Communication and Network

Modulation
Modulation is the addition of information (or the signal) to an electronic or optical signal carrier. Modulation can be applied to direct current (mainly by turning it on and off), to alternating current, and to optical signals. One can think of blanket waving as a form of modulation used in smoke signal transmission (the carrier being a steady stream of smoke).

Demodulation
Demodulation is the act of extracting the original information-bearing signal from a modulated carrier wave. A demodulator is an electronic circuit (or computer program in a software defined radio) that is used to recover the information content from the modulated carrier wave.

Bandwidth
Bandwidth is often used as a synonym for data transfer rate - the amount of data that can be carried from one point to another in a given time period (usually a second). This kind of bandwidth is usually expressed in bits (of data) per second.

TCP/IP
TCP/IP model is a description framework for computer network protocols created in the 1970s by DARPA, an agency of the United States Department of Defense. It evolved from ARPANET, which was the world's first wide area network and a predecessor of the Internet. The TCP/IP Model is sometimes called the Internet Model or the DoD Model.

Node
In networks, a processing location. A node can be a computer or some other device, such as a printer. Every node has a unique network address, sometimes called a Data Link Control (DLC) address or Media Access Control (MAC) address.

Client
A client is the requesting program or user in a client/server relationship. For example, the user of a Web browser is effectively making client requests for pages from servers all over the Web. The browser itself is a client in its relationship with the computer that is getting and returning the requested HTML file. The computer handling the request and sending back the HTML file is a server.

Server
A computer or device on a network that manages network resources. There are many different types of servers.

Network Operating Systems
An operating system that includes special functions for connecting computers and devices into a local-area network (LAN). The term network operating system, however, is generally reserved for software that enhances a basic operating system by adding networking features.

Network Administrator
A network administrator is a person responsible for the maintenance of computer hardware and software that comprises a computer network. This normally includes deploying, configuring,maintaining and monitoring active network equipment.

Secondary Storage

Disk caching

A soft disk cache works by storing the most recently accessed data in the RAM cache. When a program needs to access new data, the operating system first checks to see if the data is in the cache before reading it from the disk. Because computers can access data from RAM much faster than from a disk, disk caching can significantly increase performance. Many cache systems also attempt to predict what data will be requested next so they can place that data in the cache ahead of time.

File compression

File compression is the practice of packaging a file or files to use less disk space. The File Compression category includes software programs that will archive your files and extract archived files such as ZIP and RAR files. Many products in this category let you manage files and protect them with encryption. Notable titles include WinZip, WinRAR, and 7-Zip.

Internet hard drive
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

Optical disc drive (ODD) is a disk drive that uses laser light or electromagnetic waves near the light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only read from discs, but recent drives are commonly both readers and recorders. Recorders are sometimes called burners or writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives.

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  Solid-state storage

  Solid-state storage is a nonvolatile, removable storage medium that employs integrated circuits (ICs) rather than magnetic or optical media. It is the equivalent of large-capacity,nonvolatile memory. Examples include flash memory Universal Serial Bus (USB) devices and various proprietary removable packages intended to replace external hard drives.
  

  

  
  

Input and Output

Ergonomic Keyboard
An ergonomic keyboard is a computer keyboard that are specially designed with ergonomic considerations to decrease muscle strain and a host of related problems. This keyboard is tyipically designed in a V shape to enable right and left hands to type at a slight angle more natural to the human form.

Ink-jet printer
An ink-jet printer is a type of computer printer that creates a digital image by propelling droplets of ink onto a paper. This printer seems to be the most commonly used type of printer. Ink-jet printers are capable of producing high quality print approaching that produced by laser printers.

Laser Printer
A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers (MFPs), laser printers gives a xerographic printing process, but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.

Magnetic-ink character
In computing, a technique that enables special characters printed in magnetic ink to be read and input rapidly to a computer. MICR is used extensively in banking because magnetic-ink characters can be machine-read with much greater accuracy than human reading or otheroptical character recognition (OCR) systems, and are therefore ideal for marking and identifying the account and sort code numbers on cheques. 

Optical-character recognition
Optical-character recognition is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text. It is widely used to convert books and documents into electronic files, to computerize a record-keeping system in an office, or to publish the text on a website. OCR makes it possible to edit the text, search for a word or phrase, store it more compactly, display or print a copy free of scanning artifacts, and apply techniques such as machine translation, text-to-speech and text mining to it.


Optical-mark recognition
Optical-mark recognition is the process of capturing human-marked data from document forms such as surveys and tests.