Important One Liner Computer General Knowledge MCQ,s JOA IT 939

 Important One Liner Computer General Knowledge 


computer awareness joa IT 939

Computer Facts 

    • 2 December is observed as Computer Literacy Day. 
    • India has announced New Computer Policy in 1984. 
    • First computer (made in India) is 'Siddhartha’, which was manufactured by Electronics Corporation of India.
    • First computer in India was installed in the Main Post Office of Bangalore on August 16, 1986.
    • First Pollution Free Computerized Petrol Pump of India is in Mumbai. 
    • First Computer University (in Private Sector) in India is Rajeev Gandhi Computer University.
    • Bangalore (now Bangalore) is also known as the Silicon Valley of India.
    • First Indian News Paper to be available on the Internet is 'The Hindu'. 
    • First Indian magazine to be available on Internet is 'India Today' 
    • First Indian political party which has created its website on internet is 'Bharatiya Janata Party 
    • Super Computers developed in the World 
    • First Super Computer of the world is CRAY K-1-S, developed by the Cray K Company of the U.S.A. 
    • Mainly there are three types of Computer, Digital, Analog and Hybrid.

Deep Blue' is a Super Defeated World Chess Champion Garry Kasparov. This Supercomputer is able to do the work equivalent to the work of 32 computers and can think 20 crore steps of chess in 1 second. 

First Electronic Digital Computer of the world is ‘ENIAC'. Most popular Operating System in the world is WINDOWS. USENET is a link to connect all the universities. 

First book on Personal Computers was written by Ted Nelson. The book of Ted Nelson, 'Soul of New Machine', won the Pulitzer Prize. First magazine on computers is ‘Computer and Automation'. First home Computer is Commodore VIC / 20. 


  • First Practical Digital computer is UNIVAC. FORTRAN is the first Programming Language.
  • PROLOG is the language of the language of the fifth generation of computers. J.S. Kilbi developed the IC chips. 
  • A computer error is known as Bug. 
  • C-DAC (Centre for Development and Advanced Computing) was established in Pune in 1988. 

Super Computers developed in India Name Manufacturer FLO SOLVER NAL, Bangalore PARAM-10000 C-DAC, Pune CHIPP - 16 C-Dot, Bangalore MULTIMICRO IIS, Bangalore MACH IIT, Bombay PACE DRDO 

Super computer PARAM - 10000, having the capacity of 1 billion calculations per second, was made by the scientists of C-DAC of Pune on March 28, 1998. The main credit for the development of the PARAM-10000 goes to Dr. Vijay P. Bhaskar, Executive Director of C-DAC, Pune. 

  • National Aeronautics Laboratories, Bangalore was the first in India to develop a Supercomputer named FLO SOLVER.
  • Laser Printers are the fastest printers. 
  • IBM (International Business Machine) is an American computer company. 
  • Computer virus is a man made digital parasite, which corrupts (infects) the known as “File corrupter'. 
  • Modem is a device which connects the computers and works based on telephone 
  • file and lines. and Year) known development of computers started in India in 1955. small palm sized 
  • Y-2 K was a technical problem, associated with the calendar (Date, Month as “Millennium Bug'. 
  • The Indian Institute of Science, Bangalore has developed 'Simputer', which is a touch screen computer. 
  • First Supercomputer in India is in Bangalore (Karnataka). 
  • Vellanad of Thiruvananthapuram district in Kerala has been declared the first fully computerised village of India.
  • PC Home computer, Electronic notebook etc. are the examples of micro computer 

Some Operating Systems used in micro computers are CP / M, Mac OS (Apple), DOS, Pro DOS, MS DOS / PC DOS, XENIX, WINDOWS, LINUX etc. Linus Benedict Torvalds, creator and coordinator of the Unix-like Operating System. Linus was born in Helsinki, Finland on December 28, 1969. 

On Sept. 17, 1991 Linus completed the first version of Linux. He made the wisest decision in Operating System history by releasing Linux under General Public Licence, thereby making it open and free to all.


He is one of the pioneers who advocated the idea of free software and thereby changed the software market. 

A computer may be used to control purely mechanical action. It has two main parts :

(i) Hardware and (ii) Software. 

Hardware Important MCQ,s

Computers perform some operations to solve problems. For this the various units of a computer system must perform and co-ordinate all operations. 

Computers have three main units:

1. Input unit,

2. Processing unit and

3. Output unit.

These are the physical units of a computer system. These units constitute the hardware of a computer. 

  • The computer has its own internal language'. 
  • The computer is essentially made of electronic components. All these components are capable of generating any one of the two states, either a low (or a 0 volt) or a high (say 5 volts). 

It is difficult to always talk in terms of currents and voltages to represent information. Therefore, computer scientists use a special convention. A high is symbolically represented by a 'l' and a low is represented by a ‘O'. The 1s and Os are known as binary digits, or in short bits' (the term 'binary' refers to something that has two parts). 

Computers always work with bits. They do not understand any other form. Computer scientists use a combination of 8 bits taken together to represent various symbols. 

Because every bit can take one of 2 possible values, the total number of combinations possible, using 8 bits, the computer can represent 256 different symbols.

This is enough to cover our entire range of alphabets, numbers and other special characters like $,@, +, * etc. Such a combination of 8 bits is called a byte. 

  • To build complex information like paragraphs and mathematical equations, we would need a larger number of bytes or characters. Thus we have the kilobyte, megabyte and gigabyte. 
  • In computers information is represented using multiples of 8 (23) bits, since 8 bits are the smallest unit of information. Therefore, higher units are expressible in multiples of 2(3) 

  • The power of two closest to a kilo (1000) is 20 – 1024, and is equal to 1 million bytes Megabytes is used in a more conventional sense or 1000 kilobytes. 
  • A gigabyte refers to 1000 megabytes approximately or 1 million kilobytes. 
  • The earliest computers were designed so that their components could work with 8 bits at a time. 
  • While the earliest machines were 8-bit machines, contemporary computers can work with 16, 32 and even 64 bits. This is called the data width of the computer. 
  • The basic elements of computers that can signal a 1 or a () are called flip-flops. It is a simple electrical device and can either be a 'Q' or a '1', which means that the flow of current is either inward or outward. 
  • Modern computers use a very tiny set of flip-flops known as a register. The most important characteristic of these registers is that the binary digits can be stored in them using certain voltages. 
  • The entire independent circuits can be designed on a small piece of a semiconductor material like silicon.
  • Silicon is obtained from sand and is a poor conductor of electricity. But, by chemical processes, the surface and the interior of a silicon chip’ are modified to give it electronic capabilities. Such miniature circuits are called Integrated Circuits (IC). 
  • By 1971, engineers were able to put a few component switches necessary to build a complete computer on a single chip of silicon. This tiny silicon chip was called the microprocessor. 
  • Because the computer is a binary machine, it performs mathematical operations using the binary number system. 
  • The binary number system is similar to the decimal system where we use ten digits, 0, 1, 2, 3.... 8, 9 to represent all numerical values. The only difference is in the number of digits used. 
  • The computer converts all decimal numbers into binary numbers or combinations of bits. Then by acting upon individual bits, it can perform the required mathematical operation addition, subtraction, etc. 
  • The internal circuits that can perform mathematical operations on bits are usually made of two or more logic gates. Logic gates are components that generate a 1 or a 0 depending on the input. 
  • The three basic logic gates are AND, OR and NOT 

A computer is organized into three basic units :

Central Processing Unit (CPU)

Memory Unit (MU)

Input / Output Unit

1. Central Processing Unit (CPU) 

The CPU is the part of a computer that performs the main function of information processing. The memory unit stores data. The computer supplies processed information back to the users using special output devices.

The Central Processing Unit CPU, is the most important part of the computer. It is called the brain of the computer. It makes all the required calculations and processes data. 

The CPU can be divided into three main components : (a) ALU (b) CU and (C) Registers. 

(a) The Arithmetic and Logic Unit (ALU): ALU performs all the mathematical and logical operations on the information supplied to the CPU. 

(b) Control Unit (CU): This unit directs the working of the CPU. It fetches instructions (Programs) from the memory and, according to the instructions, controls the flow of data between the ALU and other parts of the computer. 

(c) Registers: Registers are storage locations that hold instructions or data while the CPU is using them. The registers consist of flip-flops and the registers used by the CPU are the fastest memory elements in the computer. In contrast, the memory unit holds instructions and data before or after the CPU processes these. 

Main attributes of CPU 


  • Data Width: It refers to the number of bits of data that can be manipulated within the CPU at one given time. 
  • The data width of a computer is also called its word size. 
  • Computers have data widths ranging from 8 to 64 bits. 
  • A higher data width means the CPU is capable of processing data faster. A CPU with a higher data width is more powerful. 

(b) Address Range : Address range refers to the amount of memory that can be directly read or written by the CPU. 

(c) Clock Speed: The speed of the CPU is known as Clock Speed. The computer is essentially composed of tiny devices that can be put on or off to indicate 1 or 0.

At Any moment several thousand such devices change their state. To Synchronise 

  • the change of all these components the CPU uses an internal clock. 1 MHz = 1million 'ticks' per second, 1 GHz = 1000 MHZ 
  • With every tick of this clock all switches that need to change their position do so in perfect harmony. 
  • The larger the number of ticks per second the faster is the speed of the CPU. The ticks per second of the internal clock are measured in megahertz and gigahertz. 
  • Hertz is a unit of frequency . 
  • Higher the clock-speed, faster the computer. Unit (MU) 

2. Memory The memory unit stores all instructions and data for the CPU. Memory Unit is an important part of the computer system. The storage device of a computer system is known as memory. The Memory Unit can receive data, hold it and deliver according to the instructions from the control unit. 

Memory is of two kinds : (a) Primary and (b) Secondary. 

(a) Primary Memory It is often referred to as the working memory or the main memory of a computer system. It is capable of sending and receiving data at a very high speed. It is temporary in nature i.e. Data stored in primary memory are lost when the computer is switched off. So it is also called volatile memory. Example of primary memory is RAM. 

  • Primary memory is directly accessible to the CPU. It must be able to provide data very quickly. 
  • The two basic kinds of primary memory are the Random Access Memory (RAM) and the Read Only Memory (ROM). 
  • The RAM is a read/write memory.
  • The CPU can change the contents of the RAM at any time. In addition, RAM is volatile. 
  • The RAM capacity greatly influences the computing ability of the computer. Capacity is usually measured in kilobytes and megabytes. The ROM can not be altered. 
  • Information is stored on the ROM at the time of its manufacture. The information might be in the form of crucial instructions that govern the working of the computer 
  • The ROM is non-volatile and retains its information even after the power is turned off. 
  • The PROM (Programmable Read Only Memory), however, has the option of being programmed, i.e. the manufacturer of the computer may choose to load a program designed by his company into this PROM, and then the computer would use this PROM like any other ROM. 

(b) Secondary Memory It is used to store data for a long term. It operates at a much slower rate than primary memory. Secondary memory is permanent in nature, so it is also called non-volatile. It is also cheaper than primary memory. Examples of secondary memory are floppy disks, hard disks, magnetic tapes etc. 

  • Primary memory is fast but expensive. To reduce storage costs, computers also use secondary memory. 
  • It is not directly accessible to the CPU. Information is moved from the secondary memory to the primary memory first and then to the CPU. 
  • Common examples of secondary memory are floppy diskettes, hard (fixed) discs and magnetic tapes. A 
  • A floppy diskette is a plastic disk coated with magnetic 
  • Special devices known as disk drives are capable of reading from and writing to floppies using a special magnetic 'head'.
  • Any piece of information stored on a floppy diskette can be directly accessed. Magnetic tapes are long plastic tapes coated with magnetic material. 
  • Magnetic tapes can store far larger amounts of data than the floppy diskette. But a problem with magnetic tapes is that information can not be accessed directly as in the case of floppy diskettes. 
  • The third type of medium, called fixed or hard disks, are more or less similar to the floppy diskette. But one hard disk drive contains several discs of a hard material. 
  • Another popular storage medium is the compact disk (CD). Unlike the media described above, CDs are an “optical medium. 
  • An optical medium is one where the properties of light are used for the medium to perform its basic functions. 
  • Conventional CDs are made of a special kind of plastic. 
  • The CD is read using a laser beam . 
  • Secondary memory is much slower, but it is non-volatile and can be used to store information for long periods of time. 

3. Input/Output 

  • Input unit enables us to enter (or “Input") data into a computer. The common input devices are keyboard and mouse.
  • Similarly, a physical channel that permits a computer to convey the processed information to the outside world. Devices that permit such a function are called 'outpuť devices. 
  • Output unit enables the computer to show us the result and the information that we want. The common output devices are monitor, printer and speakers. 
  • Input and output devices are indispensable, but are not a part of the CPU. They are also called peripheral devices, suggesting that they lie on the periphery of the CPU. 
  • These devices are also called an interface, because they translate information for man and machine. 
  • The most popular input device used in contemporary computers is the keyboard. 
  • Another way to input information into a computer is to use an Optical Mark Reader (OMR). Optical Mark Readers are capable of reading specially prepared forms. These forms have a provision for black marks to be made using a pen or a pencil in a specific position. 
  • Most competitive examinations that deal with a large number of students usually use this system. 
  • There has to be a physical channel that permits users to supply information to the computer.
  • Devices that permit users to supply information to the computer are called 'input' devices. 

Banks use another input device called a Magnetic Ink Character Reader (MICR). Special numbers are written on bank cheques using magnetic ink and in a particular style to write different numbers. The MICR passes over the words or characters, examines the shape of the magnetic field created by the character, and is thus able to recognize it. 

Bar codes are often imprinted on products in merchandise stores. A bar code consists of several parallel vertical lines of different thickness that represent the binary digits. 

  • The bits form a code that can be used to identify the object on which the bar code is imprinted. A barcode reader is used to read the bar codes by detecting the bars by using light 
  • The bar code can represent information like the price of the product or its date of expiry etc.
  • Menu-driven programs, where the user sets the host of on-screen choices, sometimes use another input device called the mouse. 
  • The mouse is a pointing device. It can be gripped in the palm of the hand and moved over a horizontal surface. The motion of the mouse can be monitored by the computer in different ways. 
  • The movement is measured and transmitted to the computer. This generates a corresponding movement of an on-screen marker called a cursor from one option to another. 
  • To select an option the user presses one of the mouse's buttons, 
  • Another input device is a digital camera. A digital camera has a circuit that is sensitive to light. 
  • A The two most common devices are the Visual Display Unit (VDU) and the printer. 
  • A Visual Display Unit (VDU) uses a cathode ray tube to display information. To represent any character, VDU illuminates a particular pattern of these dots. These dots are also known as pixels, a short form for picture elements. 
  • Printers print characters on paper or other similar mediums. 
  • Printers come in three popular versions : dot matrix printers, ink-jet printers and laser printers. 
  • Dot matrix printers print characters in the form of combinations of very tiny dots. The printing head aligns its ‘pins' to match a particular pattern of dots. Ink-jet printers spray jets of ink onto the paper to print any character. The characters are absolutely smooth as ink is sprayed in a continuous flow.
  • Laser printer, uses a laser beam to actually burn the characters onto the paper. We need to issue the computer a detailed sequence of instructions that it needs to follow to operate upon any data. Such a sequence is called a program. 
  • A program may directly be written to the RAM or may be stored in some form of secondary memory. 
  • It may be transferred from the secondary memory to the RAM as and when required 
  • Execution of a program means that data is moved around in the CPU according to a well-detailed sequence by the programme. 
  • Computer programs are written using special languages called programming languages. 
  • There are several programming languages. Each language has its own ‘grammar' called its syntax.


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