Computer System
Introduction
The word computer is derived from the Latin word 'computare', which means to calculate. The computer is defined in the Oxford dictionary as "an automatic electronic device (apparatus) for making calculations or controlling operations that are expressible in numerical or logical terms."
A computer works on the basic sequence: Input, Process, Output and Storage.
Definitions of computer
- A computer can be defined as a multipurpose, multi-programmable electronic data processing device that is capable of accepting input, processing it and providing information as output at fast speed.
- It is an electronic device which can perform computation as well as logical action at enormous (fast) speed.
- A computer is an electronic device which takes input data from input devices, stores it, processes it and produces output.
Characteristics of a Computer System
- Speed: A computer can work very fast. It takes only a few seconds for a calculation that we would take hours to complete. A computer can perform millions of instructions, or even more, per second.
- Automatic: It carries out a job without any human interaction once we give the appropriate data and instruction. A computer can do the operation automatically as it is already programmed to do so.
- Accuracy: A computer performs every calculation with the same accuracy. If the data and instructions given are correct, then the result given by the computer will always be accurate. The term GIGO (Garbage In Garbage Out) applies in this context: if we give wrong data or instruction, the computer gives us wrong output.
- Diligence: A computer is free from tiredness and lack of concentration. It is capable of doing a required task again and again without affecting its speed, accuracy and efficiency. It never gets tired, bored or lazy to do the job.
- Versatility: A computer can perform different types of task one by one. It has a wide range of application areas and can do many types of jobs.
- Reliability: The results obtained by the computer are very reliable, but this is true only when the data or program given to the computer is correct or reliable.
- Storage: The computer has inbuilt memory where we can store a large amount of data. We can also store data in secondary storage devices such as hard disk, pen drive, etc., which can be kept outside the computer.
- Resource sharing: Computers have the capability to connect with each other. This has made the sharing of resources costless. Apart from devices, data and information can also be shared among a group of computers.
- No feeling: A computer does not have feelings or emotions, taste, knowledge and experience.
- No intelligence (IQ): A computer is a dumb machine and it cannot do any work without instruction from the user. A computer cannot take its own decision.
History of Computer System
1. Mechanical Era
| S.No | Computer's Name | Invented by | Invented in | Function |
|---|
| 1 | Abacus | Chinese | 3000 yrs ago (500 BC) | To serve as a calculating tool |
| 2 | Napier's Bone | John Napier | 1617 A.D | Calculation of product and quotient of numbers |
| 3 | Slide Rule | William Oughtred | 1622 A.D | Instrument for multiplication and division |
| 4 | Pascaline | Blaise Pascal | 1642 A.D | Adding and subtracting 8 figures |
| 5 | Leibniz's Calculator | Gottfried Wilhelm Leibniz | 1694 A.D | First calculator to perform operations |
| 6 | Difference and Analytical Engine | Charles Babbage | 1822 and 1837 A.D | Can hold data temporarily for processing and result |
2. Electro-mechanical Era
| S.No | Computer's Name | Invented by | Invented in | Function |
|---|
| 1 | Mark-I | Howard Aiken | 1944 A.D | To execute long computation |
| 2 | ABC (Atanasoff Berry Computer) | John Vincent Atanasoff | 1939 A.D | Capacity to store data in binary form and electronic logic circuit, to perform addition and subtraction |
| 3 | Colossus | Tommy Flowers | 1944 A.D | To help decipher the Lorenz-encrypted messages between Hitler and his generals during the world war |
| 4 | Boolean Algebra | George Boole | 1847 A.D | Designed 0's and 1's in binary form for false and true |
3. Electronic Era
| S.No | Computer's Name | Invented by | Invented in | Function |
|---|
| 1 | ENIAC (Electronic Numerical Integrator And Computer) | John Mauchley and J.P Eckert | 1946 A.D | To calculate artillery firing tables |
| 2 | EDSAC (Electronic Delayed Storage Automatic Computer) | Maurice Wilkes | 1949 A.D | Used mercury delay lines for memory and vacuum tubes for logic |
| 3 | EDVAC (Electronic Discrete Variable Automatic Computer) | John Mauchley, J.P Eckert | 1952 A.D | Automatic addition, subtraction, multiplication, division and automatic checking |
| 4 | UNIVAC (Universal Automatic Computer) | John Mauchley, J.P Eckert | 1951 A.D | Commercial data processing |
Applications of Computer System
- Education: Teachers can make report cards, maintain attendance records of students, and create presentations to teach students about various topics.
- Offices: Almost all offices use computers to type letters, send and receive emails, store customer details, make presentations, train new employees, and do data analysis and calculations.
- Transportation: We can book online tickets from a computer using the internet, including railway and airline ticket reservation and printing. Computers help to control air traffic.
- Hospitals: Computers help doctors in their diagnosis and laboratory tests. Hospitals maintain details of each patient admitted.
- Bank: With the use of computers, electronic transfer of funds from one account to another is possible. Computers are used to maintain ledgers, handle transactions, and make entries in passbooks.
- Film: Computers are used to create special effects in movies and in composing, editing, recording and reproducing music and sound effects.
- Communications: Email, e-fax, internet, etc. are computer-based communications. The integration of the computer and internet is the backbone of recent communication.
- Hotel management: Computers are used for front desk management, personnel management, preparing trial balance sheets, documentation, etc.
Generations of Computer
The term generation indicates the stage of evolution or development of a computer based on the type of technology used in its construction over a period of time. Each new generation has made the following changes in computer characteristics:
- Increased speed
- Increased storage capacity
- Increased reliability
- Reduced size of computer
- Reduced cost of computer
- Reduced heat produced by computer
Computers can be divided into 5 generations depending on the technology used:
- First generation computer (1945 - 1956 AD)
- Second generation computer (1956 - 1964 AD)
- Third generation computer (1964 - 1971 AD)
- Fourth generation computer (1972 - Present)
- Fifth generation computer (Present and beyond)
1. First generation computers
- Vacuum tube is used as the main component.
- Magnetic drum is used for primary memory.
- Magnetic tape is used as secondary memory.
- Punch card for input.
- Printout display is used for output.
- Limited storage capacity (1 KB to 4 KB).
- Large in size.
- Operating speed was in the millisecond range.
- Expensive (use machine language for programming).
- Generated a large amount of heat.
- Examples: ENIAC, EDVAC, UNIVAC, IBM 1650, IBM 705, etc.
2. Second generation computers
- Transistor is used as the main component.
- Magnetic core memory is used as primary memory.
- Magnetic tape is used for secondary memory.
- Assembly language used at the beginning; at the end, high level language is used.
- Reduced heat generated by the computer compared to the first generation.
- Punch card is used as an input device.
- Printout display is used as an output device.
- Large storage capacity in this generation.
- Higher speed than the first generation.
- Examples: IBM 1401, IBM 730, 400 series, etc.
3. Third generation computers
- IC (Integrated Circuit) is used as the main component.
- Magnetic disk is used for secondary storage/memory.
- Semiconductor is used for primary memory.
- Keyboard and mouse are used as input devices.
- Monitor is used as an output device.
- Started to use an operating system.
- Higher processing speed than 2nd generation computers.
- Operation speed in the nanosecond range.
- Uses high level language for programming.
- Examples: IBM 360, IBM 370, etc.