Communication and Network

Physical Connection
Data packets are transmitted between computers on the network either as electrical signals in electric wires, as light signals in fibre optic cables, or as electromagnetic waves through space. The physical connection determines the kind of cable used, the way the cable is configured and the way information is transmitted over the cable.

• Twisted Pair refers to the use of cables that contain insulated copper wires twisted together in pairs for the physical layer of an Ethernet network—that is, a network in which the Ethernet protocol provides the data link layer. Twisted-pair cable is used by older telephone network and is the least expensive type of local area network(LAN) cable, most networks contain some twisted-pair cabling at some point along the network. Other types of cables used for LANs include coaxial cable and fiber optic cables.

• Coaxial cable Coaxial cable is used as a transmission line for radio frequency signals, in applications such as connecting radio transmitter and receivers with their antennas, computer network (Internet) connections, and distributing cable television signals. One advantage of coax over other types of transmission line is that in an ideal coaxial cable the carrying of electromagnetic field signal exists only in the space between the inner and outer conductors . This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other transmission lines, and provides protection of the signal from external electromagnetic interferences. Although it is more expensive than standard telephone wire, it is much less susceptible to interference and can carry much more data.

• Fiber Optic Cable transmit information from one place to another by sending pulses of light through optical fiber. The light in optical fiber forms an electromagnetic carrier wave that is modulated to carry information. Involves the following basic steps: Creating the optical signal involving the use of a transmitter, relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak, receiving the optical signal, and converting it into an electrical signal. Data can be transmitted digitally rather than analogically.

Network terms

• node
• client
• server
• hub
• network interface card( NIC)
• network operating system(NOS)
• host computer
• network manager

Secondary Storage

Disk Caching

A disk cache is a mechanism for improving the time it takes to read from or write to a hard disk and it is usually included as part of the hard disk. A disk cache can also be a specified portion of random access memory (RAM). 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. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data. When a program needs to access new data, the operating system will first checks to see if the data is in the cache before reading it from the disk accessing data from RAM much faster than from a disk, disk caching can significantly increase performance.

Redundant Arrays of Inexpensive disks(RAID)

It's a technology that allowed computer users to achieve high levels of storage reliability from low-cost and less reliable PC-class disk-drive components,through the technique of arranging the devices into arrays for redundancy.Redundancy is achieved by either writing the same data to multiple drives or collecting data across the array, calculated such that the failure of one disks in the array will not result in loss of data. A failed disk may be replaced by a new one, and the lost data reconstructed from the remaining data and the parity data. There are three key concepts in RAID: mirroring, the copying of data to more than one disk; striping , the splitting of data across more than one disk; and error correction, where redundant data is stored to allow problems to be detected and possibly fixed. Different RAID levels use one or more of these techniques, depending on the system requirements. RAID's main aim is either to improve reliability and availability of data, ensuring that important data is available more often than not or merely to improve the access speed to files.

File compression and decompression

Input and Output

Magnetic Ink Character Recognition(MICR)

Magnetic Ink Character Recognition, or MICR, is a character recognition technology usually by the banking industry to facilitate the processing of cheques. The technology allows computers to read information off of printed documents such as account numbers. MICR codes can be easily read by humans unlike barcodes or similar technologies. MICR can be machine-read with much greater accuracy than human reading or other optical character recognition (OCR) systems so therefore it is ideal for marking and identifying the account and sort code numbers on cheques. These characters are printed in special typefaces with a magnetic ink or toner, usually containing iron oxide. As a machine decodes the MICR text, it first magnetizes the characters in the plane of the paper then the characters are then passed over a MICR read head, a device similar to the playback head of a tape recorder. As each character passes over the head it produces a unique waveform that can be easily identified by the system.

Optical-Character Recognition(OCR)

Optical character recognition, is the mechanical or electronic translation of images of handwritten, typewritten or printed text into machine-editable text.Before OCR can be used, the source material must be scanned using an optical scanner to read in the page as a bitmap where software to recognize the images is also required. The OCR software will then processes these scans to differentiate between images and text and determine what letters are represented in the light and dark areas. Multiple algorithms of neural network technology to analyze the light and dark along the side of stroke edge,the line of discontinuity between the text characters, matches to known characters and makes a best guess as to which character it is and the background is added into today's OCR. OCR software then averages or polls the results from all the algorithms to obtain a single reading.

Optical-Mark Recognition(OMR)

Optical Mark Recognition (OMR) is the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms.It requires the image to have high contrast and an easily-recognizable or irrelevant shape. OMR technology scans a printed form and reads predefined positions and records where marks like the bubbles that the applicant fills in to indicate their selections made on the form. This technology is useful for applications in which large numbers of hand-filled forms need to be OMR is usually used for variety of applications as it processed quickly and with great accuracy, such as surveys, reply cards, questionnaires and ballots. The optical mark reader will shines a light beam onto the input document and marks could be detected because less light is reflected back from them than from the paler, unmarked paper.

Dot-Matrix Printer

A dot matrix is a kind of 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 typewriter. Unlike a typewriter, the letters are drawn out of a dot matrix so different kind of fonts and arbitrary graphics can be produced. Each dot is produced by a tiny metal rod, also called a "wire" or "pin". Dot-matrix printers are relatively expensive yet does not produce high-quality output. However, carbon copies of multi-page can be produced which inkjet printers can't do so.

Plotter

It is a device which draws pictures on paper based on the commands from a computer. Plotters is different from printers because they draw lines using a pen, so continuous lines is produce. Whereas printers can only simulate lines by printing a closely spaced series of dots. That's why different-coloured pens are used to draw different colours. Plotters are way expensive than printers and it's usually used in engineering applications where precision and high resolution is mandatory.

Portable Printer

It is a small and lightweight portable printer. It is a miniature of a normal printer,and more likely reduce in power and features. With the introduction of the color printers and the latest photo printers, this has had an impact on the travel printers as well(portable priners).It is used as a tool to print holiday pictures while on vacation as the weight might not be an issue and you’re able to put it into your trolley or suitcase.

Fax Machine

Facsimile means make a copy, or make similiar.Fax machine is a telecommunications technology used to transfer copies of documents using affordable devices operating over the telephone network. It is also known as a telecopier in certain industries because faxes have obvious advantage over postal mail because it is nearly instantaneoussending documents to people at large distances. Yet its disadvantages in quality have relegated it to a position beneath email as the prevailing form of electronic document transfer except where the legal status of a sent fax and its accompanying sending report are desired. Fax machines digitize an image and divide it into a grid of dots where each dot is represented by a bit which has a value of 0 and 1. The fax machine translates a picture into a series of zeros and ones that can be transmitted like normal computer data and on the receiving side, the fax machine reads the incoming data and then translates the zeros and ones back into dots, and reprints the picture out.

Multi Functional Device

Multifunctional devices is one neat, efficient and cost-effective package which bring the worlds of copying, printing, finishing, and scanning together.multifunctional copier increases user productivity. It offer much greater functionality than local or work group printers and are much more cost effective from a total cost of ownership perspective.Users can print many documents over a period of time and then collect them all at once by inputting a PIN number at the multifunctional device and selecting the documents previously sent.

Internet Telephones

Internet telephone refers to communications services such as voice, facsimile, and/or voice-messaging applications which are transported via the Internet, rather than the public switched telephone network (PSTN). Steps involved is convert the analog voice signal to digital format and then translate the signal into Internet Prootocol for transmission and the process is vice versa at the receiving end. Just as with regular telephone service, you pick up the phone to get a dial tone and press numbers on the keypad to call the person you want to talk with.

System Unit

Expansion Card

It's an add-on and internal card. It is an electronic board or card which is installed into the expansion slot of a computer to give the computer a new ability, adds more function to a computer.Video cards and sound cards are common examples of PC expansion cards. A new video card added will enhance the three dimensional graphics processing power of a computer while a new sound card may improve a computer’s audio input.

Network Interface Card

It is used to c0nnect a computer to Ethernet network.the network computers communicate with each other using a given protocolor agreed upon language for transmitting data packets between the different machines known as nodes. the card acts as the liaison for the machine to both send and receive data on the LAN (local area network)


Cache Memory

Random Access Memory 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 finds the previous reading data there which is not time consuming to read data from larger memory. When you turn your computer on and load the operating system, you are loading it into the RAM . RAM can also contain a special area called a disk cache that contains the data most recently read in from the hard disk.Hard drives are very slow compared to the CPU. RAM is much faster tha the hard drive, but still 4-5 times slower than your CPU. Also, RAM is erasedif the power goes off. Cache RAM is extremely fast--it is capable of delivering data at or near the speed of the CPU.


Plug and Play(PnP)

It's a capability developed by Microsoft for its Windows 95 and then later operating systems which gives users the ability to plug a device into a computer and for the computer to recognize the device is there. It tells the software where to find various pieces of hardware such as modems, network cards, sound cards , etc. It match up physical devices with the software which operates them and to establish channels of communication between each physical device and its driver.

Sockets

The processor socket which is also called a CPU socket is the connector on the motherboard that houses a CPU and forms the electrical interface and contact with the CPU. it uses a pin grid array where the pins on the underside of the processor connect to holes in the processor socket.

Chips (computer chips)

Computer chip is a small electronic circuit,which is also known as an integrated circuit, is one of the basic components of most kinds of electronic devices, especially computers. Computer chips are small and are made of semiconductors on which several tiny components including transistors are embedded and used to transmit electronic data signals. They became popular in the latter half of the 20th century because of their small size, low cost, high performance and ease to produce.

Slots

Its an opening in a computer where you can insert a printed circuit board.They are often called expansion slots because they allow you to expand the capabilities of a computer to add more memory, graphics capabilities, and supports for special devices. Boards which is inserted into the expansion slots are called expansion boards, expansion cards , cards, add-ins, and add-ons.

Buslines

Bus lines are the communicating electronic lines which connect different parts of the CPU to various other part on the system board of our computer. Data flows in the form of bits along the bus lines. The bus lines are like multilane pathway so the more bus lines on the system, the faster the data is transfer along the bus, then computer can run efficiently and perform the operations at a faster rate.There are several types of bus lines, some of which are as follows, Industry Standard Architecture, the bus line capacity is 16 bit. Though it is slow, it is still being used. Peripheral Component Interconnect has a speed of 64 bit which is being used widely in personal computers. Accelerated Graphics Port is mostly used for acceleration of graphics performance.

Serial Port

A port, or interface,which can be used for serial communication.A serial port is a general-purpose interface that can be used for almost any type of device, including modems, mouse, and printers and is capable of transmitting one bit at a time. With the introduction of USB, FireWire, and other faster solutions serial ports are rarely used when compared to how often they've been used in the past.

Parallel Port

Parallel port is used for connecting your own circuits to PC. The PC's parallel port can be used to perform hardware interfacing experiments. Due to the simplicity of its implementation, it is often used for interfacing with custom-made peripherals.

Universal Serial Bus

USB (Universal Serial Bus) is a way of setting up communication between a computer and peripheral devices.It is intended to replace varieties of serial and parallel ports. USB has become the standard connection method and can connect computer peripherals such as mouse, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, flash drives, and external hard drives. USB was designed for personal computers, but has become commonplace on other devices such as PDAs and video game consoles. Besides that it also acts as a power cord between a device and an AC adapter plugged into a wall plug for charging. When plugged in, everything configures automatically.

Firewire Port

Firewire ports are forms of a serial port that make use of FireWire technology to transfer data rapidly from one electronic device to another since 1995 to include the port on a number of digital camcorders. Today, the FireWire port is used on a number of other devices. It has the ability to interact with a number of different devices. For example, a FireWire connection can provide an ideal way to connect a scanner to a computer system. Because the transfer rate of a FireWire port can reach up to 400 Mbps, the data transfer is relatively fast and also results in excellent quality.

The internet, the web and electronic commerce

HTML

HTML stands for Hypertext Markup Language.It denotes structural semantics for text such as headings, paragraphs, lists etc as well as for links, quotes, and other items.It is not a programming language but a markup language. A markup language is a set of markup tags
*HTML uses markup tags to describe web pages.
*HTML tags are keywords surrounded by angle brackets
*HTML tags normally come in pairs like and
The first tag in a pair is the start tag, the second tag is the end tag
Start and end tags are also called opening tags and closing tags.

HTML tags, are enclosed by the lesser than (<) and greater than (>) brackets and may be written in capital or lower case letters.It can be used to enhance your web page, format your text using bold headlines, colored HTML table cells, and graphic bullets and/or arrows.

JAVASCRIPT

It 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.It is used to keep the browser from executing a script when the page loads, you can put your script into a function. JavaScript was influenced by many languages and was designed to look like Java, but to be easier for non-programmers to work with.

APPLETS

Applet is a program written in the Java programming language which can be included in an HTML page,just like how an image is included in a page. It is also a small application that performs one specific task; sometimes running within the context a larger program. 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 (B2C)

Business conducted between companies and individual consumers, rather than between two companies. It describes activities of businesses serving end consumers with products services.
An example of a B2C transaction would be 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. It also describe a company that provides goods or services for consumers.

CONSUMER to CONSUMER (e-Commerce)

It means through which consumers interact with other consumers through online auctions and involves all transactions between and among consumers. C2C exchanges can include classified ads, music and file sharing, career and job websites and also personal services such as dating websites. Here consumers can sell goods and services to other consumers. There are millions of sellers with different items to sell and an equally large number of buyers. Finding each other can incur quite a high cost to both buyer and seller, and thus this is why intermediaries like eBay are so important. eBay mediate between consumers who want to buy and sell, and take small cuts of the sellers profit as a fee for bringing their customers to one marketplace. C2C gives many small business owners a way to sell their goods without running a highly profit draining bricks-and-mortar store. The most effective consumer to consumer businesses involve items such as handmade gifts, personal artwork, clothing design, and collectible.


FILE TRANSFER PROTOCOL (FTP)

File Transfer Protocol (FTP)is the simplest way to exchange files between computers on the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server applications.FTP often used as an application component to automatically transfer files for program internal functions and can be used with user-based password authentication or with anonymous user access. FTP is also commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It's also commonly used to download programs and other files to your computer from other servers.

Filters

Filters enables administrators to enforce network usage policies and monitor user behavior.

A Windows driver that adds value to peripheral devices or supports a specialized device in the PC.It is either written by Microsoft or the vendor of the hardware, any number of filter drivers can be added to Windows. Upper level filter drivers sit above the primary driver for the device (the function driver), while lower level filter drivers sit below the function driver and above the bus driver.Filters may work on a certain brand of device such as a mouse or keyboard, or they may perform some operation on a class of devices, such as any mouse or any keyboard. Another type of filter driver is the bus filter driver, which may be added on top of the bus driver. For example, an ACPI bus filter is added to support power management for each device.

Careers in IT

WEBMASTER

Maintaning, managing,organizing and creating websites or webserver are the responsibilites of the WEBMASTER. They ensure the sites goes smoothly so that web users are able to access the website. They also are the one who keep us updated about the site. Webmasters are the one who will give feedbacks to the web users. Besides that they are to ensure the hardware and software are operating accurately.

Computer Support Specialist

Computer support specialist are the ones who helps people with problems about computer and they will teach the users how to use the computer hardware and software.They are like printing, installation of new program, operating systems, word processing, electronic mails. When there any problems encounter, they are the one who solves and fix it. Most of them diagnose the problems in person, via phone, or from remote location. Suppost specialist work within acomputer systems company or for the computer software and hardware vendors.

Technical Writer

Technical authors they translate and organize the complex information into user guides so that users could understand and use the product easily. They put a lot of efforts to analyze scientific knowledge, understand it and then further explain them in simple language which is understandable by everyone. Technical writing also includes creating the documentation for the products and services we use. They must also have the ability to write in a simple, concise and accurate manner, and lastly but not least good research.

Software engineering

Software engineers is someone who develope an assembling large amount of codes into a working applications, update and fixing problems in a program. A certified professionals and skilled in application of engineering discipline on creation of software is the Software engineers. Besides that, a software engineer create software of higher quality, more afordable,maintainable, and quicker to build for end-users. People are always confused between a software engineer and a programmer. A programmer creates the code that runs a program while a software engineer makes the design the programmer implements.

Network Administrator

Network administrator are the one who are responsible in operating and administrating the company’s internal networks, servers, email and network security systems by connecting the necessary hardware and software to the network. They will also forecast any needed improvements, implement any changes and the budgets for it. In major corporations, ensuring the security of stored information and giving access to relevant people - firewall, is the job of a Network Administrator. A network administrator's work usually depends on the size of the network for which he or she is responsible. The smaller the network, the more duties a network administrator handles as he or she might be dealing alone. As for the larger networks, several individuals may perform different tasks related to the network.

Database Administrator

Database administrator are the one who are responsible for the design, development, operation, safeguarding, maintenance, and use of a database. They also ensure that a database is available to the users and programs that need it which includes making backups and archiving data. Besides that they have to monitor to ensure that the database is respondind to the requests quickly.Plus they are also responsible in managing the information within an organization as most companies experience inevitable growth of database. Depending on the company and the department, being a Database Administrator,they can either be highly specialized or vice versa.Yet, this position carries an enormous amount of responsibility.

System Analyst

A system analyst designs and identify new IT solutions to improve business efficiency,productivity and optimizing computer resources. They also specify how the system will perform, and how the user view the data, presenting their design to the client and when it is approved,they work with the client team to implement the solution.If a complex program is needed for the system, the analyst will enlist the help of a computer software engineer to design and write the program.

Programmer

Programmer are someone who writes computer software, they work in large software companies, or even small service firms. Programmer writes, tests, debugs, and maintains detail instructions so that the the computer follow and perform their functions. According to the specifications determined primarily by system analysts or senior programmers, they write programmes accordingly.