Communication and Network

Modulation

It is the transmission of a signal by using it to vary a carrier wave, changing the carrier's amplitude, frequency or phase. Besides that, it is the process of conveying a message signal. Modulation is the process of converting digital signal to analog signal. Modem is the device that is used for the modulation process.

Demodulation

It is a process of retrieving data or message conveyed from the modulator. Besides that, it interprets and changes the signal delivered by the modulator. Demodulation process converts analog signal to digital signal. Modem, the same device used for the modulation process is also used in this process.

Bandwidth

It is a measurement of data that can be carried from one point to another in a given time period. Bandwidth is usually measured in bits (of data) per second (bps). For example, to transfer texts or documents, a slow bandwidth is used and to transfer audio or video files, a wider bandwidth is needed. There are three types of bandwidth which are voiceband (used for dial-up service), medium band (leased lines) and broadband (used for DSL and high capacity transmission).

TCP/IP



Short for transmission control protocol/internet protocol, it is the standard protocol or rules for the Internet. It allows different kinds of computers on different networks to communicate. Therefore, connecting them by a "universal" language. The essential features of TCP/IP is are identification and packetization. Identification is to identify sending and receiving devices whereas packetization reformats the information for transmission across the Internet. For identification, the internet uses IP address to deliver email and locate websites and the domain name server (DNS) converts the text-based adress to IP address. The function is the similar to a postal address. Packetization transmits information through interconnected networks. Before a message is sent, it is reformatted into packets and each packet is sent separately through the Internet. These packets are then reassemble into the correct order when received.


Node

It is a connection point for networks. It can be any device connected to a network. For example, a computer, printer, a data storage device or an active electronic device that is attached to a network. Besides that, it is capable of sending, receiving or forwarding information over a communications channel.

Client

It is a node that requests and uses resources available from other nodes. Basically, a client is a user’s microcomputer. Besides that, a client is capable of obtaining information and applications from a server. Clients make "requests" through a network or networks, and receive "responses" from servers.

Server

It is a a node that shares resources with other nodes. Servers provide essential services across a network through the Internet. There are many servers and each of them are assigned to a specific task. Dedicated servers that are assigned to a specific tasks are  web servers, print servers, and database servers.

Network Operating Systems

It is an operating system that has special functions for connecting computers and devices into a local-area network (LAN). NOS controls and coordinates activities of all computer and devices on the network. Such activities include electronic communication and the sharing of information and resources. Examples of networking operating systems are Novell Netware, Artisoft's LANtastic, Microsoft Windows Server, and Windows NT.

Network Administrator

A computer specialist who manages a communications network in an organization. Responsibilities include implementing new networks, maintaining network operations efficiently and network security. Besides that, installing new hardware and applications, monitoring software upgrades, enforcing licensing agreements, developing a storage management program and providing for routine backups.

Secondary Storage

Disk Caching 

It is a mechanism for improving the time it takes to read from or write to a hard disk. A disk cache can also be a specified portion of RAM. Nowadays, it can be found on hard disk. It also holds data that has recently been read.

File Compression

It helps to reduce  the overall number of bits and bytes in a file so it can be transmitted faster over slower Internet connections, or take up less space on a disk. Most computers have the same information listed over and over again. Therefore, instead of listing the information over and over again, file compression programs lists that information once and then refers back to it whenever it appears in the original program. Compressed files are called "archives" and may contain more than one file. WinZip, WinRar, and 7-Zip are popular types of file archival that all offer data compression.

File Decompression

When compressed files are sent and received by the recipient, the files must be decompressed to be used. When a file archive, such as a .zip or .rar is decompressed it will expand and extract a series of files or folders from that single file. Decompressing files are also known as unzipping or extracting files.

Internet Hard Drive

Its works the same as the hard drive only it has the advantage of users being able to access their files online. Users may upload music, videos, documents or any other files online. There is no limited storage capacity compared to a hard drive. Internet hard drive makes it easier for users as they are able to log in any computer that has an internet connection to access their hard drive.

Optical Disk Drive

It is a 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. It retrieves and stores data on optical discs like CDs, DVDs and Blu-ray discs. Most optical disk drives can play and record a large number of disc formats.

Solid-state Storage

It is a nonvolatile and removable storage medium that employs integrated circuits rather than magnetic or optical media. It also has a nonvolatile memory. Data is stored and retrieved electronically directly from these devices. Examples of solid-stage storages are flash memory cards and memory sticks. This type of storage is compatible with digital cameras, camcorders and computers. 

Input and Output

Ergonomic Keyboard

This keyboard is designed to relieve some of the stress caused by typing due to the usage of fingers, hands and the wrists. It helps as it instills comfort to the users hands and wrists when they type. The "split hands" design is the central feature of the keyboard as it provides a more natural positioning for the hands to be more widely separated when typing. In conclusion, ergonomic keyboards provides a more natural position for typing and helps to reduce muscle stress on fingers, hands and wrists. This type of keyboard is also highly recommended by therapists and health care professionals.

Inkjet Printer

It is a type of printer that works by spraying ionized ink at a sheet of paper. Magnetized plates in the ink's path direct the ink onto the paper in the desired shapes. It is capable of producing high-quality prints. A typical inkjet printer offers a resolution of 300 dots per inch. Inkjet printers are also slower compared to laser printers and requires a special type of ink. The price of this type of printer is also cheaper compared to laser printers.

Laser Printer

It is a type of printer that works by using a focused beam or light to transfer texts and images onto paper. The printer works by having the paper pass through the printer then the laser beam fires at the surface of a cylindrical drum. This drum has an electrical charge (typically positive), that is reversed in areas where the laser beam hits it. By reversing the charge in certain areas of the drum, the laser beam can print patterns (such as text and pictures) onto the cylindrical drum. The pattern is then coated with toners. Laser printers has less image smearing problems because they do not use ink. Laser printers typically have a resolution of 600 dpi (dots per inch) or higher.

Magnetic-ink Character Recognition

Known also as MICR, it is primarily used by the bank industry. The technology allows computers to read information (such as account numbers) off printed documents and can be easily read by humans. MICR characters are printed in special typefaces with a magnetic ink or toner, usually containing iron oxide. The use of magnetic printing allows the characters to be read reliably even if they have been overprinted or obscured by other marks.

Optical-character Recognition

Abbreviated OCR, an OCR system enables you to take a book or a magazine article, feed it directly into an electronic computer file, and then edit the file using a word processor. All OCR systems include an optical scanner for reading text, and sophisticated software for analyzing images. OCR enables users to harness the power of computers to access printed documents.

Optical-mark Recognition

It electronically extracts intended data from marked fields, such as checkboxes and fill-infields, on printed forms. 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 and questionnaires. It is mostly used in schools for multiple-choice tests. The device scans the document and reads the data from the marked fields. The error rate for OMR technology is less than 1%.