
A collection of computers and other devices that are linked together by communication channels or lines for sharing information and other resources is called computer networks. The resources may include printers, scanners, and hard disks etc. computer networks is also called the information network are simply net. The most popular information network is the internet.

   Ina computer network, two important technologies:computing and telecommunication work together.The computers on a network may be linked through cables,telephone lines, radio waves (wireless), and satellites etc. Figure 2.1 shows the computer network.

      In a computer network, network operating system is used that cables the connected computes to communicate with each other. the example of these operating system are: Windows NT, UNIX, and Novell etc.

Server Computer & Terminals

      A computer and the network that controls the overall functioning of a network is called server computer. it is also known as central computer. in addition to control the network, all data files and software are stored on server computer. A powerful computer is installed as server computer in the network.

                  The devices other than server computer within the network are called terminals. Terminals are also known as nodes. A node may be personal computer, printer,scanner, monitor etc. The users in the computer network access data and other resources through terminal computers.

what is a secondary storage device?list different type of secondary storage devices used in computers.

what is a secondary storage device?list different type of secondary storage devices used in computers.

Secondary Storage Device the main memory or RAM of the computer is volatile. It cannot be used permanent storage because when computer is sw... 21:31

Secondary Storage Device
the main memory or RAM of the computer is volatile. It cannot be used permanent storage because when computer is switched off, its contents are erased. storage capacity is also very small.

A secondary storage device is a computer hardware component. it is used to storage data and programs permanently for later use. secondary storage devices are also called auxiliary storage devices or backing storage devices. Examples of secondary storage devices are floppy disk, USB driver, hard disk, CD/DVD ROMs etc.

A secondary storage device performs two functions. these are writing and reading data to and from the storage media.
1-  Writing data means recording data form memory  to a storage medium.
2-   Reading or retrieving data means transferring data form storage medium in to computer's memory       for use by the operating system or application program.

Types Of Secondary Storage Devices
Following are important types of secondary storage devices:
1- Magnetic tape
2- Magnetic disk

Magnetic tape
Magnetic tape is the most popular and oldest storage medium.it is used to store large amount of data and instructions permanently. the magnetic tape is a plastic ribbon with width of 0.50 inch to 1 inch. one side of tape is coated with magnetic recording material. the storage capacity of tape is up to 100GB and offers an inexpensive way to store a lot of data on a single cassette.
Magnetic Disk
Magnetic disk is a device that write/reads data to and form a magnetic tape. it has two heads. these are write head and read head. the write head encodes the magnetic signals on the tape as it moves across the write head. similarly, the read head reads the stored data from tape and transfers it into the RAM.