Network Terms

Twisted-Pair Cable
Twisted-pair cables is a type of wiring that consists of two cables that is twisted together to cancel out Eloctromagnetic Interference (EMI) from external sources. Most networks contain some twisted-pair cabling at some point along the network while twisted-pair cable is used by older telephone networks and is the least expensive type of LAN cable.

Coaxial Cable
A type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire. The shield minimizes electrical and radio frequency interference. Coaxial cable (or "coax") is the most common cable used for transmitting video signals. The name "coaxial" refers to the common axis of the two conductors. It is widely used for computer networking as it is much less susceptible to interference and can carry much more data.

Fiber-Optic Cable
Fiber-Optic cable is a technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves. The main disadvantage of fiber optics is that the cables are expensive to install. In addition, they are more fragile than wire and are difficult to splice.

Node
Node is a region in an electrical circuit where there is no change in potential. Node is also a connection point, either a redistribution point or an end point for data transmissions. In general, a node has programmed or engineered capability to recognize and process or forward transmissions to other nodes.

Client
A client is an application or system that accesses a remote service on another computer system, known as a server, by way of a network. The term was first applied to devices that were not capable of running their own stand-alone programs, but could interact with remote computers via a network. These dumb terminals were clients of the time-sharing mainframe computer.

Server
A server is an application running on a computer that delivers a service. For example, a web server will deliver web pages when requested by a browser (called client in this context). The way a server and a client dialogs is called a protocol. For instance, HTTP is the protocol used between a browser and a web server. Among the many services provided by the Internet servers are:
1) World Wide Web
2) the domain name system
3) e-mail
4) FTP file transfer
5) chat and instant messaging
6) voice communication
7) streaming audio and video
8) online gaming


Hub
Hub is a common connection point for devices in a network and commonly used to connect segments of a LAN. It also contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.


Network Interface Card ( NIC)
NIC is an expansion board you insert into a computer so the computer can be connected to a network. Most NICs are designed for a particular type of network, protocol, and media, although some can serve multiple networks.

Network Operating System (NOS)
NOS is a network operating system. A network operating system implements protocol stacks as well as device drivers for networking hardware. Some network operating systems, like Windows 98 Second Edition, also add custom networking features like Internet Connection Sharing (ICS).

Host Computer


Network Manager

Secondary Storage

Disk Caching
Disk Caching is a process for improving the time it takes to read from or write to a hard disk.The disk cache is usually included as part of the hard disk. A disk cache can also be a specified portion of random access memory (RAM).
The disk cache holds data that has recently been read and, in some cases, adjacent data areas that are likely to be accessed next. Write caching is also provided with some disk caches.

Redundant arrays of inexpensive disks

(RAID)
RAID is a technology that allowed computer users to achieve high levels of storage reliability from low-cost and less reliable PC-class disk-drive components, via the technique of arranging the devices into arrays for redundancy.
For the large business organizations, which not only need to store terabytes of invaluable data but access them frequently as well. These organizations cannot afford to let their systems go offline even for a short duration of time. Moreover they cannot even think of losing even small amount of data due to disk failure or for that matter any other reason.


File compression and decompression

File Compression is particularly useful in communications because it enables devices to transmit or store the same amount of data in fewer bits. It is also widely used in backup utilities, spreadsheet applications, and database management systems.

File decompression is a technical that change the information in a computer document back into a form that can be easily read or used, when the information was stored on the computer in a special form that used less space on the computer's memory.

Input and Output

Magnetic Ink Character Recognition (MICR)

MICR is a character recognition technology used primarily by the banking industry to facilitate the processing of cheques and allows computers to read information (such as account numbers) off of printed documents. MICR font is usually used to print checks, deposit slips, mortgage coupons, etc.

There are various types of MICR fonts:

• MICR E-13B font is used in the Canada, Panama, Puerto Rico, UK, and the United States.
  
• MICR CRC-7 was created according to the ISO standards and is a font used in France, Mexico, Spain, and most other Spanish speaking countries.
  

Optical-Character Recognition (OCR)

OCR is the mechanical translation of images of handwritten, typewritten or printed text (usually captured by a scanner) into machine-editable text.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.

The potential of OCR systems:

• They enable users to harness the power of computers to access printed documents.
  
• They are being used in the legal profession, where searches that once required hours or days can now be accomplished in a few seconds.
  

 

Optical-Mark Recognition (OMR)

OMR is the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms which it was distinguished from OCR that do not required any recognition engine.

OMR is useful for applications:

• Large numbers of hand-filled forms need to be processed quickly and accurately, such as surveys, reply cards, questionnaires and ballots.
  

 

Dot-matrix Printer

Dot-matrix Printer which also known as impact matrix printer is a type computer printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a type writer. These printers can create carbon copies and carbon-less copies because the printing involves mechanical pressure.

Dot-matrix printers vary in two important characteristics:

• Speed: Given in character per seconds (cps), the speed can vary from about 50 to over 500 cps. Most dot-matrix printers offer different speeds depending on the quality of print desired.
  
• Print quality: Determined by the number of pins (the mechanisms that print the dots), it can vary from 9 to 24. The best dot-matrix printers (24 pins) can produce near letter-quality type, although you can still see a difference if you look closely.
  

 

Plotter

A plotter is a vector graphics printing devices to print graphical plots that connects to computer. Plotters differ from printer in that they draw lines using a pen which can results a continuous lines, whereas printers can only simulate lines by printing a closely spaced series o dots. Multicolor plotters use different-colored pens to draw different colors.

There are two types of main plotters:

• Pen plotters
  
• Electrostatic plotters.
  

 

Photo Printer

A photo printer is a printer (usually an inkjet printer) that is specifically designed to print small and high quality digital photos on photo paper (4x6" and 5x7"). These printers usually have a very high number of nozzles and are capable of printing droplets as small as 1 picoliter.

 

Portable Printer

Portable is used as electronics miniaturizes and increases in quality and cropping up new novelties. This technology can print from camera phones, digital camera or memory cards.

Fax Machine

A fax machine is a device that prvided scan, transmits, receives and prints documents (faxes) transmitted by telephone and allows the user to fax information over a communication line. A fax machine is one of the most invaluable methods of transmitting information that was ever invented. It has allowed transactions ranging from sending letters and photos between loved ones to finalizing major corporate mergers.

Multifunctional Device

Multifunctional device is a device that serves several functions, including printing. In short, it can act as a printer, a scanner, a fax machine and a photocopier. 

The disadvantages of combining all these functions in one device are:

• If the device breaks, you may lose all of its functions at the same time.
  
• You can only do one operation at a time. For example, you can't print a document and receive a fax at the same time.

Internet Telephones

An Internet phone service uses the Internet to send voice instead of using phone lines. Home services have softphones: your computer becomes your telephone, and you talk via a handset or a headset plugged into USB ports. Internet telephony products are called IP telephony, Voice over the Internet (VOI) or Voice over IP (VOIP) products.

There are many Internet telephony applications available:

• Popular web browsers- CoolTalk and NetMeeting.
• stand-alone products.

Voice Over Internet Protocol (VOIP)

VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio via an audio stream.

Codec use is varied between different implementations of VoIP (and often a range of codecs are used); some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs.

System Unit

Expansion Card
An expansion card is an electronic board or card added in a desktop computer or other non-portable computer to give that computer a new ability, such as the ability to connect to another computer using a network cable.

Network Interface Card

A network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network. Personal computers and workstations on a local area network (LAN) typically contain a network interface card specifically designed for the LAN transmission technology, such as Ethernet or Token Ring. Network interface cards provide a dedicated, full-time connection to a network.

Cache Memory
Cache memory is random access memory (RAM) that a computer microprocessor can access more quickly than it can access regular RAM. As the microprocessor processes data, it looks first in the cache memory and if it finds the data there (from a previous reading of data), it does not have to do the more time-consuming reading of data from larger memory.

Plug & Play
Plug and play is a term used to describe the characteristic of a computer bus, or device specification, which facilitates the discovery of a hardware component in a system, without the need for physical device configuration, or user intervention in resolving resource conflicts.

Sockets
A socket is an endpoint for communication between two machines.
The actual work of the socket is performed by an instance of the SocketImpl class. An application, by changing the socket factory that creates the socket implementation, can configure itself to create sockets appropriate to the local firewall.

Chips (Computer-chips)
A small piece of semiconducting material (usually silicon) on which an integrated circuit is embedded. A typical chip is less than ¼-square inches and can contain millions of electronic components (transistors). Computers consist of many chips placed on electronic boards called printed circuit boards.
Example of chips: CPU chips(microprocessors) contain an entire processing unit, whereas memory chips contain blank memory.

Slots
Slots comprises the operation issue and data paths machinery surrounding a collection of one or more functional units (FUs) which share these resources. The term slot is common for this purpose in the VLIW world where the relationship between operation in an instruction and pipeline to execute it is explicit. In dynamically scheduled machines the concept is more commonly called an execute pipeline.

Bus lines
The bus lines are the communicating electronic lines that connect different parts of the CPU to various other parts. In addition, the bus lines also link the CPU to different parts on the system board of your computer. The data flows in the form of bits along the bus lines. The bus lines are like multilane pathway which means that the more bus lines are on the system the greater is the rate of transfer of data along the bus, which means that the computer can run efficiently and will perform the operations at a faster rate.

Serial Port

Serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port).[1] Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals and various peripherals.

Parallel Port

A parallel port is a type of interface found on computers (personal and otherwise) for connecting various peripherals. It is also known as a printer port or Centronics port. The IEEE 1284 standard defines the bi-directional version of the port.


Universal Serial Bus
USB (Universal Serial Bus) is a way of setting up communication between a computer and peripheral devices. USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals.For many of those devices, USB has become the standard connection method. USB was designed for personal computers, but it has become commonplace on other devices such as PDAs and video game consoles, and as a power cord between a device and an AC adapter plugged into a wall plug for charging.

Firewire Port
FireWire is Apple Computer's version of a standard, IEEE 1394, High Performance Serial Bus, for connecting devices to your personal computer. FireWire provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps (megabits per second). The standard describes a serial bus or pathway between one or more peripheral devices and your computer's microprocessor.

The internet,the web and Electronic Commerce

HTML
HTML is a language, which makes it possible to present information (e.g. scientific research) on the Internet.
The purpose was to make it easier for scientists at different universities to gain access to each other's research documents.
What you see when you view a page on the Internet is your browser's interpretation of HTML. To see the HTML code of a page on the Internet, simply click "View" in the top menu of your browser and choose "Source".

Javascript
JavaScript is a scripting language used to enable programmatic access to objects within other applications.
It is primarily used in the form of client-side JavaScript for the development of dynamic websites.

Applets
An applet is a program written in the Java programming language that can be included in an HTML page, much in the same way an image is included in a page. When you use a Java technology-enabled browser to view a page that contains an applet, the applet's code is transferred to your system and executed by the browser's Java Virtual Machine (JVM).

Business-to-Consumer E-Commerce

(B2C, sometimes also called Business-to-Customer) describes activities of businesses serving end consumers with products and/or services.

Example: A person buying a pair of shoes from a retailer. The transactions that led to the shoes being available for purchase, that is the purchase of the leather, laces, rubber, etc. as well as the sale of the shoe from the shoemaker to the retailer would be considered (B2B) transactions.

Consumer-to-Consumer E-Commerce
(C2C) (or citizen-to-citizen) electronic commerce involves the electronically-facilitated transactions between consumers through some third party.
Example: online auction, which a consumer posts an item for sale and other consumers bid to purchase it; the third party generally charges a flat fee or commission. The sites are only intermediaries, just there to match consumers. They do not have to check quality of the products being offered.


File Transfer Protocol (FTP)
A standard network protocol used to exchange and manipulate files over a TCP/IP based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server applications.

Filters

A program that accepts certain type of data as input, transforms it in some manner and then outputs the transformed data.

For example, a program that sorts names is filter because it accepts the names in unsorted order, sort them, and outputs the sorted names.

Careers in IT

Webmaster
* The role of the person is responsible for the development and maintenance of the web servers and web pages at a website.The term does not imply any particular level of skill or mastery.

Computer Support Specialist
*A person who assists users who are having problems with software, computers or peripherals such as printers or scanners.
Some of them assist companies' customers, while other provide support in house to corporate or institutional staff.
Those who provide help over the phone, via online chat or email, are called help desk technicians.

Technical Writer
* The person responsible for writing hardware and software documentation, online help, technical definitions and technical product descriptions on Web sites.
Quite often,they are given the task of documenting an application at the last minute,given a little of time for a through understanding of all the options only and let alone time for others to read and edit the material before it is published.

 Software Engineer
* A person who designs and programs system-level software, such as operating systems, database management systems (DBMSs) and embedded systems.

The title is often used for programmers in the software industry who create commercial software packages, whether they be system level or application level.

Network Administrator
* A person who manages a communications network within an organisation. Responsibilities include network security, installing new applications, distributing software upgrades, monitoring daily activity, enforcing licensing agreements, developing a storage management program and providing for routine backups.

 Database Administrator
* A person responsible for the design and management of one or more databases and for the evaluation, selection and implementation of database management systems.

In smaller organisations, the data administrator and database administrator are often one in the same; however, when they are different, the database administrator's function is more technical. The database administrator would implement the database software that meets the requirements outlined by the organisation's data administrator and systems analysts.

System Analyst
* Interdisciplinary branch of science, dealing with analysis of systems, often prior to their automation as computer systems, and the interactions within those systems.

This field is closely related to operations research.

 Programmer
* A person who designs the logic for and writes the lines of codes of a computer program.

Programming is the heart and soul of developing computer applications, and programmers are the most misunderstood people in the business.

They are constantly being criticized for taking longer to write a program than they initially estimated.