BCS,Intro to IT

Whatever brings you here, you are here now!

Monday, October 19, 2009 @ 10:09 PM

Communication and Network

Twisted-pair
Twisted pair cabling is a type of wiring in which two conductors (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from Unshielded Twisted Pair (UTP) cables, and crosstalk between neighboring pairs.

Coaxial Cable
Coaxial cable, or coax, is an electrical cable with an inner conductor surrounded by a tubular insulating layer typically of a flexible material with a high dielectric constant, all of which are surrounded by a conductive layer (typically of fine woven wire for flexibility, or of a thin metallic foil), and finally covered with a thin insulating layer on the outside.

Fiber-optic cable
Fiber optic cable functions as a "light guide," guiding the light introduced at one end of the cable through to the other end. The light source can either be a light-emitting diode (LED) or a laser.

Network Terms
Node
a physical network node may either be a data circuit-terminating equipment (DCE) such as a modem, hub, bridge or switch; or a data terminal equipment (DTE) such as a digital telephone handset, a printer or a host computer, for example a router, a workstation or a server.

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.

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). Among the many services provided by the Internet servers are World Wide Web, the domain name system, e-mail, FTP file transfer, chat and instant messaging, voice communication, streaming audio and video and online gaming.

Hub
A network hub or repeater hub is a device for connecting multiple twisted pair or fiber optic Ethernet devices together and thus making them act as a single network segment.

Network Interface Cord (NIC)
a NIC is also commonly referred to as a network adapter and is an expansion card that enables a computer to connect to a network such as a home network

Network Operating System (NOS)
A networking operating system is an operating system that contains components and programs that allow a computer on a network to serve requests from other computer for data and provide access to other resources such as printer and file systems.

Host Computer
Main or controlling computer connected to other computers or terminals to which it provides data or computing services via a network.

Network Manager
NetworkManager is a software utility aimed at simplifying the use of computer networks on Linux and other Unix-like operating systems.

Monday, October 12, 2009 @ 10:47 PM

Secondary Storage

Disk Caching

Disk caching saves copies of the downloaded files on the hard drive so they doesn't need to be downloaded to be redisplayed. These pages can be viewed by anyone with permission to the cache folder. Pages transmitted with SSL encryption often contain sensitive information and caching of these pages to disk may present a privacy risk. This preference controls whether to cache to disk pages that were transmitted with SSL encryption.

Redundant arrays of inexpensive disks (RAID)

RAID is a method in which information is spread across several disks, using techniques such as disk striping (RAID Level 0) and disk mirroring (RAID level 1) to achieve redundancy, lower latency and/or higher bandwidth for reading and/or writing to disks, and maximize recoverability from hard-disk crashes.

File compression and decompression

File compression can significantly reduce the size of a file (or group of files). Smaller files take up less storage space on the host and less time to transfer over the network, saving both time and money.

Monday, October 5, 2009 @ 10:33 PM

Input and Output

Magnetic Ink Character Recognition (MICR)

MICR is a character recognition used by the banking industry for cheques. The character is read by the computers but it can easily see by our naked eyes. MICR characters are printed in special typefaces with a magnetic ink or toner, usually containing iron oxide.

Optical-Character Recognition (OCR)

OCR is a kind of computer science that reads picture of handwritten, typewritten or printed text into machine-readable code. OCR allows you to take an article and feed directly into an computer file then using a word processor to edit it.

Optical-Mark Recognition (OMR)

Optical-Mark Recognition is the process of capturing human-marked data from document forms. OMR is fast and used for variety applications such as simple surveys, verify presence of signatures or tests.

Dot-Matrix Printer

A kind of printer that produces characters and illustrations by impact and striking pins against an ink ribbon to print closely spaced dots in the appropriate shape. Widely used to print multipart forms and address labels.

Plotter

A plotter is a vector graphics printing device to print graphical plots that connects to a computer. There are two types of main plotters. Those are pen plotters and electrostatic plotters.

Photo Printer

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

Portable Printer

Basically, portable printer's function is as same as the common one. The advantages of portable printer is able to bring along and its more convenience.

Fax Machine

Fax machine are an essential telecommunication device for transmitting and receiving distance static images, forms and documents by way of wire or wireless transmission mode.The advantages of this kind of telecommunication instruments are that images or characters can be transmitted and received. A fax machine transmits a document by producing a graphic image of the document which is converted into a data signal. The data signal is transmitted over conventional phone lines to a receiving fax machine which uses the data signal to drive a printer portion of the receiving fax machine to print an image of the document.

Multifunctional Device

Multifunction Device (MFD), is an office machine which incorporates the functionality of multiple devices in one, so as to have a smaller footprint in a home or small business setting (the SOHO market segment), or to provide centralized document management/distribution/production in a large-office setting. A typical MFP may act as a combination of some or all of the following devices:

Internet Telephones

Internet telephone has the same function of the phone but refers to communication services like voice, facsimile, and voice-messaging application. They are transported via the Internet. The voice communications is delivered over IP networks. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone.

Monday, September 28, 2009 @ 10:13 PM

System Unit

Expansion Card

An expansion card also known as an add-on card, internal card or interface adapter, is an electronic circuit board that can be inserted in a desktop computer for additional functionality and ability to a computer system. For example, a new video card added will enhance the three dimensional graphics processing power of a computer while a new sound cad may improve a computer’s audio input.

Network Interface Card

A network interface card, NIC, is a hardware device that handles an interface to a computer network and allows a network-capable device to access that LAN or local area network. The card also contains the protocol control firmware and Ethernet Controller needed to support the Medium Access Control (MAC) data link protocol used by Ethernet.

Cache Memory

Cache (pronounced cash) memory is extremely fast memory that is built into a computer’s 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 that the CPU does not have to use the motherboard’s system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard’s capability. The CPU can process data much faster by avoiding the bottleneck created by the system bus.

Plug & Play

Plug and Play (PnP) is a capability developed by Microsoft for its Windows 95 and later operating systems that gives users the ability to plug a device into a computer and have the computer recognize that the device is there. Plug and play refers to both the traditional boot-time assignment of device resources and driver identification, as well as to hotplug systems such as USB and Firewire.

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. Each socket is mapped by the operational system to a communicating application process or thread.

Chips (computer-chips)

A computer chip is a small electronic circuit, also known as an integrated circuit, which is one of the basic components of most kinds of electronic devices, especially computers. Computer chips are small and are made of semiconductors that is usually composed of silicon, 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

An opening in a computer where a circuit board can be inserted to add new capabilities to the computer. Nearly all personal computers except portables contain expansion slots for adding more memory, graphics capabilities, and support for special devices. The boards inserted into the expansion slots are called expansion boards, expansion cards , cards , add-ins , and add-ons.

Buslines

In computing, the electrical pathway through which a computer processor communicates with some of its parts and/or peripherals. A bus is a set of parallel tracks that can carry digital signals; it may take the form of copper tracks laid down on the computer's printed circuit boards (PCBs), or of an external cable or connection.

Serial Port

A serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Serial ports are one of the oldest types of interface standards and considered to be one of the most basic external connections to a computer. Data transfer through serial ports connected the computer to devices such as terminals and various peripherals. Serial ports are controlled by a special chip call a UART (Universal Asynchronous Receiver Transmitter).

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. This port will allow the input of up to 9 bits or the output of 12 bits at any one given time, thus requiring minimal external circuitry to implement many simpler tasks. It's found commonly on the back of your PC as a D-Type 25 Pin female connector. There may also be a D-Type 25 pin male connector.

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 such as mice, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, flash drives, and external hard drives.

Firewire Port

The IEEE 1394 interface is a serial bus interface standard for high-speed communications and isochronous real-time data transfer, frequently used by personal computers, as well as in digital audio, digital video, automotive, and aeronautics applications. The interface is known by the brand names of FireWire (Apple), i.LINK (Sony), and Lynx (Texas Instruments). IEEE 1394 replaced parallel SCSI in many applications, because of lower implementation costs and a simplified, more adaptable cabling system. The 1394 standard also defines a backplane interface, though this is not as widely used.

Monday, August 17, 2009 @ 10:23 PM

The Internet, The Web and Electronic Commerce

HTML
HTML, which stands for Hypertext Markup Language, is the language for web pages. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists etc as well as for links, quotes, and other items. It allows images and objects to be embedded and can be used to create interactive forms. It is written in the form of HTML elements consisting of "tags" surrounded by angle brackets within the web page content. It can include or can load scripts in languages such as JavaScript, which affect the behavior of HTML processors like Web browsers, and Cascading Style Sheets(CSS) to define the appearance and layout of text and other material. The use of CSS is encouraged over explicit presentational markup.

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. JavaScript is a dialect of the ECMAScript standard and is characterized as a dynamic, weakly typed, prototype-based language with first-class functions. JavaScript was influenced by many languages and was designed to look like Java, but to be easier for non-programmers to work with.

Applets
An applet is any small application that performs one specific task; sometimes running within the context a larger program perhaps as a plug-in. However, the term typically also refers to programs written in the Java programming language which are included in an HTML page.

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

Consumer-to-Consumer E-Commerce
Consumer-to-consumer (C2C) (or citizen-to-citizen) electronic commerce involves the electronically-facilitated transactions between consumers through some third party. A common example is the online auction, in 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)
File Transfer Protocol (FTP) is a standard network protocol used to exchange and manipulate files over an Internet Protocol computer 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. Client applications were originally interactive command-line tools with a standardized command syntax, but graphical user interfaces have been developed for all desktop operating systems in use today. FTP is also often used as an application component to automatically transfer files for program internal functions. FTP can be used with user-based password authentication or with anonymous user access.

Filters
A filter is a computer program to process a data stream. Some operating systems such as Unix are rich with filter programs. Even Windows has some simple filters built in to its command shell, most of which have significant enhancements relative to the similar filter commands that were available in MS-DOS.

Monday, August 3, 2009 @ 10:27 PM

Career in IT

Webmaster

Basically, webmaster is also called a web architect or site author. Webmaster actually do more than simply write computer codes or update links, their tasks also include make sure the server and browsers can properly handle e-mails, transmit news and download files. Due to the differences operating system such as Windows or Macintosh, webmaster also require to keep up changing technical standards in areas such as HTML, HTTP and XML. The webmaster must also maintain a "firewall" that protects the client's information from hackers or others who may try to steal or destroy it electronically.

Computer support specialist

Computer support specialists help people use computers. When something goes wrong, support specialists figure out why. Then, they try to fix it. Some assist companies' customers, while other provide support inhouse to corporate or institutional staff. Those who provide help over the phone, via online chat or email, are called help desk technicians.

Technical Writer

A technical writer is tasked with writing documentation that explains

technical issues in ways that non-technical people can understand. A technical writer might be responsible for writing the how-to manual for a software application. Technical writers are often copy writers and vice-versa. A good technical writer can write about a complicated technical subject or task in ways that almost anyone can clearly understand. At the same time, precision in technical writing tends to be critical because if anything is described incorrectly, readers may act improperly on what is said, causing mistakes and problems at work.

Software Engineer

A software engineer researches, designs and develops software systems to meet with clients requirements. Once the system had been fully designed software engineers then test, debug, and maintain the systems. Due to the wide variety of work that they can be involved in, they need to have knowledge of a variety of computer programming languages and applications. Software engineering is one of the most popular professions in IT in terms of the numbers employed.

Network Administrator

Network Administrator is a modern profession in charge of the maintanance of computer hardware and software systems that comprises a computer network. This includes activities such as the deployment, configuration, maintanance and monitoring of active network equipment. A relatend role is that of the network specialist or network analyst.

Database administrator

A database administrator (DBA) is responsible for the performance, intergrity and security of a database. The role of a database administrator has changed according to the technology of database management systems (DBMSs) as well as the needs of the owners of the database. A DBA may be tasked to perform database design, although those duties traditionally are duties of a database analyst or database designer.

System Analyst

A systems analyst designs new IT solutions to improve business efficiency and productivity. The work might be for an external client or an internal client (such as a department within the same organisation). Working closely with the client, analysts examine existing business models and flows of data, discuss their finding with the client, and design an appropriate improves IT solution. They produce outline designs and costings of new IT systems, specifying the operations the systems will perform, and the way data will be viewed by the user, present their design to the client and, once it is approved, work closely with the client team to implement the solution.

Programmer

A programmer is someone who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be know as a programmer analyst. A programmer's primary computer language (Lisp, Java, Delphi, C++, etc.) is often prefixed to the above titles, and those who work in a web enviroment often prefix their titles with web.