What is Computer ?
A computer is an electronic device – a flexible machine that can manipulate data. Computer is being used for tasks as adding up the supermarket bill, getting cash at an ATM, computers are also used by writers, television producers, musicians, poets, graphics illustrators and scholars of medieval history. A computer is programmable i.e. the computer depends totally on the program, which the computer is using. (A program is a list of instructions, telling the computer ‘what to do.’) A computer’s hardware (the machine and its components) is designed to be as flexible
as possible. By using computer programs, called software, one transforms this flexible hardware into a tool for a specific purpose.
- Input: A computer accepts data that is provided by means of an input device, such as a keyboard.
- Processing: A computer performs operations on the data to transform it in some way.
- Output: A computer produces output on a device, such as a printer or a monitor, that shows
the results of processing operations.
- Storage: A computer stores the results of processing operations for future use.
This definition is often referred to as the IPOS cycle. The four steps of the IPOS cycle-input, processing,
output, storage – do not have to occur in a rigid IPOS sequence. Under the direction of a program, a
computer uses the steps of this process when needed and as often as needed. The use of a personal
computer, a computer designed to meet an individual’s computing needs, illustrates these four
basic computer operations. We use the keyboard for taking the input data. The computer’s internal
circuitry processes the data. We see the results (output) on the computer’s monitor (the TV-like
display) and we can print these results on the printer. We can also store the results on the computer’s
internal disk or on a removable disk.
What is computer
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The system unit contains the components with which the computer processes and stores data. The
keyboard and the mouse are input devices. The monitor displays the output. The printer prints
USES OF COMPUTER :-
The purpose of the computer is to transform data into information. In this context, data means some
kind of unorganized material that can be entered into the computer – a rough sketch that needs work,
a first draft of an essay that needs revision or polishing, figures from a company’s books, a list of
names and addresses. What results from processing operations is information, i.e. data that has
been made meaningful and useful. This capability to process data can be used in a variety of ways.
People have come up with some very interesting uses.
A psychologist keeps a computer in the counselling room. At the touch of a key, the psychologist
can search through references on a computer disk for information relating to topics that come up
during counselling sessions.
ELEMENTS OF THE COMPUTING PROCESS
Computers consist of hardware, the physical parts of the computer and software, the programs that
tell the computer ‘what to do.’ Processing data into information (the computing process) involves
more elements than just hardware and software. All these elements must be organized so that each
works smoothly and efficiently with the others. In the computing process, computers integrate the
use of five key elements which are given as follows:
The computing process, in short, includes everything and everyone necessary for the computer to
perform a useful task. The following sections show that ‘how each of these elements works in the
1. Hardware :-
Hardware refers to the physical parts of the computer. Computer hardware is versatile-but it
does depend on the computer program, we use. The key to the computer’s versatility is memory. One
can think of memory as a temporary workspace. The computer’s processor uses this workspace as a
scratch pad during processing. Many people confuse memory with storage. Memory is temporary.
When we turn off the computer, everything in the memory is lost. Storage is usually permanent.
On most computers, storage also has far greater capacity than memory.
Understanding the distinction between memory and storage is essential. Some programs keep their
output in memory. One must transfer this information to a storage device, such as a disk drive, if
one wants to keep the information permanently. If we switch off the computer without saving this
information (transferring it to storage), the information is lost.
2. Software :-
Software is the set of instructions (also called a program) that guides the hardware through its job.
The following sections explore additional aspects of software.
(a) Programming Languages: Software programs must be written in programming languages. Programmers i.e. people trained in the use of a programming language, write programs.
(b) System and Application Software Packages: Today’s complex computer programs, such as Microsoft Word (a word processing program), consist of many separate programs that are designed to run together. In recognition of this fact, people sometimes speak of software packages. When we buy Microsoft Word, we are actually buying a software package rather than a single program. Based on the function of the package, software packages are divided into two categories: system software and application software. Computer literacy involves; learning that ‘how to use both system software and one or more application programs’. Computers need system software to function. System software integrates the computer’s hardware components and provides tools for day-to-day maintenance tasks, such as displaying a list of the files contained on a disk. MS-DOS, UNIX, Microsoft Windows 98 and System 7 are well-known examples of system software.
(c) Application software: It turns the computer into a tool for a specific task, such as writing. Not all application programs will be useful to us. Some application programs are special-purpose programs, which perform a specific task for a single profession. For example, safety managers use a program that prints records of occupation-related injuries and illnesses in a format required by a government health bureau. If we aren’t a safety manager, we would not fi nd this application program interesting or useful. Other application programs are called general-purpose programs. People use these programs for a variety of tasks. Commonly used general-purpose programs
include the following:
- Word processing: More than 85 per cent of the personal computers are equipped with a word processing program, which transforms the computer into a tool for creating, editing, proofing, printing and storing text. Many of today’s books originated in text typed into computers-including this one also.
- Desktop publishing: In the past, newsletters and magazines were created through an expensive, tedious process called layout, in which someone does the job of cut and pasting photographs, borders and text to create a pleasing design. With the help of the desktop publishing software in the computer, we can produce attractive results with a little special training.
- Electronic spreadsheet: Businesses previously worked out budgets and made forecasts using accountant’s paper and a calculator. Electronic spreadsheet programs enable us to type the headings and numbers into a computerized version of accountant’s paper, but with a twist. We can hide formulae within the on-screen ‘paper.’ These formulae perform computations on the data. The payoff is that one can change any number and immediately see the effect of the change. People use electronic spreadsheets for many purposes, not just business-related ones. For example, a forest ranger uses an electronic spreadsheet to analyses data concerning endangered animal populations.
- Database: A database program creates an electronic version of a card fi le-and the program gives us the tools, needed to organize this fi le (for example, by alphabetizing it) and to retrieve information. An eighth-grade English teacher, for instance, could create a database of interesting uses of language – and retrieve examples for use in class discussions.
- Telecommunications software: These software transforms a computer into a terminal, which can connect to a multiuser computer system by means of the telephone. Commercial multiuser systems enable us to join discussion groups, exchange mail with other users, make plane and hotel reservations and obtain free software for our computer.
- Graphics software: Are we going to give a public presentation in our future? If so, we need to learn ‘how to use presentation of Graphics programs to create attractive charts and graphs that you can share with the audience.’
3. Data :-
Computers transform data into information. Data is the raw material; information is processed data. Data is the input to the processing; information is the output. A useful model to describe the relationship between data and information is called the systems model. It shows that data goes into a process and information is then output.
Several characteristics distinguish useful information from data. The purpose of information is to help people for making well-informed decisions, but what makes information useful? Information must be relevant, timely, accurate, concise and complete in order to be useful. Data must be accurate but doesn’t need to be relevant, timely or concise.
4. People :-
One may be surprised to learn that people are part of the computing process. Some computers, such as the computer chip that controls an automobile engine, function without human intervention. But even these computers were designed by people and occasionally require maintenance by people.
Most computers require people, who are called users (or sometimes end users). Some users progress beyond the basics of computer literacy. They learn the advanced features of application programs.
With this knowledge, these users can customize an application program for a specific task. These knowledgeable people are called power users.
Computer professionals have taken intermediate and advanced courses about computers. These people apply their professional training to improve the performance, case of use and efficiency of computer systems. One kind of computer professional is the programmer, who creates new computer programs. Excellent career opportunities exist for students interested in becoming computer professionals.
5. Procedures :-
Procedures are the steps that one must follow to accomplish a specific computer-related task. Part of a user’s computer literacy is, knowing common procedures. We already know several computer procedures. For example, we have probably used an Automated Teller Machine (ATM). Inside, the ATM is a computer. In response to the on-screen messages, called prompts, we insert our card, enter our Personal Identification Number (PIN) and tell the machine how much money we want.
CHARACTERISTICS OF COMPUTERS
No matter where computers are found or how they are applied, they’re used for input, processing, output and storage. But computers wouldn’t be worth the trouble without the following characteristics:
- Computers are fast. Many of today’s computers can perform hundreds of millions of processing operations in one second.
- Computers are reliable. Today’s computers may run day in and day out for years without failure.
- Computers are accurate. The computer’s physical processing circuits rarely make errors. Computers make errors, of course, but there are almost always due to faulty programs or incorrect data input.
- Computers can store massive amount of information. Today’s personal computers can be equipped with disks capable of storing more than forty billion characters (letters or numbers). That capacity is enough to store the complete works of William Shakespeare, an unabridged English dictionary, a 32-volume encyclopedia, a world atlas and almanac, dozens of computer Computer Fundamentals programs and all our written work from the third grade through graduate school with room for more.
- Computers can move information very quickly from one place to another. Using all experimental
connection that may soon play a role in the Information Superhighway, one computer can send
the entire text of the Encyclopedia Britannica to another linked computer in less than one
A computer-literate person knows that the computer is a tool for creating useful information that can be printed, communicated to others and stored for future use.
CLASSIFICATION OF COMPUTERS
The computer puting on the desk in the classroom is a microcomputer. It is a small, powerful piece of equipment. Even so, the power of the microcomputer is not enough for most large organizations. The computer industry consists of more than just microcomputers. Any classification of computers is somewhat arbitrary. Traditionally, computers have been classified by their size, processing speed and cost. This section explores four commonly used classifications:
- Workstations and Microcomputers
- Portable Computers
1. Supercomputers :- Supercomputers can be accessed by many individuals at the same time. Supercomputers are used primarily for scientific applications that are mathematically intensive. The aerospace, automotive, chemical, electronics and petroleum industries use supercomputers extensively. Supercomputers are used in weather forecasting and seismic analysis. These are found in many public and private research centers, such as universities and government laboratories. A supercomputer was used to alert scientists to the impending collision of a comet with Jupiter in 1994, giving them time to prepare to observe and record the event. The United States Department of Energy recently contracted with IBM for an ‘ultra-supercomputer,’ three hundred times faster than any existing machine. The ultra supercomputer will simulate nuclear explosions (eliminating the need to detonate any bombs), model global weather trends and design power plants. (what is computer).
Supercomputers derive much of their speed from the use of multiple processors. Multiprocessing enables the computers to perform tasks simultaneously-either assigning different tasks to each processing unit or dividing a complex task among several processing units. The first supercomputer had four central processing units; the massively parallel processors of today contain hundreds of processors
The speed of modern supercomputers is measured in nanoseconds and gigaflops. A nanosecond is one billionth of a second. A gigaflop is one billion floating-point arithmetic operations per second. Supercomputers can perform at up to 128 gigaflops and use bus widths of 32 or 64 bits. This capability makes supercomputers suitable for processor-intensive applications, such as graphics. Supercomputers are rarely used for input/output-intensive processing, such as accounting or record-keeping operations.
2. Mainframes :- For input/output-intensive operations, mainframe computers are much more suitable than supercomputers. Many modern mainframes have multiprocessing capabilities; however, these are generally limited to eight or fewer processors. The processors in mainframes are slower than those in supercomputers, with speed measured in megaflops (millions of floating-point arithmetic operations per second) rather than gigaflops. A mainframe computer system is usually composed of several computers in addition to the mainframe or host processor, The host processor is responsible for controlling the other processors, all the peripheral devices and the mathematics operations. A front-end processor is responsible for handling communications to and from all the remote terminals connected to the computer system. Sometimes a backend processor is used to handle data retrieval operations. Although the host computer could perform all these operations, it can be used more efficiently if relieved of time-consuming chores that do not require processing speed.
Mainframe computer systems are powerful enough to support several hundred users simultaneously at remote terminals. Terminals can be located near the computer or miles away. (what is computer) Computers can support hundreds of users by keeping numerous programs in primary memory and rapidly switching back and forth between programs. Because computers are so much faster than people, the users never notice that the computer is handling other tasks. This capability to process multiple programs concurrently for multiple users is known as multiprogramming.
3. Minicomputers :- The major difference between mainframes and minicomputers is in scale. Minicomputers can perform the same types of tasks as mainframes, but minicomputers are a little slower. Like mainframes,
minicomputers can accommodate remote users, but not as many. Minicomputers’ input, output and Computer Fundamentals storage devices look like those on mainframes; but minicomputers have slightly less storage and the
printers are slightly slower. The distinctions between these categories of computers are blurring as time passes. Minicomputers are frequently referred to as mid-range computers.
4. Workstations and Microcomputers :- When we are working on a multi-user computer, such as a mainframe or a minicomputer, we can control the input and see the output on the display, but we control nothing else. A single-user computer gives us control over all the phases of computer processing: input, processing, output and storage. We can select the programs we want to use and we don’t have to compete with other users to gain access to the system. A single-user system is designed to meet the computing needs of an individual. Single-user computers fall into two categories: workstations and microcomputers.
(a) Workstations: This is a powerful desktop computer designed to meet the computing needs of engineers, architects and other professionals who need detailed graphics displays. For example, workstations are commonly used for Computer-Aided Design (CAD), in which industrial designers create pictures of technical parts or assemblies. To process these complex and detailed diagrams, the computer needs much processing power and storage. Workstations are also frequently used as servers for local area networks.
The workstation has sometimes been called a ‘supermicro.’ The workstation looks very much like a desktop microcomputer, but the chips inside make the difference. Most workstations use Reduced Instruction Set Computer (RISC) microprocessors. Computer designers have discovered that by eliminating infrequently used pre programmed instructions, the speed of the processor can be increased. Many new processor chips, including the DEC Alpha and the PowerPC, are RISC chips. RISC processors are particularly useful in special-purpose applications, such as graphics, in which speed is critical. The DEC Alpha chip was the first microprocessor designed to work with a 64-bit bus.
(b) Microcomputers: The boundary between workstations and personal computers is becoming less distinct. Today’s best personal computers are more powerful and offer more precise displays than the workstations of the recent past. The new Pentium Pro microcomputers have multiprocessing capabilities. In addition, the distinction between workstations and minicomputers is becoming blurred because of the most powerful workstations. These
workstations can be equipped so that more than one person can use the workstation at once, in effect making the workstation a minicomputer.
Most microcomputers enable the user to switch between tasks. This capability is known as multitasking – a single user variation on multiprogramming. Multitasking can be a great timesaver. Suppose that we are using a word processor to write a test paper and we need to do some computations on the computer and use the results in the paper. Without multitasking, we would have to close the test paper file and the word processing application, open the calculator application, make the computations, write down the results, close the calculator application and reopen the word processing application and the test paper fi le. With multitasking, we simply open the calculator application, make the calculations and switch back to the test paper fi le. This capability to task-swap between the paper and the calculator saves time.
5. Portable Computers :- The first portable computers were dubbed ‘luggables’ and for good reason. They weighed as much as 28 pounds. Soon, reductions in size created the laptop computer. As many people discovered to their dismay, however, 10 pounds can seem like 20 if one must carry a laptop through a large airport or for any long distance.
Portable computing came of age with the creation of notebook computers, portable computers that are small
enough to fi t into an average-sized briefcase. At first, these computers were underpowered and didn’t offer
adequate storage. Today, new models offer as much processing power and storage as microcomputers and even some workstations. Notebooks have become very popular. Some people use notebooks instead of desktop computers.