Information and communication technologv I Target JRF ICT I with MCQs (for CBSE UGC NET Paper 1) By Navdeep Kaur
Contents Information and communication technology ICT 1 Data Representation, Conversion table 2 Types of data representation 3 Binary, Decimal, Octal, Hexadecimal conversion 4 All Computer Abbreviations 5 MCQs Solving with tips & tricks
Concepts of data representation in digital compute . Data and instructions cannot be entered and processed directly into . Any type of data be it numbers, letters, special symbols, sound or computers using human language. pictures must first be converted into machine-readable form i.e. binary form. Due to this reason, it is important to understand how a computer together with its peripheral devices handles data in its electronio circuits, on magnetic media and in optical devices.
Data representation in digital circuits Electronic components, such as microprocessor, are made up of millions of electronic circuits. The availability of high voltage(on) in these circuits is interpreted as 1' while a low voltage (off) is interpreted as '0'. This concept can be compared to switching on and off an electric circuit. When the switch is closed the high voltage in the circuit causes the bulb to light (1' state).on the other hand when the switch is open, the bulb goes off ('0' state). This forms a basis for describing data representation in digital computers using the binary number system .
Data representation on magnetic media . The laser beam reflected from the land is interpreted, as1 The laser entering the pot is not reflected. This is interpreted as 0. The reflected pattern of light from the rotating disk falls on a receiving photoelectric detector that transforms the patterns into digital form. The presence of a magnetic field in one direction on magnetic media is interpreted as 1; while the field in the opposite direction is interpreted as "o". Magnetic technology is mostly used on storage devices that are coated with special magnetic materials such as iron oxide.
Data representation on optical media . In optical devices, the presence of light is interpreted as 4, while its absence is interpreted as . Optical devices use this technology to read or store data. Take example of a CD-ROM, if the shiny surface is placed under a powerful microscope, the surface is observed to have very tiny holes called pits. The areas that do not have pits are called land.
Reason for use of binary system in computers It has proved difficult to develop devices that can understand natural language directly due to the complexity of natural languages. However, it is easier to construct electric circuits based on the binary or ON and OFF logic. All forms of data can be represented in binary system format. Other reasons for the use of binary are that digital devices are more reliable, small and use less energy as compared to analog devices. . .
Bits, bytes, nibble and word . The terms bits, bytes, nibble and word are used widely in reference to . Bits: can be defined as either a binary, which can be 0, or 1.lt is the computer memory and data size. basic unit of data or information in digital computers. Byte: a group of bits (8 bits) used to represent a character. A byte is considered as the basic unit of measuring memory size in computer. A nibble: is half a byte, which is usually a grouping of 4 bits. Word: two or more bits make a word. The term word length is used as the measure of the number of bits in each word. For example, a word can have a length of 16 bits, 32 bits, 64 bits etc.
Conversion table Traditional units Decimal for comparison NameSymbol Binary Number of bytes Equal to Name IEC Decima Number of bits Equal to 1,024 1024 B 1,000 1000 bit Kilobit kbit 103 Megabi Mbit 106 1,073,741,824 1024 MB Gigabit Gbit 10 1,099,511,627,776 1024 GB Terabit Tbit 1012 Petabit Pbit 1015 1,152,921,504,606,846,976 1024 PBait Ebit 1018 1,180,591,620,717.411,303,424 1024 EB Zettabit Zbit 1021 Yottabit Ybit 1024 10 2 KilobytekB Megabyt MB 220 Gigabyte GB 230 1,048,576 1024 kB 1,000,000 1000 kbit 1,000,000,000 1000 Mbit Terabyte TB Petabyte PB Exabvte EB Zettabvte ZB Yottabyte YB 40 50 60 70 80 1,000,000,000,000 1000 Gbit 1,000,000,000,000,000 1000 Tbit 1,000,000,000,000,000,000 1000 Pbit 1,000,000,000,000,000,000,000 1000 Ebit 1,000,000,000,000,000,000,000,000 1000 Zbit 1,125,899,906,842,624 1024 TB 2 2 2 2 1,208,925,819,614,629,174,706,176 1024 ZB
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