The computer system is a combination of many parts such as peripheral devices, secondary memory, CPU, etc. This can be explained more clearly using a diagram.The salient points about the above figure displaying Computer System Organisation is −The I/O devices and the CPU both execute concurrently. Some of the processes are scheduled for the CPU and at the same time, some are undergoing input/output operations.There are multiple device controllers, each in charge of a particular device such as keyboard, mouse, printer etc.There is buffer available for each of the devices. The input and output data can be stored in these ... Read More

An operating system is a construct that allows the user application programs to interact with the system hardware. Operating system by itself does not provide any function but it provides an atmosphere in which different applications and programs can do useful work.The place of an operating system in a computer can be demonstrated aptly using the following diagram:As can be seen from the above diagram, the computer system is divided into four components namely, hardware, operating system, application programs and users.The operating system coordinates between the hardware and the application programs. It makes sure that adequate hardware resources are distributed ... Read More

Fiber optic cables are finding increasing usage due to a number of advantages over the traditional copper wires. However, there are a few flipsides in its usage too.Advantages of Fiber Optics Cables over Copper WiresFiber optic cables transmit data at much higher speed than copper wires. This is because the speed of light is greater than the speed of electrons.Fiber optic cables have a much larger bandwidth of over 60 Tbps in comparison to 10 Gbps bandwidth of copper wires.Fiber optic cables have very low attenuation. Repeaters need to be added only after every 50 km as compared to 5 ... Read More

Optical fiber cables are transparent, flexible fibers made up of glass or plastic through which light waves can pass. A bunch of fiber optic cables is shown in the following diagram −Structure of a Fiber – Optic CableA cross section of a fiber optic cable reveals three parts −Core −  It is the innermost portion of an optical fiber through which light propagates. It is cylindrical in shape and it made up of a flexible glass of high refractive index. The diameter of the core of a single mode fiber is 8 – 10 μm while multimode fibers are 50 ... Read More

In fiber optic communication, signals are transmitted through an optical fiber. This is based upon certain characteristics of light, namely refraction and total internal reflection.RefractionWhen a light ray goes from a denser transmission medium to a rarer one or vice versa, then its direction changes at the interface of the two medium. This phenomenon is called refraction of light.The density of an optical medium is measured in refractive index. Higher the refractive index, denser it is.The angle between the incident ray and the normal is called angle of incidence Θi, while the angle between the refracted ray and the normal ... Read More

In fiber optic communication, data is transmitted from the source to the destination by sending light pulses through optical fibers. It changes electrical pulses to light signals and vice versa for communication. Fiber optic communications are preferred when a huge amount of data needs to be transmitted across large distances.The process of communication using fiber optics has the following steps −Conversion of input electrical data to light signals : The data to be sent by the sender is in the form of electrical signals. These signals are converted to light pulses by the transmitter circuitry using a light source. A ... Read More

Coaxial cables, commonly called coax, are copper cables with metal shielding designed to provide immunity against noise and greater bandwidth. Coax can transmit signals over larger distances at a higher speed as compared to twisted pair cables.Structure of Coaxial CablesCoax has a central core of stiff copper conductor for transmitting signals.  This is covered by an insulating material. The insulator is encased by a closely woven braided metal outer conductor that acts as a shield against noise. The outer conductor is again enclosed by a plastic insulating cover. The structure is shown in the following figure −Categories of Coaxial CablesCoaxial ... Read More

The primary purpose of computer networks is to transfer data from a source machine to a destination machine. One of the elementary ways to transfer data between machines is to use removable storage media. The steps for the transfer are −Copy data from the source computer to the removable storage device.Physically transport the removable device to the source computer.Copy data from the removable device to the destination computer.Some of the removable media that can use for transferring data between devices are −Magnetic tapesOptical discs like CDs, DVDs, and Blu-ray DiscsUSB flash drivesZip discs and floppy discsMemory cards and Memory sticksAdvantages ... Read More

The transmission medium can be defined as a pathway that can transmit information from a sender to a receiver. Transmission media are located below the physical layer and are controlled by the physical layer. Transmission media are also called communication channels.Transmission media are of two types −Guided Transmission MediumUnguided Transmission MediumThe following chart categorizes transmission media −Guided Transmission MediumGuided transmission media are also called bounded media or wired media. They comprise cables or wires through which data is transmitted. They are called guided since they provide a physical conduit from the sender device to the receiver device. The signal traveling ... Read More

Bandwidth The range of frequencies that are used for transmitting a signal without being substantially attenuated is called the bandwidth. It is calculated as the difference between the highest and the lowest frequencies. It is expressed in Hertz (Hz).For example, if the minimum frequency is 100 Hz and the maximum frequency is 1000 Hz, the bandwidth will be 900 Hz.The bandwidth of a transmission medium is the frequency width of the medium and is dependent upon its physical characteristics like thickness, material, length etc. For example, the bandwidth of a coaxial cable is 750 MHz ( MegaHertz).BasebandBaseband transmissions are those requiring ... Read More