BANK EXAM ONLINE COACHING

Computer Awareness 1

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COMPUTER AWARENESSCOMPUTER AWARENESS

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Development of Computer

Input and Output Device

Memory

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Development of Computer: Introduction

• A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations. 

• Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries.

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History of Computer:

• 1830s: The first automatic digital computer was conceived by the English inventor Charles Babbage.

• 1848: English mathematician developed 'Boole's system', which became the basis of Boolean algebra, on which electronic computer switching theory and procedures are based:

• 1890: The 1890 US census was conducted by the method developed by Herman Hollerith who went on to set up the Tabulating Machine Company, later to become IBM.

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• 1906: Lee De Forest developed the electronic tube or electronic valve without which it would have been impossible to have made digital computers.

• 1924: International Business Machines (IBM Corporation) formed after merger of companies.

• 1939: Hewlett-Packard formed by David Hewlett and William Packard in a garage in California.

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• 1965: The first supercomputer, the Control Data CD6600, was developed.

• 1968: Intel founded by Robert Noyce.

• 1969: ARPANET, started by the US Department of Defence for research, is the original basis of what forms the internet.

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Types of computers • a) Analog Computers: Analog

computers are computers that measure physical quantities and convert them to numeric values. Analog computers are used mainly for scientific and engineering purposes.

• b) Digital Computers: Most computers are digital devices', i.e., they count the numbers that represent numerals, letters, or other special. symbols. Special purpose digital computers can be fixed permanently in the machine e.g. processors that are installed in automobiles to control fuel, braking systems etc.

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• c) Hybrid Computers: The features of analog and digital machines are combined to create a hybrid computing system. For example analog devices measure a-patient's vital signs like temperature, heart functions. These are then converted to numbers and supplied to the digital components that monitor the patient's vital signs. Any fluctuation can thus be noticed immediately.

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Input and Output Device: Introduction

• Before a computer can process your data, you need some method to input the data into the machine.

• INPUT DEVICES ARE:  Keyboard ,Mouse , Touch pad, Track Ball etc.

• OUTPUT DEVICES ARE:  CRT Monitor , Flat Panel Display, Ink Jet Printer ,Laser Printer etc.

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• KEY BOARD: The computer keyboard is used to enter text information into the computer, as when you type the contents of a report. 

• Mouse: The mouse pointing device sits on your work surface and is moved with your hand. 

Input Device

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• Touch pad: Most laptop computers today have a touch pad pointing device. You move the on screen cursor by sliding your finger along the surface of the touch pad. 

• Trackball: The trackball is sort of like an upside down mouse, with the ball located on top. You use your fingers to roll the trackball, and internal rollers sense the motion which is transmitted to the computer.

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OUTPUT DEVICES• CRT Monitor: The CRT monitor

contains a large cathode ray tube that uses an electron beam of varying strength to “paint” a picture onto the color phosphorescent dots on the inside of the screen.

• Flat Panel Display: A flat panel display usually uses an LCD screen to display output from the computer. The LCD consists of several thin layers that polarize the light passing through them.

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• Ink Jet Printer: For hardcopy output, you need some kind of printer attached to your computer. The most common type of printer for home systems is the color ink jet printer.

• Laser Printer: A laser printer produces good quality images by the same technology that photocopiers use. A drum coated with photosensitive material is charged, then an image is written onto it by a laser which makes those areas lose the charge.

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MEMORY

• The term memory identifies data storage that comes in the form of chips, and the word storage is used for memory that

exists on tapes or disks.

There are five types of memory

• RAM• ROM• PROM• EPROM• EEPROM

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Random Access Memory

1. RAM refers to read and write memory

2. This is in contrast to ROM  which permits you only to read data. 

3. Random access memory same as main memory.

4. RAM is volatile which means that it requires a steady flow of electricity to maintain its contents

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Read Only Memory

• There are certain essential functions that the computer must perform when if is switched on. These low-level or machine-level functions are carried out through a series of programs or micro programs.

• While both RAM and ROM are storage devices and can be accessed randomly, they differ in that data can be written onto RAM while ROM does not permit the user to write onto it.

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Programmable Read Only Memory• There are some types of read

only memory called Programmable Read-Only Memory . Critical or lengthy operations that are slowly carried out by software can be converted into microprograms and fused into a programmable read-only memory chip.

• A PROM is a memory chip on which you can store a program. But once the PROM has been used, you cannot wipe it clean and use it to store something else. Like ROMs, PROMs are non volatile.

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Erasable Programmable Read Only Memory

• An EPROM is a special type of PROM that can be erased by exposing it to ultraviolet light.

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Electrically Erasable Programmable Read Only Memory

• An EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge.

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