Communication and Network

Physical Connection

Twisted-pair cable(Telephone lines)

Twisted pair cable consists of two independently insulated wires twisted around one another. It is one of the cable type that used in telecommunication for very long time. Cable twisting helps to reduce noise pickup from outside sources and crosstalk on multi-pair cables. While twisted-pair cable is used by older telephone networks and is the least expensive type of local-area network cable, most networks contain some twisted-pair cabling at some point along the network.

Coaxial cable

A coaxial cable be composed of two conductors that share a common axis. It used to carry radio signals, video signals, measurement signals and data signals. Coaxial cable are typically characterized with the impedance and cable loss. Although it more expensive than standard telephone wire, 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.
Optical fiber carries much more information than conventional copper wire and is in general not subject to electromagnetic interference and the need to retransmit signals. Now, most telephone company long-distance lines are made by optical fiber.

Computer Networks

Node

In a networks, node is a connection point, is either a redistribution point or a communication endpoint. In general, 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. Web browser is a client in its relationship with the computer that is getting and returning the requested HTML file.

Server

A server is a computer or device on a network that manages network resources. A network server is a computer designed to process requests and deliver data to other computers over a local network or the Internet, it is include Web servers, proxy servers, and FTP servers.

Hub

Hub is a common connection point for device in a network. In data communications, a hub is a place of convergence where data arrives from one or more directions and is forwarded out in one or more other directions. Hubs are commonly used to connect segments of a local area network.




Network Interface Card (NIC)

NIC is an expansion board which you insert into a computer so that the computer can connected to a network. Most NIC are designed for a particular type of network, such as protocol and media, although some can serve multiple networks.



Network Operating System (NOS)

NOS is an operating system that includes special functions for connecting computers and devices into a local-area network. NOS is also designed for client computers and provide functions so the distinction between network operating systems and stand alone operating systems.



Host Computer

Host computer is a computer system that is accessed by user who are working at a remote location. Basically, this term is used when there are two computer systems connected by modems and telephone lines.

Network Manager

Network Manager is a set of co-operative tools that make networking simple and straightforward. Either wireless or wired, network manager allows you to quickly move from one network to another network.

Secondary Storage

Disk Caching

Disk cache is a mechanism for improving the time it takes to read from or write to a hard disk. Nowadays, 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). A portion of RAM used to speed up access to data on a disk.

Redundant Arrays of Inexpensive Disks(RAID)

RAID is a way of storing the same data in different places on multiple hard disks. It is also 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. When data is placing on multiple disks, input and output operations can overlap in a balance way. Besides that, it also can improve performance.

File Compression and Decompression

Input and Output

Magnetic Ink Character Recognition(MIRC)

In computing, MIRC is a character recognition system that using special ink and character which can read and magnetised automatically. The banking industry use MICR to print details on cheques to enable automatic processing because MIRC uses magnetically chargeable ink or toner to print the numbers and special characters on the bottom of checks or other financial transaction documents and are therefore ideal for marking and identifying the account and sort code numbers on cheques.

Optical-Character Recognition(OCR)

Optical Character Recognition is the recognition of printed or written text characters by a computer. This involves photoscanning of the text character-by-character, analysis of the scanned-in image, and translation of the character image into character codes, such as ASCII, commonly used in data processing. When a character is recognized, it will converted into an ASCII code. The libraries are using OCR to digitize and preserve their holdings. OCR is also used to process checks and credit card slips and sort the mail.

Optical-Mark Recognition(OMR)

Optical Mark Recognition also called Optical Mark Reading. It is a technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms and it's also a process of capturing human-marked data from document forms such as surveys and tests. OMR technology scans a printed form, reads predefined positions and records where marks are made on the form.

Dot-matrix printer

Dot matrix printer also called impact matrix printer. It is a the type of computer printer that produces characters and illustrations by striking pins against an ink ribbon to print closely spaced dots in the appropriate shape, much like a typerwriter. Although dot-matrix printers are relatively expensive, it do not produce high-quality output. However it cannot produce high-quality output but it can print to multi-page forms that laser and ink-jet printers cannot do. Dot-matrix printers have two important characteristics that are speed and print quality.

Plotter

A device that draws pictures on paper based on commands from a computer. There are two types of main plotters, pen plotters and electrostatic plotters.Plotters are different from printers because they draw lines using a pen and they can produce continuous lines but printers can only simulate lines by printing a closely spaced series of dots. Multicolour plotters use different colour pens to draw different colours. Plotters are more expensive than printers because they are used in engineering application where precision is mandatory.

Photo Printer

Photo printer usually is a injek printer. It is a printer specialized for smaller prints such as 4x6" and 5x7". Photo printer is specifically designed to print high quality digital photos on photo paper and it usually have a very high number of nozzles and are capable of printing droplets as small as 1 picoliter.

Portable Printer

Portable printer is useful for people that are travelling but who need to work while on the go because is light weight and easy to carry.It just like with laptop computers and the smaller notebooks a reduction in size will more than like reduce the power and the features, while raising the price on the product.

Fax Machine

Fax machine is a telecomunication technology that can send or receive pictures and text over a telephone line. Fax machines work by digitizing an image,it dividing it into a grid of dots. In this way, the fax machine translates a picture into bit map that can be transmitted like computer data. A fax machine reads the incoming data and translates the bitmap into dots, and reprints the picture.

Multifunctional Device

A Multifunctional Device is an office machine which incorporates the functionality of multiple devices in one. It is also a single device that serves several functions. Typically, multifunctional device act as a printer, scanner, fax machine and also a photocopier. It become popular for SOHO user is because it more cheaper than
buying four separate devices.

Internet Telephones

Internet telephones are a category of hardware and software that enables people to use the Internet as a transmission medium for telephone calls. For people who have free or fixed-price Internet access, internet telephones software can provides free telephone calls anywhere in the world. Internet telephones do not have the same quality of telephone service as direct telephone connections.

System Unit

Expansion Card
Expansion card is an eletronic circuit board. It installed into expansion slots of a computer motherboard and adds functionally in to a desktop computer. Expansion card also known as add-on card, intenal card or interface adapter.For example, a user may add a new graphic card to his computer to give it more 3D graphics processing power.



Network Interface Card

A network interface card(NIC) is a computer circuit board or card that is installed into computer so that it can be connected to a network. NIC also is a device that allows computer to be joined together in a local area network(LAN). Networked computers communicate with each other by using a given protocol or agreed-upon language for transmitting data packets between the different machines, known as nodes. The network interface card acts as the liaison for the machine to both send and receive data on the LAN.


Cache Memory

Cache memory is random access memory (RAM) that a computer microprosessor can access more quickly than regular RAM.Cache memory is extremely fast memory that is built into a computer’s central processing unit (CPU), or located next to it on a separate chip.The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cache memory is the CPU does not have to use the motherboard’s system bus for data transfer.


Plug&Play

In computing, 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.Plug and Play (PnP) is a capability developed by Microsoft for operating systems that gives users the ability to plug a device into a computer and let the computer recognize that the device is there.


Sockets
A socket is a single connection between two network applications. These two applications run on different computers, but sockets can be used for interprocess communication on a single computer. Computer sockets are the built-in interfaces on motherboards that can accept various hardware components. The compatible devices will communicate with the system to provide functionality when they are plugged into computer sockets. For example,dial-up modems, graphics cards and sound cards.


Chips(computer-chips)

A computer chip is a small electronic circuit, also known as an integrated circuit. It is one of the basic components of most kinds of electronic devices, especially computers.Computer chips are small and made by semiconductors that is usually composed of silicon, on which several tiny components including transistors are embedded and used to transmit electronic data signals.


Slots
In computing, a slots or expansion slots are the opening in the computer where you can insert a printed circuit board. It's allow us to expand the capabilities of a computer, for instance, more memory, graphics capabilities. The boards that insert into the expansion slots are called expansion boards, expansion cards, add-ins, or add-ons.



Buslines
In computing, a bus is a subsystem that transfers data between computer components inside a computer or between computers.The bus lines are the communicating electronic lines that connect different parts of the CPU to various other parts. It also link the CPU to different parts on the system board of computer.



Serial Port

In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at time.Most serial ports on personal computers conform to the RS-232C or RS-422 standards. A serial port is a general-purpose interface that can be used for almost any type of device, including modems, mice, and printers.



Parallel Port

Parallel port is a simple and inexpensive tool for building computer controlled devices and projects. It is also known as a printer port or Centronics port. A parallel interface for connecting an external device such as a printer. Most personal computers have both a parallel port and at least one serial port.

Universal Serial Bus(USB)

An external bus standard that supports data transfer. It also 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 also supports Plug-and-Play installation and hot plugging

Firewire port

FireWire is some type of Serial Port which uses the serial bus interface standard for high speed data transfer. The FireWire port has been in common use since 1995, it's began to include the port on a number of digital camcorders. Today, the FireWire port is used on a number of other devices.

The Internet,The Web and Electronic Commerce

HTML

HTML is stands for Hyper Text Markup Language.It is not a program,is a markup language for web pages.With HTML we can create our own page. HTML does not hold to that pattern and allows the person to view the World Wide Web page anywhere, any time they want.



JAVASCRIPT

Javascript is a programming language that is use to make web pages interactive.It runs on visitor's computer and does not require constant downloads from web site. JavaScript use in Web site development to do such things as change a formatted date on a Web page automatically, cause a linked-to page to appear in a popup window and cause text or a graphic image to change during a mouse rollover.

Applets

An applet is a program which is written in the Java programming language, it can be included in HTML page, much in the same way an image is included in a page. It is also a program that designed to be executed from within another application. Applets are different with apllications because it cannot be executed directly from the operating system. A well-designed applet can be invoked from many different applications.

Business to consumer(E-Commerce)

Business to consumer(B2C) is a conduct between companies and individual consumers such as the exchanges information, services and product. B2C is retailing part of E-commerce.

Consumer to Consumer(E-Commerce)

Consumer to consumer(C2C) sometimes also refer to peer to peer(P2P). It exchanges the transactions between and among consumers. These transactions can also include third party and usually in the form of those who facilitate the marketplace such as EBay. The exchanges of C2C can include classified advertisement, music, file sharing, career, job websites and also personal services such as dating websites. C2C also has given online shopping and trading a new dimension.

File Transfer Protocol(FTP)

FTP is a standard protocol. It is a simple way to exchange files between computers on the internet. FTP works as the same way with HTTP which is transfering Web pages from a server to a user's browser. It is also works athe same way with SMPT for transferring electronic mail across the Internet.

Most commonly, FTP is used to download a file from a server or upload a file to a server by using the internet.

Filters

In computer programming, filters are a program that accept certain type of data as input to transforms it into some manner and then output the transformed data. This term was used in UNIX systems but is now used in other operating systems. Usually, a filter does not have input or output operation on its own. Sometimes filters are use to remove or insert headers or control characters in data.

Careers in IT

WEBMASTER

Webmaster is a person who maintaining a website.They also an Internet consultancy and implementation service.Besides that,they also offer total Internet solutions. Webmaster also called web architect,web develop,site author,web administrator or(informally)webmeister.Webmaster's duties include ensuring that the web server,hardware and software are operating accurately,designing the website such as e-bay and blogger,generating and revising web pages,replying to user comment and examining traffic through the site.

COMPUTER SUPPORT SPECIALIST

Computer Support Specialist known as help-desk technicians.They have to learn the technical and communication skills because they need to help customers and co-workers with hardware and software problembs.Computer Support Specialist has provides technical assictance and support to customers and other users that deal with hardware and software issues. They usually resolves computer issues by telephone or by direct end user dekstop.

TECHNICAL WRITER

Technical writer is a professional writer who designs,write,creates,maintains and updates technical documentation.Among of their duties are online help,user guides,white papers,design specifications,system manuals and other documents.They work for book,magazine or newspapper publisher and may be employed in other industries. They also work as freelance writers. Their salary are paid by the jobs or by the hour.Technical writer also hired to do specific jobs such as writing about a new high-tech product or advancement.

SOFTWARE ENGINEER

Software engineer is the application of a systematic,displined,quantifible approach to the development,operation and maintenance of software.Their work activities include researching,designing and wrting new software programs,testing new programs and fault finding,maintaining systems by monitoring and correcting software defects.They also solve problems and think laterally as part of a team or individually to meet the needs of the project.They work as employees or contractors.They also work for themselve as freelancers.

NETWORK ADMINISTRATOR

They are modern profession responsible for the maintenance of computer hardware and software that comparies computer network.They related to the network specialist or network analyst who con concentrates on network design and security. They also the one who responsible for the security of the network so they setting up password for individually and determining which files or programes to each person is allowed to use.

DATABASE ADMINISRATOR

They are the one who are responsible for the performance,intergrity and security of database. According to the technology of database management systems,the role of the database administrator has changed as well as the needs of the owners of the database.The database approach the principles such as data remains consistent across the database,data is clearly defined,user access data concurrently and provision for data security and recovery control.


SYSTEM ANALYST

System analyst is a person who do research,plan,coordinate and recommend software and system choices to meet an organization's business requirements.Basically,they performs interact with customers and designers to know their requirements and to convey the possible interface of the software.On the other hand,they perform system testing with sample,implement the new system and prepare high quality documentation.

PROGRAMMER

A programmer is someone who write computer software.There are various types programmer such as game programmer and computer programmer. Game programmer is a software engineer who primarily develops videos games or related software such as game development tools.A game programmer is not same as game designer. Althought many designers are also programmers but not at all are the same.It is rare for the person to serve both roles in modern professional games. A computer programmer is someone who designs software programs. In the majority of cases, the computer programmer also designs a graphical user interface for the non-technical users so that they can use the software easily.