Communication and Network

Modulation

Modulation is the addition of information (or the signal) to an electronic or optical signalcarrier. Modulation can be applied to direct current (mainly by turning it on and off), to alternating current, and to optical signals.


Demodulation

The conversion of a modulated carrier wave into a current equivalent to the original signal.


Bandwidth

Bandwidth refers to how much data you can send through a network or modem connection. It is usually measured in bits per second, or "bps."


TCP/IP

Short for Transmission Control Protocol/Internet Protocol, the suite of communications protocols used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP. 


Node

 In a communications system, a node is a network junction or connection point. Every terminal, computer, hub and switch is a node.



Client

An architecture in which the user's PC (the client) is the requesting machine and the server is the supplying machine, both of which are connected via a local area network (LAN) or a wide area network (WAN) such as the Internet.


Server

As the name implies, a server serves information to computers that connect to it. When users connect to a server, they can access programs, files, and other information from the server.

Network Operating

An operating system that is designed for network use. Normally, it is a complete operating system with file, task and job management; however, with some earlier products, it was a separate component that ran under the OS; for example, LAN Server required OS/2, and LANtastic required DOS.

Systems

)The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers

Network Administrator

A person who manages a local area communications network (LAN) or wide area network (WAN) for an organization. Responsibilities include network security, installing new hardware and applications, monitoring software upgrades and daily activity, enforcing licensing agreements, developing a storage management program and providing for routine backups, not to mention ensuring that it is up and running all the time.

Secondary Storage

Disk Caching

A cache that stores copies of frequently used disk sectors in random access memory (RAM) so they can be read without accessing the slower disk




File Compression

File compression is commonly used when sending a file from one computer to another over a connection that has limited bandwidth. 






File Decompression

The compression of data in a file, usually to reduce storage requirements




Internet Hard Drive

The sole purpose of an Internet hard drive is to offer a means of accessing your computer files (pictures, documents, music, videos, etc.) from any computer, as long as that computer has access to the Internet
.


Optical Disc Drive

A storage medium from which data is read and to which it is written by lasers. 


Solid State Storage

Solid-state storage is a nonvolatile, removable storage medium that employs integrated circuits (ICs) rather than magnetic or optical media.

Input and Output

Ergonomic Keyboard

A keyboard that separates the keys into two halves shaped like a wide "V." Some keyboards have a fixed layout, while others are movable. To the touch typist, the layout feels odd at first, but it puts less stress on the hands and wrist and winds up being comfortable for most people.


Inkjet Printer

A printer that forms an image by using electromagnetic fields to guide electrically charged ink streams onto the page.




Laser Printer

A printer that uses a laser to produce an image computer on a rotating drum before electrostatically transferring the image to paper.


Magnetic Ink Character Recognition

Ink containing magnetic particles to permit reading of printed characters by a magnetic character reader as well as by humans.




Optical Character Recognition

Often abbreviated OCR, optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the can manipulate (for example, into ASCII codes).



Optical Mark Recognition

 OMR technology scans a printed form and reads predefined positions and records where marks are made on the form. This technology is useful for applications in which large numbers of hand-filled forms need to be processed quickly and with great accuracy, such as surveys, reply cards, questionnaires and ballots