Computer

Computer

Computer is an electronic device that is designed to work with Information. The term computer is derived from the Latin term ‘computes’, this means to calculate or programmable machine. Computer can not do anything without a Program. It represents the decimal numbers through a string of binary digits. The Word 'Computer' usually refers to the Center Processor Unit plus Internal memory.

Father of Computer 

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.

Type of Computer 

The four basic types of computers are as under:

• 1​Supercomputer.
• 2​Mainframe computer.
• 3​Minicomputer.
• 4​Microcomputer.

Supercomputer 

The fastest type of computer. Supercomputers are very expensive and are employed for specialized application that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. Other uses of supercomputers include animated graphic, fluid dynamic calculations, nuclear energy research, and petroleum exploration.

The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently

Mainframe computer

Mainframe Computer is a powerful computer having multiple user interfaces. Primarily ‘mainframe’ referred to the large cabinets which housed the Central Processing Unit and the main memory. Mainframes can run uninterrupted for tens of years. The term RAS (reliability, availability, serviceability) is a very important characteristic of mainframe computer since it used for application where the thing has to be done with zero downtime. It is used for millions of smaller and simpler calculations and transactions, unlike supercomputers

                                                    Minicomputer

A minicomputer is a type of computer that possesses most of the features and capabilities of a large computer but is smaller in physical size.A minicomputer fills the space between the mainframe and microcomputer, and is smaller than the former but larger than the latter. Minicomputers are mainly used as small or mid-range servers operating business and scientific applications. However, the use of the term minicomputer has diminished and has merged with servers.A minicomputer may also be called a mid-range computer.

Microcomputer

 An electronic device with a microprocessor as its central processing  (CPU). Microcomputer was formerly a commonly used term for personal computer, particularly any of a class of small digital computers, whose CPU is contained on a single integrated  semiconductor chip. Thus, a microcomputer uses a single microprocessor for its CPU, which performs all logic and arithmetic operations. The system also contains a number of associated semiconductor chips that serve as the main memory for storing program instructions and data and as interfaces for exchanging data of this sort with periphelar equipment—namely, input/output devices (e.g., keyboard, video display, and printer) and auxiliary storage units. Smaller microcomputers first marketed in the 1970s contain a single chip on which all CPU, memory, and interface circuits are integrated.

Monitor

मॉनिटर ( Monitor )

मॉनिटर:- मॉनिटर एक आउटपुट डिवाइस है | इसको विजुअल डिस्प्ले भी कहा जाता हैं | यह देखने में टी वी होता है | Monitor एक सबसे महत्वपूर्ण आउटपुट डिवाइस है | इसके बिना कंप्यूटर अधूरा होता है | यह आउटपुट को आपनी स्क्रीन पर सॉफ्ट कॉपी के रूप में प्रदर्शित करता हैं | मॉनिटर द्वारा प्रदर्शित रंगों के आधार पर यह तीन प्रकार के होते हैं | 

मॉनिटर के प्रकार ( Types of Monitor )

• CRT Monitor
• Flat Panel Monitor
• LCD (Liquid Crystal Display)
• LED ( Light Emitting Diode)

CRT Monitor

CRT Monitor सबसे ज्यादा Use होने वाला Output Device हैं जिसे VDU (Visual display Unit) भी कहते हैं इसका Main Part cathode Ray tube होती हैं जिसे Generally Picture tube कहते हैं अधिकतर मॉनीटर में पिक्चर ट्यूब एलीमेंट होता है जो टी.वी. सेट के समान होता है यह ट्यूब सी.आर.टी. कहलाती है सी.आर.टी. तकनीक सस्ती और उत्तम कलर में आउटपुट प्रदान करती है CRT में Electron gun होता है जो की electrons की beam  और cathode rays को उत्सर्जित करती है ये Electron beam, Electronic grid से पास की जाती है ताकि electron की Speed को कम किया जा सके CRT Monitor की Screen पर फास्फोरस की Coding की जाती है इसलिए जैसे ही electronic beam Screen से टकराती है तो Pixel चमकने लगते हैं और Screen पर Image या Layout दिखाई देता हैं

Flate Panel Monitor

CRT तकनीक के स्थान पर यह तकनीक विकसित की गयी जिसमे कैमीकल व गैसों को एक प्लेट में रखकर उसका प्रयोग Display में किया जाता है यह बहुत पतली स्क्रीन (Screen) होती है| flat Panel वजन में हल्की तथा बिजली की खपत कम करने वाली होती है इसमें द्रवीय क्रिस्टल डिस्प्ले (Liquid Crystal Display-LCD) तकनीक प्रयोग की जाती है LCD में CRT तकनीक की अपेक्षा कम स्पष्टता होती है इनका Use Laptop आदि में किया जाता हैं

LCD ( Liquid Crystal Display )

CRT Monitor बिलकुल टेलीविजन की तरह हुआ करते थे  Technology के विकास के साथ Monitor ने भी अपने रूप बदले और आज CRT Monitor के बदले LCD Monitor प्रचलन में आ गए है यह Monitor बहुत ही आकर्षित होते हैं Liquid Crystal Display को LCD के नाम से भी जाना जाता हैं यह Digital Technology हैं जो एक Flat सतह पर तरल क्रिस्टल के माध्यम से आकृति बनाता हैं यह कम जगह लेता है यह कम ऊर्जा लेता है तथा पारंपरिक Cathode ray tube Monitor की अपेक्षाकृत कम गर्मी पैदा करता हैं  यह Display सबसे पहले Laptop में Use होता था परन्तु अब यह स्क्रीन Desktop Computer के लिए भी प्रयोग हो रहा हैं |

LED ( Light Emitting Dioade )

LED मॉनीटर आज बाजार में मॉनीटर के नवीनतम प्रकार हैं। ये फ्लैट पैनल हैं, या थोड़ा घुमावदार डिस्प्ले जो बैक- लाइटिंग के लिए कोल्‍ड कैथोड फ्लोरोसेंट की बजाय बैक-लाइटिंग के लिए light-emitting diodes का उपयोग करते हैं। एलईडी मॉनीटर, सीआरटी और एलसीडी की तुलना में बहुत कम बिजली का उपयोग करते है और उन्हें पर्यावरण के अनुकूल माना जाता है।

Computer generations

Computer Generations 

• First Generation 
• the period of first generation was 1942-1954.
• First generation of computer started with using Vacuum tubes as the basic components for memory and circuity for CPU ( Central Processing Unit). These tubes like electric bulls produced a lot heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organisations.
• In this generation mainly batch processing operating system were used. In this generation Punched cards, Paper tape, Magnetic tape Input & Output device were used.
• There were Machine code and electric wired board language used.
• The main features of First Generation are:
• Vacuum tube technology 
• Unreliable
• Supported Machine language only
• Very costly 
• Generate lot of heat
• Slow Input / Output device
• Huge size
• Need of A.C.
• Non portable
• Consumed lot of electricity 
• Some computer of this generation were:
• Second Generation
• The period of second generation was 1952-1964.
• This generation Using the transistor were cheaper, consumed less power, more compact in size, more reliable and faster then the first generation machines made of used as primary memory and magnetic tape and magnetic disks as secondary storage devices.
• In the generation assembly language and high level programming language like FORTRAN, COBOL were used.
• There were Batch processing and Multiprogramming Operating system used.
• The main features of Second Generation are:
• Use of transistors 
• Reliable as compared to First generation computers
• Smaller size as compared to first generation computers
• Generate less hear as compared to First generation computers
• Consumed less electricity as compared to First generation computers 
• Faster then first generation computers
• Still very costly 
• A.C needed
• Support machine and assmebly languages
• Some computer of this generation were:
• Third Generation
•  The period of third generation was 1964-1972.
• The third generation of computer is marked by use of Integrated Circuits (IC's) in place of transistors. A single I.C has many transistors, resistors and capacitors along with the associated circuitry. The I.C was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient.
• In this generation Remote processing, Time-sharing, Real-time. Multi-programming Operating System were used.
• High level language (FORTRAN-II TO IV, COBOL, PASCALPL/L, BASIC, ALGOL-68 etc.) were used during this generation.
• The main features of Third Generation are:
• IC used
• More reliable 
• Smaller size 
• Generation less heat
• Faster
• Lesser maintenance 
• Still costly
• A.C needed
• Consumed lesser electricity 
• Support high level language
• some computer of this generation were:
• IBM-360 series, Honeywell-6000 series
• Fourth Generation
• The period of fourth generation was 1972-1990.
• The fourth generation of computers is marked by the use of VERY LARGE SCALE INTEGRATED (VLSI) circuits. VLSI Circuit having about 500 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputer of fourth generation. Fourth Generation computers become more powerful, compact, reliable, and affordable. As a result. It gave rise to personal computer (PC) revolution.
• In this generation Time sharing, Real time, Networks, Distributed Operating System were used.
• All the higher level language like C and C++, DBASE etc. were used in this generation.
• The main features of Fourth generation are:
• VLSI Technology 
• Very cheap
• Portable and reliable
• Use of PC's
• Very small size
• Pipeline processing 
• No. A.C. needed
• Fifth Generation
• The period of fifth generation is 1990 till date.
• In the fifth generation, the VLSI technology become ULSI ( Ultra Large Scale Integration) technology, resulting in the production  of microprocessor chips have ten million electronic computers.
• This generation is on parallel processing hardware and AL ( Artificial Intelligence) software.

Introduction to computer

कंप्यूटर शब्द इंग्लिश शब्द के " Compute" शब्द से बना है | जिसका हिंदी में अर्थ " गणना " करना होता है इसलिए इसे गणक या संगणक भी कहा जाता है इसका अविष्कार Calculation करने के लिए हुआ था पुराने समय में Computer का  Use केवल Calculation करने के लिए किया जाता था | किन्तु आज के समय में इसका Use - Documents create, E-mail, Listening music, Videos, Play games, Data base, Preparation के साथ साथ बहुत से अन्य कामो में किया जाता हैं जैसे - बैंकों में, शैक्षणिक संस्था में, कार्यालयों में, घरों में, दुकानों में, Computer का उपयोग किया जा रहा हैं
Computer को कार्य करने के लिए Software और Hardware की आवश्यकता होती है 

कंप्यूटर के जनक 
कंप्यूटर के जनक चार्ल्स बैबेज (Charles Babbage) को कहा जाता हैं
Full form of computer 

• C- Commonly 
• O- Operated 
• M- Machine
• P- Particularly
• U- Used 
• T- Technical
• E- Educational 
• R- Research