Tools for an Information Age
*List some common input, output, and storage media.
*Distinguish data from information.
*Describe the significance of networking.
*Explain the significance of the internet.
*Explain the various classifications of computers.
Computer Literacy: 3 components
Note that no where in this definition suggests that you must be able to create the instructions that tell a computer what to do. So you don't need to program computers to be computer literate.
Ask yourself: Do you use a computer every day?
3 Fundamental Characteristic of Computers
*Speed: computers provide the processing speed essential for our fast-paced society. E.g., bank withdrawals, stock quotes, telephone calls, travel reservations, etc...
*Reliability: Computers are extremely reliable. Most errors supposedly made by computers are really human errors.
*Storage capability: Computer systems can store tremendous amounts of data, which can be located and retrieved efficiently.
Where Computers are Used (Everywhere!)
3 Main Components of a Computer System:
The equipment associated with a computer system is called hardware. This includes the system unit, monitor, keyboard, printers, ...
Software is also referred to as programs. A program is a set of instructions that tell the computer what to do. While the software provides the instructions for completing a task, the hardware actually does the work. Hardware is tangible (you can touch it). Software is not tangible.
People are the most important component people use the power of the computer for some purpose.
Input devices: accept data or commands in a form that the computer can use. For example: keyboard, mouse, scanner, bar code reader.
Ask yourself: What are some other input devices?
Processor: manipulates input data into the information people want. It executes the compute instructions.
Output devices: show people the processed data in understandable and usable form. For example: the monitor and printer.
Storage: consists of hard disks and diskettes and other media. Also called secondary storage. Long term use.
RAM Memory: holds data and programs only temporarily. It can hold data only temporarily because it requires a continuous flow of electric current; if the current is interrupted, the data is lost.
Ask yourself: Is this like the human mental process?
Magnetic disk: uses a magnetic disk drive to read and write data. Examples are the floppy disk, Zip disk, and hard disk.
Optical disk: uses a laser beam (optical disk drive). Examples are CD's and DVD's.
Magnetic tape: usually comes on a cartridge and is similar to a tape from a tape recorder. Uses a tape drive. Tape is usually used for backup purposes. It is inexpensive but it is very slow.
A Computer System Requires
A computer is a machine that can be programmed to accept data (input), process it into useful information (output), and store it away (in a secondary storage device) for safekeeping or later use. These 4 primary components (functions) are the IPOS cycle.
The IPOS cycle is directed by software instructions but performed by the hardware.
Ask yourself: Is the IPOS cycle like the human mental process?
Data vs. Information
- Raw facts
Data is provided to the computer as input.
Information is provided to the user as output.
The CPU transforms data into information.
Networks allow sharing of resources and provide communications between computers.
Resources: printers, hard disks, software, and data.
Users who connect their computers via the phone lines must use a hardware device called a modem to reconcile the inherent differences between computers and the phone system.
LAN: personal computers in an office (located close together) are connected.
WAN: computers in a large geographical area such as an entire college campus, a city, a state or across the globe are connected.
Ask yourself: Where else could you use a network?
The internet is the largest network system. It is not really a single network but a loosely organized collection of thousands of networks.
TCP/IP: Transmission Control Protocol/Internet Protocol is a standard that allows different types of computers to communicate with one another.
No one owns the internet. It has no central headquarters. There is no comprehensive index of what information is available.
Other services of the internet: E-mail, ftp, chat, telephony.
Ask yourself: Is unregulated worldwide connectivity good?
Ask yourself: Can the government do that? Carnivore is an FBI system that can read email, web pages, and other internet data from selected individuals.
More About the Internet
ISP: A users computer must connect to a type of computer called a server. The supplier of the server computer, ISP, charges a fee, usually monthly, that either covers unlimited access or is based on the amount of service provided.
WWW: World Wide Web. Not the same as the Internet. WWW is a subset of text, images, and sounds linked together. Users can "browse" through information on the Web using software called a Web browser.
Web site: a collection of related web pages
Home Page: main page of a web site.
Classification of Computers
Personal computers, known as PCs, are desktop computers. Workstations are small enough to fit on a desktop but approach the power of a mainframe.
A net computer (or network appliance) is a limited use computer with a CPU and minimal memory, offered with internet access in mind (e.g., WebTV). Most net computers have no disk storage at all.
Notebook computers are lightweight (under 6 pounds) and portable. Somewhat larger and heavier versions of these computers are known as laptops and can be used as desktop replacements.
Handheld computers: personal digital assistant (PDA) is also called pen based computer. Pocket PC has slightly more power than a PDA, and can run stripped down software like word processing and spreadsheets.
Mainframes: capable of processing data at very high speeds billions of instructions per second. The price of these systems can go up to many millions of dollars. Their principal use is for processing vast amounts of data quickly, so some of the obvious customers are banks, insurance companies. These computers are designed for multiple users. Mainframes are also used as servers.
Supercomputers: are the mightiest, most expensive, and the fastest computers. They can process trillions of instructions per second. Their uses include special effects for movies, worldwide weather forecasting, and weapons research.
Ask yourself: Which computer could be more useful for you?