31 December 2011

Elements of an Information System


To be valuable, information must be accurate, organized, timely, accessible, useful, and cost-effective to produce. Generating information from a computer requires the following five elements:
  • Hardware
  • Software
  • Data
  • People
  • Procedures

Together, these elements (hardware, software, data, people, and procedures) comprise an information system.
 The hardware must be reliable and capable of handling the expected workload. The software must be developed carefully and tested thoroughly. The data entered into the computer must be accurate.
 Most companies with mid-sized and large computers have an IT (information technology) department. Staff in the IT department should be skilled and up-to-date on the latest technology. IT staff also should train users so that they understand how to use the computer properly. Today's users also work closely with IT staff in the development of computer applications that relate to their areas of work.
 Finally, all the IT applications should have readily available documented procedures that address operating the computer and using its programs.

24 December 2011

Embedded Computers


An embedded computer is a special-purpose computer that functions as a component in a larger product. Embedded computers are everywhere – at home, in your car, and at work. The following list identifies a variety of everyday products that contain embedded computers.
  • Consumer Electronics: mobile and digital telephones, digital televisions, cameras, video recorders, DVD players and recorders, answering machines
  • Home Automation Devices: thermostats, sprinkling systems, security monitoring systems, appliances, lights
  • Automobiles: antilock brakes, engine control modules, airbag controller, cruise control
  • Process Controllers and Robotics: remote monitoring systems, power monitors, machine controllers, medical devices
  • Computer Devices and Office Machines: keyboards, printers, fax, and copy machines

 Because embedded computers are components in larger products, they usually are small and have limited hardware. These computers perform various functions depending on the requirements of the product in which they reside. Embedded computers in printers, for example, monitor the amount of paper in the tray, check the ink or toner level, signal if a paper jam has occurred, and so on.

17 December 2011

Supercomputers


A supercomputer is the fastest, most powerful computer – and the most expensive. The fastest supercomputers are capable of processing more than one quadrillion instructions in a single second. With weights that exceeds 100 tons, these computers can store more than 20,000 times the data and information of an average desktop computer.
 Applications requiring complex, sophisticated mathematical calculations use supercomputers. Large-scale simulations and applications in medicine, aerospace, automotive design, online banking, weather forecasting, nuclear energy research, and petroleum exploration use a supercomputer.

10 December 2011

Mainframes


A mainframe is a large, expensive, powerful computer that can handle hundreds or thousands of connected users simultaneously. Mainframes store tremendous amounts of data, instructions, and information. Most major corporations use mainframes for business activities. With mainframes, enterprises are able to bill millions of customers, prepare payroll for thousands of employees, and manage thousands of items in inventory. On study reported that mainframes process more than 83 percent of transactions around the world.
 Mainframes also can act as servers in a network environment. Servers and other mainframes can access data and information from a mainframe. People also can access programs on the mainframe using terminals or personal computers.

03 December 2011

Servers


A server controls access to the hardware, software, and other resources on a network and provides a centralized storage area for programs, data, and information. Servers can support from two to several thousand connected computer at the same time.
 In many cases, one server accesses data, information, and programs on another server. In other cases, people use personal computers or terminals to access data, information, and programs on a server. A terminal is a device with a monitor, keyboard, and memory.

26 November 2011

Game Consoles


A game console is a mobile computing device designed for single-player or multiplayer video games. Standard game consoles use a handheld controller(s) as an Input device(s); a television screen as an output device; and hard disks, optical discs, and/or memory cards for storage. Weighing on average between two and nine pounds, the compact size of game consoles makes them easy to use at home, in the car, in a hotel, or any location that has an electrical outlet. Three popular models are Microsoft's Xbox 360, Nintendo's Wii and Sony's PlayStation 3.
 A handheld game console is small enough to fit in one hand, making it more portable than the standard game console. With the handheld game console, the controls, screen, and speakers are built into the device. Because of their reduced size, the screens are small – three to four inches. Some models use cartridges to store games; others use a memory card or a miniature optical disc. Many handheld game consoles can communicate wirelessly with other similar consoles for multiplayer gaming. Two popular models are Nintendo DS Lite and Sony's PlayStation Portable (PSP).
 In addition to gaming, many game console models allow users to listen to music, watch movies, keep fit, and connect to the Internet. Game consoles can cost from a couple hundred dollars to more than $ 500.

19 November 2011

Mobile Computers and Mobile Devices


A mobile computer is a personal computer that you can carry from place to place. Similarly, a mobile device is a computing device small enough to hold in your hand.
 The most popular type of mobile computer is the notebook computer. The following sections discuss the notebook computer and widely used mobile devices.

Notebook Computers
 A notebook computer, also called a laptop computer, is a portable, personal computer often designed to fit on your lap. Notebook computers are thin and lightweight, yet they can be as powerful as the average desktop computer. A netbook, which is a type of notebook computer, is smaller, lighter, and often not as powerful as a traditional notebook computer. Most netbooks cost less than traditional notebook computers, usually only a few hundred dollars. An ultra-thin is another type of notebook computers have touch screens, allowing you to interact with the device by touching the screen, usually with the tip of a finger.
 On  a typical notebook computer, the keyboard is on top of the system unit, and the monitor attaches to the system unit with hinges. These computers weigh on average from 2.5 to more than10 pounds (depending on configuration), which allows users to transport the computers from place to place. Most notebook computer can operate on batteries or a power supply or both.

Tablet PCs  Resembling a letter-sized slate, the Tablet PC is a special type of notebook computer that allows you to write or draw on the screen using digital pen.
With a digital pen, users write or draw by pressing the pen on the screen, and issue instructions to the Tablet PC by tapping on the screen. For users who prefer typing instead of handwriting, some Tablet PC designs have an attached keyboard; others allow you yo connect a separate keyboard to the device. Most Tablet PCs have touch screens. Tablet PCs are useful especially for taking notes in lectures, at meetings, conferences, and other forums where the standard notebook computer is not practical.

Mobile Devices
 Mobile devices, which are small enough to carry in a pocket, usually do not have disk drives. Instead, these devices store programs and data permanently on special memory inside the system unit or on small storage media such as memory cards. You often can connect a mobile device to a personal computer to exchange information between the computer and the mobile device.
 Some mobile devices are Internet-enabled, meaning they can connect to the Internet wirelessly. With an Internet-enabled device, users can chat, send e-mail and instant messages, and access the Web. Because of their reduced size, the screens on mobile devices are small, but usually are in color.
 Five popular types of mobile devices are smart phones, PDAs, handheld computers, portable media players, and digital cameras.

Smart Phones  Offering the convenience of one-handed operation, a smart phone is an Internet-enabled phone that usually also provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad. In addition to basic phone capabilities, a smart phone allows you to send and receive e-mail messages and access the Web – usually for an additional fee. Some smart phones communicate wirelessly with other devices or computers. Many also function as a portable media player and include built-in digital cameras so that you can share photos or videos with others as soon as you capture the image.
Many smart phones also offer a variety of application software such as word processing, spreadsheet, and games, and the capability of conducting live video conferences.
 Many smart phones have keypads that contain both numbers and letters so that you can use the same keypad to dial phone numbers and enter messages. Others have a built-in mini keyboard on the front of the phone or a keyboard that slides in and out from behind the phone.
Some have touch screens, where you press objects on the screen to make selections and enter text through an on-screen keyboard.
 Instead of calling someone's smart phone or cell phone, users often send messages to others by pressing buttons on their phone's keypad, keys on the mini keyboard, or images on an on-screen keyboard. Types of messages users send with smart phones include text messages, instant messages, picture messages, and video messages.
  • A text message is a short note, typically fewer than 300 characters, sent to or from a smart phone or other mobile device.
  • An instant message is a real-time Internet communication, where you exchange messages with other connected users.
  • A picture message is a photo or other image, sometimes along with sound and text, sent to or from a smart phone or other mobile device. A phone that can send picture messages often is called a camera phone.
  • A video message is a short video clip, usually about 30 seconds, sent to or from a smart phone or other mobile device. A phone that can send video messages often is called a video phone.
PDAs  A PDA (personal digital assistant) provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad. Most PDAs also offer a variety of other application software such as word processing, spreadsheet, personal finance, and games.
 A common input device for a PDA is a stylus. Some PDAs have a built-in miniature keyboard or an on-screen keyboard. Some PDAs also support voice input, have built-in cameras, and can function as a portable media player.
 Many PDAs are Internet-enabled so that users can check e-mail and access the Web.
Some also provide phone capabilities. As smart phones and PDAs continue a trend of convergence, it is becoming increasingly difficult to differentiate between the two devices. This has led some manufacturers to refer to PDAs and smart phones simply as handhelds.

Handheld Computers  A handheld computer, sometimes referred to as an Ultra-Mobile PC (UMPC), is a computer small enough to fit in one hand. Many handheld computers communicate wirelessly with other devices or computers and also include a digital pen or stylus for input.
 Some handheld computers have miniature or specialized keyboards. Many handheld computers are industry-specific and serve the needs of mobile employees, such as meter readers and parcel delivery people, whose jobs require them to move from place to place.

Portable Media Players  A portable media player is a mobile device on which you can store, organize, and play digital media. For example, you can listen to music; watch videos, movies, and television shows; and view photos on the device's screen. With most, you download the digital media from a computer to the portable media player or to media that you insert in the device.
 Some portable media players are Internet-enabled so that you can access Web sites and send e-mail messages directly from the device. Many offer personal information management functions such as a calendar and address book, and include a variety of games and other application software.
 Portable media players usually include a set of earbuds, which are small speakers that rest inside each ear canal. Some portable media players have a touch screen, while others have a touch-sensitive pad that you operate with a thumb or finger, to navigate through digital media, adjust volume, and customize settings.

Digital Cameras  A digital camera is a device that allows users to take pictures and store the photographed images digitally, instead of on traditional film. While many digital cameras look like a traditional camera, some are built into smart phones and other mobile devices.
 Although digital cameras usually have some amount of internal storage media such as memory cards. Digital cameras typically allow users to review, and sometimes modify, images while they are in the camera. Some digital cameras connect to or communicate wirelessly with a computer or printer, allowing users to print or view images directly from the printer. Some memory cards can connect to a network wirelessly, so that you can transfer photos directly from the memory card in the card in the camera to the Internet without requiring a computer.
 Often users prefer to download images from the digital camera to the computer. Or, you can remove the storage media such as a memory card from the digital camera and insert it in a card reader in or attached to the computer