O---LEVEL INFORMATION AND COMPUTER STUDIES BY. MWL. JAPHET MASATU.

Essential Introduction to Computers

1. Define the term computer and discuss the four basic computer operations: input, processing, output, and storage
2. Define data and information
3. Explain the principle components of the computer and their use
4. Describe the use and handling of floppy disks and hard disks
5. Discuss computer software and explain the difference between system software and application software
6. Identify several types of personal computer application software
7. Discuss computer communications channels and equipment and the Internet and World Wide Web
8. Explain how to purchase, install, and maintain a personal computer, a notebook computer, and a handheld computer
9. Define e-commerce

1. Computer: Input, Processing, Output, and Storage
In today's world, computers are used for almost every task imaginable. Routine activities such as paying bills, buying groceries, or communicating with a friend can be done with a computer. That is why it is important not only to know how to use a computer, but also to understand the components of a computer and what they do.
Recent studies report that almost 40% of homes surveyed have personal computers, and this number is growing. Given the widespread use of computers, computer literacy - a knowledge and understanding of computers and computer uses - has become an essential ingredient in the recipe for success in today's world. Florida was the first state to demand computer literacy of all students by grade 12.
Collectively, the electric, electronic, and mechanical equipment that makes up a personal computer is called hardware. Devices that surround the system unit (i.e., the keyboard, mouse, speakers, monitor, and so on) sometimes are known as peripheral devices.
Computers manipulate (process) data (input) to produce information (output) and hold (store) that information for future use. These operations are completed incredibly quickly. Today's supercomputer can perform 1.8 trillion operations per second. If a person did one arithmetic operation a second without stopping, it would take more than 31,000 years to perform the number of operations a supercomputer can do in one second.
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2. Data and Information
A major part of understanding computers is to know what goes into them (data), what comes out of them (information), and to understand the process of turning data into information, also known as the information processing cycle.
Understanding the difference between data and information is important. Clifford Stoll - lecturer, computer security expert, and author (The Cuckoo's Egg: Tracking a Spy Through the Maze of Computer Espionage and Silicon Snake Oil: Second Thoughts on the Information Superhighway are two of his most popular works) - notes a wide gap between data and information. Information has a pedigree, or lineage. Its source is known, whether a respected professor or a seventh grader. "The Internet has great gobs of data," Stoll maintains, "and little, little information."
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3. Components of the Computer and Their Use
A computer consists of five primary hardware components: input devices, the central processing unit (CPU), memory, output devices, and storage devices. These components work together with software to perform calculations, organize data, and communicate with other computers.
Different types of input devices transmit different types of data or transmit data in different ways. A keyboard is used to transmit alpha/numeric data by typing. In addition to the standard keys in the typing area, an enhanced keyboard contains:

• function keys that can be programmed to perform specific tasks
• status lights that indicate modes that can be turned on and off by toggle keys (e.g., caps lock and num lock)
• a numeric keypad that allows for rapid entry of numbers
• arrow keys and other cursor-control keys (e.g., home, end, page up, and page down) that control the on-screen movement of the insertion point
• special keys such as esc, shift, ctrl, and alt that have varying functions depending on the software

The mouse, like a trackball or joystick, is called a pointing device because it controls the movement of a pointer, or mouse pointer, on the computer screen. The first mouse was a one-button, rectangle shaped device invented by Doug Engelbart in 1964. A mouse is very easy to use. It requires empty desk space, however, and forces the user to remove a hand from the keyboard to give a command.
Different CPUs function at different speeds. The rate at which computer operations take place is measured in megahertz (MHz), or millions of electronic pulses per second. This rate varies among computers and should be a consideration when purchasing a personal computer. Computers have two basic types of memory. RAM (random access memory) is volatile, meaning that its contents are lost when the computer is turned off. ROM (read-only memory) is nonvolatile because it retains its contents even when the power is turned off. ROM stores information that does not change, such as the instructions and data used to start the computer when it is first turned on.
Like input devices, different types of output devices convey different types of information or convey information in different ways. Printer output sometimes is called hard copy because of its physical, touchable character. Monitor output, on the other hand, is called soft copy because it has only an electronic, intangible existence. Non-impact printers represent the fastest growing segment of the printer market. The drops of ink that form an ink-jet printer character are similar to the dots that form a dot matrix character figure, but there are many more of them. Good quality paper must be used with ink-jet printers so that the ink does not bleed. The speed quoted for impact printers often is measured in characters per second (cps). Like ink-jet printers, laser printer speed is measured in pages per minute (ppm). Although they are fast, all printers are much slower than computers. Because of this, most printers have a buffer that temporarily stores a few pages, allowing the computer to dump output into the buffer and continue processing. The most widely used PC monitors are 14- or 17-inch (measured from one corner to the diagonally opposite corner). With the growing popularity of portable computers, the clarity of LCD displays continues to improve. The quality of a monitor's display depends largely on three factors:

• resolution - the number of pixels displayed
• dot pitch - the distance between pixels
• refresh rate - the speed with which images are redrawn on the screen

Storage devices are different from memory. Memory, sometimes called primary storage, is fast, short-term, volatile, and relatively expensive. Storage devices, on the other hand, are slower, long-term, nonvolatile, and less expensive.
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4. Floppy Disks and Hard Disks
The data and information used in a computer needs to be stored for future use. The memory of a computer only holds items temporarily while they are being processed. When not being processed, these items must be stored in auxiliary storage devices. These devices include floppy disks, hard disks, CD-ROM, and DVD-ROM. When selecting a storage device it is important to know that each device holds different amounts of information.
Although floppy disks once were available in two sizes, the 5.25-inch floppy disk rarely is used today, and some believe it is destined for the same fate as the eight-track tape. Because of its rigid plastic shell, it may be difficult to see the 3.5-inch disk as "floppy." The name is justified, however, not only by the disk's ancestry but also by the flexible character of the disk itself. When a floppy disk drive is reading from or writing to a floppy disk, a light turns on next to the drive. Floppy disks never should be inserted into or removed from the drive when this light is on. Most magnetic disks are read/write storage media. Some optical discs, such as CD-ROMs, usually can be read from but not written to. Each track on a formatted floppy disk is very narrow. To see how narrow, try to draw 80 lines in a 11/4-inch space (the approximate radius of the floppy disk surface). Floppy disks are soft-sectored, meaning that the number of sectors is not predetermined. Floppy disk access time depends on the time needed to locate the correct track, the time required to rotate the disk to the proper sector, and the time necessary to transfer the data into main memory.
Although personal computer hard disks usually are fixed (i.e., not removable), some portable computers have removable hard disk drives. Unlike floppy disks, hard disks constantly are spinning, at a rate 10 to 20 times faster than floppy disks. Therefore, access time for hard disks is significantly less than access time for floppy disks. While a floppy disk read/write head rests on the disk, the read/write head for a hard disk hovers about 10 millionths of an inch above the disk surface. Contamination on the disk - a speck of dust (about 1550 millionths of an inch), a fingerprint (about 600 millionths of an inch), or a particle of smoke (about 250 millionths of an inch) - can cause a "head crash," destroying data and rendering the disk drive unusable. For this reason, hard disk drives are sealed and manufactured in an environment that typically is cleaner than a hospital operating room. Storage capacity can be increased on both hard disks and floppy disks with compression programs such as Stacker, WinZip, or PKZIP.
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5. Computer Software: System Software and Application Software
There are two categories of computer software: system software and application software. System software serves as the interface between a user and the computer's hardware. An example of system software would be an operating system such as Microsoft Windows. Application software consists of programs designed to perform specific tasks. An example of application software would be a spreadsheet program, such as Microsoft Excel.
A 3.5-inch floppy disk is computer hardware, but the programs stored on it are computer software. Although there are two types of software, system software and application software are designed to work hand-in-glove; that is, application software packages are designed to work with specific kinds of system software. By telling the computer how to perform common functions, the operating system frees application software to concentrate on producing information. Popular operating systems include Windows, the Mac OS, OS/2, UNIX, Linux, DOS, and NetWare. Operating systems that have a graphical user interface (GUI) often are called user-friendly. Studies have found that GUI users generally complete tasks more accurately, work faster, are more productive, and feel less fatigue.
To understand the relationship between application software and system software, draw four concentric circles. Label the innermost circle CPU, the next operating system, the next application software, and the last user. The resultant diagram illustrates how the operating system helps to insulate the user and application program from computer hardware.
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6. Types of Personal Computer Application Software
Many types of application software are available. The more popular application software includes word processing software, electronic spreadsheet software, database software, presentation graphics software, communications software, and electronic mail software. Knowing the function of each type of application software is one of the most important ingredients of being computer literate.
Several years ago, a survey of large and small businesses showed that the most often used applications were:

• Word processing and spreadsheet (used by 100% of those surveyed)
• Communications, electronic mail, database, and presentation graphics (used by about 95%)
• Desktop publishing (used by about 85%)
• Project management (used by about 70%)
• Personal information management (used by about 50%)

In word processing, any work developed through the writing process is a document. Word processing software makes it easier to create, edit, format, and print documents. Many word processing packages include a spell checker, grammar checker, and thesaurus.
The first spreadsheet software, VisiCalc, was introduced in 1979. By immediately displaying the results of changes, electronic spreadsheet packages provide a capability called what-if analysis. Another powerful capability, called goal-seek, finds what value is needed to reach a specified goal.
A database file is a collection of related data called records, each of which consists of a group of related facts called fields. The data can be manipulated, or a report, called a query, can be created based on user-specified criteria. Although most spreadsheet packages can manage data tables of a few thousand records, database software can efficiently handle much larger data tables.
Word processing and spreadsheet software came out around 1980. Presentation graphics software was not introduced until the mid to late 1980s. Nevertheless, it can be argued that presentation graphics software has had almost as great an impact on business, and on how people do business, as either of the older applications. Presentation graphics packages include libraries of clip art that can be inserted into slides and a slide sorter that can be used to organize the order effectively in which slides are presented.
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7. Computer Communications Channels and Equipment and the Internet and World Wide Web
Communicating with a computer is becoming the standard today for both business and personal use. The communications channels are constantly being upgraded in order to send information faster. Communications technologies have changed the way people interact through the use of e-mail, videoconferencing, and the Internet.
Many vendors sell network versions of their software. The network version resides on the network server and can be accessed by each computer on the network. When a network version is purchased, a site license is obtained from the vendor. The fee for the site license, usually based on the number of computers on the network, is less than the purchase of individual packages for each computer.
The number of people using the Internet is growing by 5% each month. Paul Moritz, a vice president at Microsoft, maintains that, "In the long run, it's hard to exaggerate the importance of the Internet." The Web, an innovation of Tim Berners-Lee, debuted in 1989. Since then, the Web has experienced astounding growth. Some experts claim that the size of the Web doubles every 60 days. Using links to move from one document to another often is called surfing the Web. Two popular Web browsers are Netscape Navigator and Microsoft Internet Explorer.
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8. How to Purchase, Install, and Maintain a Computer
At some point in your life, you will probably decide to purchase a computer. Aside from understanding the components discussed earlier, it also is important to be able to find the computer that best fits your needs. For example, most new computers come with application software already installed. If you do not use this software, then it is of no value even though you got it for "free." There are several things to look for when purchasing a new computer. If possible, speak to someone who is familiar with the purchasing process and can guide you along.
For most people, buying a computer is an expensive experience. Despite this, many people are woefully uninformed when they set out to purchase a computer. Although desktop computer systems remain popular, since 1993 sales of laptop, notebook, and smaller computers have rivaled sales of larger systems, partly because of their enhanced capabilities and increased use by field sales forces. Be careful when setting up a computer system. Failure to follow health guidelines can lead to painful, and even permanent, disabilities. Government studies indicate repetitive stress disorder (RSI) and cumulative trauma disorder (CTD), the most commonly reported problems associated with prolonged keyboard use, are responsible for half of work-related illnesses. Computer security is an increasingly important issue. A survey of American companies with more than 200 personal computers showed that over 60% had suffered at least one virus attack. Two of the major sources of viruses, free software and illegally copied software, more commonly are used by small companies and private individuals, so the percentage of PC users affected by viruses may be much higher. E-mail attachments have been the carriers of several recent virus attacks that have infected both business and home computer users.
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9. E-Commerce
Conducting business online is known as electronic commerce, or e-commerce, and includes such commercial activities as shopping and investing. The three types of e-commerce that exist today are business to consumer (B2C), consumer to consumer (C2C), and business to business (B2B).
If you have access to a computer, an Internet connection, and a means to pay for products or services, you can participate in e-commerce. Today, users can participate in e-commerce not only through desktop computers, but also through mobile devices such as laptop and handheld computers, pagers, and cellular phones. M-commerce (mobile commerce) is the term some people use to describe e-commerce activities that take place using mobile devices.
The more popular uses of e-commerce include shopping and investing. On the Web, you can buy and sell stocks, order flowers, purchase groceries and airline tickets, and even buy a car!
Three types of e-commerce exist: business to consumer (B2C), consumer to consumer (C2C), and business to business (B2B). Of the three, most e-commerce takes place between businesses, making B2B e-commerce transactions the most common.