Sunday, October 11, 2009

List of the System Unit

  • Expansion Card
An expansion card is a printed circuit board that can be installed in computer to add functionality to it. For example, a user may add a new graphics card to his computer to give it more 3D graphics processing power. An audio engineer may add a professional sound card to his machine to increase the computer's audio input and output connections. Users that need more Firewire or USB ports can add Firewire or USB expansion cards, which provide additional connections.




  • Network Interface Card (NIC)

An NIC (network interface card) is an expansion card that provides connectivity between a PC and a network such as a LAN, NICs are sometimes called ethernet adapters. Network Interface Cards (NICs) can be internal or external add-ons and come with various specifications, one of which is transfer rate although most modern network interface cards support up to 100Mbps, and the more expensive Gigabit ethernet cards supporting up to 1000Mbps.




  • 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. The user doesn't have to tell the computer. In many earlier computer systems, the user was required to explicitly tell the operating system when a new device had been added. Microsoft made Plug and Play a selling point for its Windows operating systems. A similar capability had long been built into Macintosh computers. With Microsoft's participation, Plug and Play has been replaced by an open, industry standard, Universal Plug and Play (UPnP), which uses Internet protocols for seamless device plug-in.





  • Sockets
Sockets is a method for communication between a client program and a server program in a network. A socket is defined as "the endpoint in a connection." Sockets are created and used with a set of programming requests or "function calls" sometimes called the sockets application programming interface (API). The most common sockets API is the Berkeley Unix C interface for sockets. Sockets can also be used for communication between processes within the same computer.





  • Chips
"Chip" is short for microchip, the incredibly complex yet tiny modules that store computer memory or provide logic circuitry for microprocessors. Perhaps the best known chips are the Pentiummicroprocessors from Intel. The PowerPC microprocessor, developed by Apple, Motorola, and IBM, is used in Macintosh personal computers and some workstations. AMD and Cyrix also make popular microprocessor chips. There are quite a few manufacturers of memory chips. Many special-purpose chips, known as application-specific integrated circuits, are being made today for automobiles, home appliances, telephones, and other devices.





  • Slots
In computers, a slot, or expansion slot , is an engineered technique for adding capability to a computer in the form of connection pinholes (typically, in the range of 16 to 64 closely-spaced holes) and a place to fit an expansion cardcontaining the circuitry that provides some specialized capability, such as video acceleration, sound, or disk drive control. Almost all desktop computers come with a set of expansion slots. These help ensure that you'll be able to add new hardware capabilities in the future.





  • Serial Port
Serial ports are a type of computer interface that complies with the RS-232 standard. They are 9-pin connectors that relay information, incoming or outgoing, one byte at a time. Each byte is broken up into a series of eight bits, hence the termserial port.





  • Universal Serial Bus Port
Short for Universal Serial Bus, an external bus standard that supports data transfer rates of 12 Mbps. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards. USB also supports Plug-and-Play installation and hot plugging.





  • 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. The FireWire port has been in common use since 1995, when Apple, Inc. first began to include the porton a number of digital camcorders. Today, the FireWire port is used on a number of other devices.




Monday, October 5, 2009

Input and Output

  • Magnetic ink character recognition (MICR)
  • Magnetic Ink Character Recognition, or MICR, is a special kind of optical character recognition technology or a technique for reading and processing data printed with ink that contains magnetic particles: used esp. in sorting bank checks automatically. MICR 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. The use of magnetic printing allows the characters to be read reliably even if they have been overprinted or obscured by other marks, such as cancellation stamps.

  • Optical-character recognition (OCR)




  • Optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the computer can manipulate (for example, into ASCII codes). 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. Most OCR systems use a combination of hardware (specialized circuit boards) and software to recognize characters, although some inexpensive systems do it entirely through software. Advanced OCR systems can read text in large variety of fonts, but they still have difficulty with handwritten text.
    The potential of OCR systems is enormous because they enable users to harness the power of computers to access printed documents. OCR is already being used widely in the legal profession, where searches that once required hours or days can now be accomplished in a few seconds.

  • Optical-mark recognition (OMR)
    Optical Mark Recognition or OMR is the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms. It is generally distinguished from OCR by the fact that a recognition engine is not required. This 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 are made on the form. 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, questionnaires and ballots.


  • Dot Matrix Printer

A dot matrix printer or impact matrix printer is a type of 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 typewriter. Unlike a typewriter or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.
Each dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate (often made of an artificial jewel such as sapphire or ruby) pierced with holes to serve as guides for the pins. The moving portion of the printer is called the print head, and when running the printer as a generic text device generally prints one line of text at a time. Most dot matrix printers have a single vertical line of dot-making equipment on their print heads; others have a few interleaved rows in order to improve dot density.

  • Plotters


  • 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. Pen plotters print by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Pen Plotters are often incapable of creating a solid region of color; but can hatch an area by drawing a number of close, regular lines. When computer memory was very expensive, and processor power was very limited, this was often the fastest way to produce color high-resolution vector-based artwork, or very large drawings efficiently.
    Traditionally, printers are primarily for printing text. This makes it fairly easy to control, simply sending the text to the printer is usually enough to generate a page of output.


  • Photo Printer


  • A photo printer is a printer (usually 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. Many inkjet printers currently sold to home users are marketed as "photo printers" because there are no official specifications designating what is and isn't a photo printer. Not all these models print photos as well as dedicated photo printers can, so some see this as a marketing ploy to increase the appeal of the product to the consumer.



  • Portable Printer

















  • Fax Machine
    Fax is a telecommunications technology used to transfer copies (facsimiles) of documents, especially using affordable devices operating over the telephone network. The word telefax, short for telefacsimile, for "make a copy at a distance", is also used as a synonym. Although fax is not an acronym, it is often written as “FAX”. The device is also known as a telecopier in certain industries. When sending documents to people at large distances, faxes have a distinct advantage over postal mail in that the delivery is nearly instantaneous, 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.



  • Multi-functional Devices

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 devices such as printer, scanner, photocopier, fax, e-mail.









  • Internet Telephones
  • Internet telephony refers to communications services — voice, facsimile, and/or voice-messaging applications — that are transported via the Internet, rather than the public switched telephone network (PSTN). The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and compression/translation of the signal into Internet protocol (IP) packets for transmission over the Internet; the process is reversed at the receiving end.



  • Telephony

In telecommunication, telephony encompasses the general use of equipment to provide voice communication over distances, specifically by connecting telephones to each other.
Digital telephony is the use of digital technology in the provision of telephone services and systems. Almost all telephone calls are provided this way, but sometimes the term is restricted to cases in which the last mile is digital, or where the conversion between digital and analog signals takes place inside the telephone. Telephony was digitized to cut the cost and improve the quality of voice services, but digital telephony was then found useful for new network services (ISDN) to transfer data speedily over telephone lines.
IP telephony is a modern form of telephony which uses the TCP/IP protocol popularized by the Internet to transmit digitized voice data. Contrast this with the operation of POTS (an acronym for "plain old telephone service").
Computer telephony integration (CTI) enables computers to know about and control phone functions such as making and receiving voice, fax, and data calls with telephone directory services and caller identification. The integration of telephone software and computer systems is a major development in the evolution of the automated office.





Monday, August 3, 2009

Careers in IT

The definition of:

*Webmaster

Webmaster is the person responsible for creating, managing, and maintaining one or more web-servers or websites. They also called a web architect, web developer, site author, website administrator, or webmeister. An alternative definition of webmaster is a businessperson who uses online media to sell products and/or services.




*Computer support specialist

Provide technical assistance and training to system users. Investigate and resolve computer software and hardware problems of users. Answer clients' inquiries in person and via telephone concerning the use of computer hardware and software, including printing, word processing, programming languages, electronic mail, and operating systems.




*Technical Writer

A technical writer is a professional writer who designs, writes, creates, maintains, and updates technical documentation—including online help, user guides, white papers, design specifications, system manuals, and other documents. Engineers, scientists, and other professionals may also produce technical writing, sometimes handing their work to a professional technical writer for editing and formatting. A technical writer produces technical documentation for technical, business, and consumer audiences.




*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. "Software engineer," "systems programmer" and "systems engineer" titles are often synonymous.




*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

An individual responsible for the design and management of the database and for the evaluation, selection and implementation of the database management system. 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

A system analyst is the person who selects and configures computer systems for an organization or business. His or her job typically begins with determining the intended purpose of the computers. This means the analyst must understand the general objectives of the business, as well as what each individual user's job requires. Once the system analyst has determined the general and specific needs of the business, he can choose appropriate systems that will help accomplish the goals of the business. The system analyst must have a solid understanding of computer hardware and software and should keep up-to-date on all the latest technologies.




*Programmer

Individual that composes instructions for computer systems to refer to when performing a given action. Programmers usually have an extensive background in some form of computer coding language, which may include XML, PHP, Perl, HTML, or SQL. Programmers are essential to the development of computers because without the coding that is necessary to make a computer work properly, the machine would be useless. Programmers may specialize in one area or may write instructions for a wide range of systems or programs.