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Introduction
Computer is an electronic device that is designed to work with Information. The term computer is derived from the Latin term ‘computare’, this means to calculate or programmable machine. Computer cannot do anything without a Program. Charles Babbage is called the "Grand Father" of the computer. The First mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards. 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.
Block Diagram of Computer
A computer can process data, pictures, sound and graphics. They can solve highly complicated problems quickly and accurately. A computer performs basically five major computer operations or functions irrespective of their size and make. These are
- it accepts data or instructions by way of input,
- it stores data,
- it can process data as required by the user,
- it gives results in the form of output, and
- it controls all operations inside a computer.
We discuss below each of these Computer operation
- Input: This is the process of entering data and programs in to the computer system. We should know that computer is an electronic machine like any other machine which takes as inputs raw data and performs some processing giving out processed data. Therefore, the input unit takes data from us to the computer in an organized manner for processing.
- Storage: The process of saving data and instructions permanently is known as storage. Data has to be fed into the system before the actual processing starts. It is because the processing speed of Central Processing Unit (CPU) is so fast that the data has to be provided to CPU with the same speed. Therefore the data is first stored in the storage unit for faster access and processing. This storage unit or the primary storage of the computer system is designed to do the above functionality. It provides space for storing data and instructions. The storage unit performs the following major functions:
- All data and instructions are stored here before and after processing.
- Intermediate results of processing are also stored here.
- Processing: The task of performing operations like arithmetic and logical operations is called processing. The Central Processing Unit (CPU) takes data and instructions from the storage unit and makes all sorts of calculations based on the instructions given and the type of data provided. It is then set back to the storage unit.
- Output: This is the process of producing results from the data for getting useful information. Similarly the output produced by the computer after processing must also be kept somewhere inside the computer before being given to user in human readable form. Again the output is also stored inside the computer for further processing.
- Control: The manner how instructions are executed and the above operations are performed. Controlling of all operations like input, processing and output are performed by control unit. It takes care of step by step processing of all operations inside the computer.
Functional Units
In order to carry out the operations performed by the computer, the computer allocates the task between its various functional units. The computer system is divided into three separate units for its operation. They are Arithmetic Logical Unit (ALU) After entering data through the input device it is stored in the primary storage unit. The actual processing of the data and instruction are performed by Arithmetic Logical Unit. The major operations performed by the ALU are addition, subtraction, multiplication, division, logic and comparison. Data is transferred to ALU from storage unit when required. After processing the output is returned back to storage unit for further processing or getting stored.
Business: Business clearly sees the interest as a way to enhance productivity and competitiveness. Some areas of business that are undergoing rapid changes are sales and marketing, retailing, banking, stock trading, etc. Sales representatives not only need to be better educated and more knowledgeable about their customer’s businesses, but also must be comfortable with computer technology. The internet has become a popular marketing tool. The world of cybercash has come to banking – not only smart cards but internet banking, electronic deposit, bill paying, online stock and bond trading, etc. Recreation and Entertainment: Our entertainment and pleasure-time have also been affected by computerization. For example:
- In movies, computer generated graphics give freedom to designers so that special effects and even imaginary characters can play a part in making movies, videos, and commercials.
- In sports, computers compile statistics, sell tickets, create training programs and diets for athletes, and suggest game plan strategies based on the competitor’s past performance.
- In restaurants, almost every one has eaten food where the clerk enters an order by indicating choices on a rather unusual looking cash register; the device directly enters the actual data into a computer, and calculates the cost and then prints a receipt. Government: Various departments of the Government use computer for their planning, control and law enforcement activities. To name a few – Traffic, Tourism, Information & Broadcasting, Education, Aviation and many others. Defence: There are many uses computers in Defence such as:
- Controlling UAV or unmanned air-crafts an example is Predator. If you have cable I would recommend watching the shows “Future Weapons" and “Modern Marvels". The show future weapon gives an entire hour to the predator.
- They are also used on Intercontinental Ballistic Missiles (ICBMs) that uses GPS and Computers to help the missile get to the target.
- Computers are used to track incoming missiles and help slew weapons systems onto the incoming target to destroy them.
- Computers are used in helping the military find out where all their assets are (Situational Awareness) and in Communications/Battle Management Systems.
- Computers are used in the logistic and ordering functions of getting equipments to and around the battlefield.
- Computers are used in tanks and planes and ships to target enemy forces, help run the platform and more recently to help diagnose any problems with the platforms.
- Computers help design and test new systems. Sports: In today's technologically growing society, computers are being used in nearly every activity.
Characteristics of computer
- Speed
- Accuracy
- Diligence
- Storage capacity/memory
- Versatility
- Reliability
- Power of remembering
- Compactness Speed:-Computer can process millions of instruction in seconds Same calculation that would have taken hours and day to complete can be completed in a few seconds using the computer The speed of computer is calculated in (MIPS) (millions of instruction per second) Accuracy:- A computer provides a high degree of accuracy Every calculation is performer with the same accuracy Diligence:- Computer can work for hours without any break or boredom It does not get tried It can perform complex Calculation with the same speed and accuracy from the start till the end Storage capacity/memory
- Computer can store very large amount of data
- We have many storage devices like CD, DVD etc Versatility :- Computers can be used to perform different types of tasks At one point of time you can type a document.the next moment you can listen to a song or watch a video Compactness :- Day by day computer size is decreasing with new technology
- Hybrid Computer Hybrid computer has features of both analogue and digital computer. It is fast like analogue computer and has memory and accuracy like digital computers. It can process both continuous and discrete data. So it is widely used in specialized applications where both analogue and digital data is processed. For example, a processor is used in petrol pumps that converts the measurements of fuel flow into quantity and price. On the basis of size, the computer can be of five types:
- Supercomputer Supercomputers are the biggest and fastest computers. They are designed to process huge amount of data. A supercomputer can process trillions of instructions in a second. It has thousands of interconnected processors. Supercomputers are particularly used in scientific and engineering applications such as weather forecasting, scientific simulations and nuclear energy research. First supercomputer was developed by Roger Cray in 1976.
- Mainframe computer Mainframe computers are designed to support hundreds or thousands of users simultaneously. They can support multiple programs at the same time. It means they can execute different processes simultaneously. These features of mainframe computers make them ideal for big organizations like banking and telecom sectors, which need to manage and process high volume of data.
- Miniframe computer It is a midsize multiprocessing computer. It consists of two or more processors and can support 4 to 200 users at one time. Miniframe computers are used in institutes and departments for the tasks such as billing, accounting and inventory management.
- Workstation Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other such types of applications which require a moderate amount of computing power and relatively high quality graphics capabilities. Workstations generally come with a large, high-resolution graphics screen, large amount of RAM, inbuilt network support, and a graphical user interface. Most workstations also have mass storage device such as a disk drive, but a special type of workstation, called diskless workstation, comes without a disk drive. Common operating systems for workstations are UNIX and Windows NT. Like PC, workstations are also single-user computers like PC but are typically linked together to form a local-area network, although they can also be used as stand-alone systems.
- Microcomputer Microcomputer is also known as personal computer. It is a general purpose computer that is designed for individual use. A PC can be defined as a small, relatively inexpensive computer designed for an individual user. PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. At home, the most popular use for personal computers is playing games and surfing the Internet. Although personal computers are designed as single-user systems, these systems are normally linked together to form a network. In terms of power, now-a-days high-end models of the Macintosh and PC offer the same computing power and graphics capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and Dell.
Generations of Computers
A generation of computers refers to the specific improvements in computer technology with time. In 1946, electronic pathways called circuits were developed to perform the counting. It replaced the gears and other mechanical parts used for counting in previous computing machines. In each new generation, the circuits became smaller and more advanced than the previous generation circuits. The miniaturization helped increase the speed, memory and power of computers. There are five generations of computers which are described below; First Generation Computers The first generation (1946-1959) computers were slow, huge and expensive. In these computers, vacuum tubes were used as the basic components of CPU and memory. These computers were mainly depended on batch operating system and punch cards. Magnetic tape and paper tape were used as output and input devices in this generation; Some of the popular first generation computers are; ENIAC ( Electronic Numerical Integrator and Computer) EDVAC ( Electronic Discrete Variable Automatic Computer) UNIVACI( Universal Automatic Computer) IBM- IBM- Second Generation Computers The second generation (1959-1965) was the era of the transistor computers. These computers used transistors which were cheap, compact and consuming less power; it made transistor computers faster than the first generation computers. In this generation, magnetic cores were used as the primary memory and magnetic disc and tapes were used as the secondary storage. Assembly language and programming languages
hardware and AI (Artificial Intelligence) software. The programming languages used in this generation were C, C++, Java, .Net, etc. Some of the popular fifth generation computers are; Desktop Laptop NoteBook UltraBook ChromeBook
