Communication and Network

Twisted pair :
A cable composed of two small insulated conductors twisted together without a common covering.


Coaxial cable :
Consists of an outer conductor and an inner conductor separated by an insulating plastic filler. Usually,these two conductors usually carry equal currents in opposite directions,some of the examples are cable TV hookups and also certain types of computer networks.

Fiber-optic cable :

A technology that uses glass or plastic, threads (fibers) to transmit the data.A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages to modulate onto light waves.


Node :
In a communications system, a node is a network junction or connection point. Every terminal, computer, hub and switch is a node.But,in database management, a node is an item of data that can be accessed by two or more routes.


Client :

The customer of a vendor or consultant. The client of an IT department is the end user.At the same time,it also refer like a user's computer, which is generally a Windows, Mac or Linux desktop or laptop. The term implies that the client machine is connected to a network

Server :

A server is an application running on a computer that delivers a service and the way a server and a client dialogs is called a protocol

Hub :
It is important place because its facilitating movement or transportation whilst supporting a load, or performing labor in machines

Network Interface Card (NIC) :

In computer networking, it provides the hardware interface between a computer and a network.

Network Operating System (NOS) :

An operating system that contains components and programs that allow a computer on a network to serve requests from other computer for data and provide access to other resources such as printer and file systems

Host computer :
The host computer is used to run the debugger.

Network manager:
Refers to the broad subject of managing computer networks.Some of the examples are...

Performance: Eliminating bottlenecks in the network.

Reliability: Making sure the network is available to users and responding to hardware and software malfunctions.

Second Storage

Disk caching :

A temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data.

Redundant arrays of inexpensive disks (RAID) :

Organization of multiple disks into a large, high performance logical disk.

Disk arrays stripe data across multiple disks and access them in parallel to achieve:-
(i) Higher data transfer rates on large data accesses

(ii) Higher I/O rates on small data accesses.

Data striping also results in uniform load balancing across all of the disks, eliminating hot spots that otherwise saturate a small number of disks, while the majority of disks sit in is original.

File compression and decompression :

Image compression is minimizing the size in bytes of a graphics file without degrading the quality of the image to an unaccceptable level. The reduction infile size allows more images to be stored in a given amount of disk or memoryspace

Input and Output

Magnetic Ink Character Recognition(MICR) :

A tool that commonly used in banking area,the technology itself allows the computers to read information (such as account numbers) off of printed documents.

Optical-Character Recognition(OCR) :

The mechanical or electronic device translation of images handwritten, typewritten or printed text into machine-editable text.

Optical-Mark Recognition(OMR) :

It is defined as a scanner device that shines a beam of light onto the form paper. This is because the contrasting positions on the page is utilized to detect the marked are due to reflection of less light than the blank areas of the paper.

Dot-matrix printer :

A computer type printer with a print head that runs in four side(back,front,up and down) on the page with the help of inks .Besides that,the dots,is produced by a tiny rod called a "wire" or "pin", which is driven forward by the power of tiny electromagnet.

Plotter :

Plotters differ from printers in that they draw lines using a pen. As a result, they can produce continuous lines, whereas printers can only simulate lines by printing a closely spaced series of dots.

Photo printer

Commonly it used to print out a high quality photos on a photo paper.

Portable printer :

It is wireless printer that can straightly print out the picture from the digital camera.

Fax machine :

The design just like a normal house telephone but slightly different in sense that this device can transfer a copy of documents including the picture too but using a certain number or code to transfer it.

Multifuntional device :

Multifunctional devices bring the worlds of copying, printing, finishing, and scanning together, all in one neat, using one device without costing you a lot of money.

Internet telephones :

An instrument that converts voice and other sound signals into a form that can be transmitted to remote locations and that receives and reconverts waves into sound signals.Example Skype,Yahoo Messenger and Windows Live Messenger.