HSEB Notes on Introduction and Evolution of Computer
Class : 11
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem. An important class of computer operations on some computing platforms is the accepting of input from human operators and the output of results formatted for human consumption. The interface between the computer and the human operator is known as the user interface.
Conventionally a computer consists of some form of memory, at least one element that carries out arithmetic and logic operations, and a sequencing and control unit that can change the order of operations based on the information that is stored. Peripheral devices allow information to be entered from an external source, and allow the results of operations to be sent out. A computer's processing unit executes series of instructions that make it read, manipulate and then store data. Conditional instructions change the sequence of instructions as a function of the current state of the machine or its environment.
The first electronic digital computers were developed in the mid-20th century (1940–1945). Originally, they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs). In this era mechanical analog computers were used for military applications. Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". However, the embedded computers found in many devices from mp3 players to fighter aircraft and from toys to industrial robots are the most numerous.
General Functions of Computer
Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations. A computer has four functions:
a. accepts data Input
b. processes data Processing
c. produces output Output
d. stores results Storage
Input (Data): Input is the raw information entered into a computer from the input devices. It is the collection of letters, numbers, images etc.
Process: Process is the operation of data as per given instruction. It is totally internal process of the computer system.
Output: Output is the processed data given by computer after data processing. Output is also called as Result. We can save these results in the storage devices for the future use.
Storage: Computer data storage, often called storage or memory, refers to computer components andrecording media that retain digital data. Data storage is a core function and fundamental component of computers.
Computer System
All of the components of a computer system can be summarized with the simple equations.
COMPUTER SYSTEM = HARDWARE + SOFTWARE+ USER
• Hardware = Internal Devices + Peripheral Devices
The hardware are the parts of the computer itself including the Central Processing Unit (CPU) and
related microchips and micro-circuitry, keyboards,monitors, case and drives (hard, CD, DVD, floppy, optical, tape, etc...). Other extra parts called peripheral components or devices include mouse, printers,modems, scanners, digital cameras and cards (sound, colour, video) etc... Together they are often referred to as a personal computer. All physical parts of the computer (or everything that we can touch) are known as Hardware.
• Software = Programs
The software is the information that the computer uses to get the job done. Software needs to be accessed before it can be used. There are many terms used for the process of accessing software including running, executing, starting up,opening, and others. Computer programs allow users to complete tasks. A program can also be referred to as an application and the two words are used interchangeably. Software gives "intelligence" to the computer.
• USER = Person, who operates computer.
A user is an agent, either a human agent (end-user) or software agent, who uses a computer or network service. Users are also widely characterized as the class of people that use a system without complete technical expertise required to understand the system fully. Such users are also divided into users and power users. Both are terms of degradation but the latter connotes a "know-it-all" attitude. In projects in which the actor of the system is another system or a software agent, it is quite possible that there is no enduser for the system. In this case, the end-users for the system would be indirect end-users.
CHARACTERISTICS OF COMPUTER
Speed, accuracy, diligence, storage capability and versatility are some of the key characteristics of a computer. A brief overview of these characteristics are :
Speed : The computer can process data very fast, at the rate of millions of instructions per second. Some calculations that would have taken hours and days to complete otherwise, can be completed in a few seconds using the computer. For example, calculation and generation of salary slips of thousands of employees of an organization, weather forecasting that requires analysis of a large amount of data related to temperature, pressure and humidity of various places, etc.
Accuracy : Computer provides a high degree of accuracy. For example, the computer can accurately
give the result of division of any two numbers up to 10 decimal places.
Diligence: When used for a longer period of time, the computer does not get tired or fatigued.
It can perform long and complex calculations with the same speed and accuracy from the start till
the end.
Storage : Capability Large volumes of data and information can be stored in the computer and also retrieved whenever required. A limited amount of data can be stored, temporarily, in the primary memory. Secondary storage devices like fl oppy disk and compact disk can store a large amount of data permanently.
Versatility : Computer is versatile in nature. It can perform different types of tasks with the same ease. At one moment you can use the computer to prepare a letter document and in the next moment you may play music or print a document.
Computers have several limitations too. Computer can only perform tasks that it has been programmed
to do. Computer cannot do any work without instructions from the user. It executes instructions as specifi
ed by the user and does not take its own decisions.
Application of Computers
Computers have proliferated into various areas of our lives. For a user, computer is a tool that provides the desired information, whenever needed. You may use computer to get information about the reservation of tickets (railways, airplanes and cinema halls), books in a library, medical history of a person, a place in a map, or the dictionary meaning of a word. The information may be presented to you in the form of text, images, video clips, etc. Some of the application areas of the computer are listed below:
Education : Computers are extensively used, as a tool and as an aid, for imparting education. Educators use computers to prepare notes and presentations of their lectures. Computers are used to develop computer-based training packages, to provide distance education using the e-learning software, and to conduct online examinations. Researchers use computers to get easy access to conference and journal details and to get global access to the research material.
Entertainment : Computers have had a major impact on the entertainment industry. The user can download and view movies, play games, chat, book tickets for cinema halls, use multimedia for making movies, incorporate visual and sound effects using computers, etc. The users can also listen to music, download and share music, create music using computers, etc.
Sports: A computer can be used to watch a game, view the scores, improve the game, play games (like chess, etc.) and create games. They are also used for the purposes of training players.
Advertising: Computer is a powerful advertising media. Advertisement can be displayed on different websites, electronic mails can be sent and reviews of a product by different customers can be posted. Computers are also used to create an advertisement using the visual and the sound effects. For the advertisers, computer is a medium via which the advertisements can be viewed globally. Web advertising has become a signifi cant factor in the marketing plans of almost all companies. In fact, the business model of Google is mainly dependent on web advertising for generating revenues.
Medicine : Medical researchers and practitioners use computers to access information about the advances in medical research or to take opinion of doctors globally. The medical history of patients is stored in the computers. Computers are also an integral part of various kinds of sophisticated medical equipments like ultrasound machine, CAT scan machine, MRI scan machine, etc. Computers also provide assistance to the medical surgeons during critical surgery operations like laparoscopic operations, etc.
Science and Engineering: Scientists and engineers use computers for performing complex scientifi c calculations, for designing and making drawings (CAD/CAM applications) and also for simulating and testing the designs. Computers are used for storing the complex data, performing complex calculations and for visualizing 3-dimensional objects. Complex scientifi c applications like the launch of the rockets, space exploration, etc., are not possible without the computers.
Government : The government uses computers to manage its own operations and also for egovernance.
The websites of the different government departments provide information to the users. Computers are used for the fi ling of income tax return, paying taxes, online submission of water and electricity bills, for the access of land record details, etc.
Home: Computers have now become an integral part of home equipment. At home, people use computers to play games, to maintain the home accounts, for communicating with friends and relatives via Internet, for paying bills, for education and learning, etc. Microprocessors are embedded in house hold utilities like, washing machines, TVs, food processors, home theatres, security devices, etc. The list of applications of computers is so long that it is not possible to discuss all of them here. In addition to the applications of the computers discussed above, computers have also proliferated into areas like banks, investments, stock trading, accounting, ticket reservation, military operations, meteorological predictions, social networking, business organizations, police department, video conferencing, tele-presence, book publishing, web newspapers, and information sharing.
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