Computer Knowledge PDF

Basics of computers and computer Applications for SSC & Railway Exams We Exam Pundit Team, has made “BOOST UP PDFS” Series to provide The Best Free PDF Study Materials on All Topics of Reasoning, Quantitative Aptitude, English Section and General awareness section....

Basics of computers and computer Applications for SSC & Railway Exams We Exam Pundit Team, has made “BOOST UP PDFS” Series to provide The Best Free PDF Study Materials on All Topics of Reasoning, Quantitative Aptitude, English Section and General awareness section. This Boost Up PDFs brings you questions in different level, Easy, Moderate & Hard, and also in New Pattern Questions. we also providing all the study materials for SSC & RRB exams. Each PDFs contains 50 Questions along with Explanation. For More PDF Visit: pdf.exampundit.in BASICS OF COMPUTERS AND COMPUTER APPLICATIONS S.no Contents Page number 1 Introduction of Computer 2 2 Generation of Computer 3 3 Components of computer 7 4 Input and output devices 9 5 Computer Memory 14 6 Memory unit 18 7 Programming Languages 19 8 Computer Network Types 19 9 Logic gates and Boolean operations 21 10 Number System 24 11 Computer security 26 12 Shortcut keys 31 13 Definitions and terminologies 42 14 Extension 52 15 Abbreviations 55 16 Fathers and Inventers of Computer Field 60 17 Applications of computer 60 Page 1 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Introduction of Computer  A computer is a machine or device that performs processes, calculations and operations based on Instructions provided by a software or hardware program. It is designed to execute applications and provides a variety of solutions by combining integrated hardware and software components.  A computer system consists of hardware and software components  Hardware is the physical equipment such as the case, storage devices, key boards ,moniters,cables,speakers and printers  Software is the operating systems and programs. 1. The operating system instructs the computer how to operate 2. Programs or applications perform different functions  COMPUTER stands for Common Operating Machine Purposely Used for Technological and Educational Research. Information processing cycle  It is a process of events in processing information which includes input, processing, storage and output. These processes work together & repeat over & over 1. Input –Entering data into the computer 2. Output-Performing the operation on the computer 3. Output-Presenting the result 4. Storage-Saving data program or output for future use Page 2 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  A Computer is an electronic device that takes raw data (unprocessed) as an input from the user and processes it under the control of a set of instructions (called program), produces a result (output), and saves it for future use. Generation of Computer  Growth in the computer industry is determined by the development in technology.  Based on various stages of development, computers can be categorized into different generations. First Generation (1942-1955): Hardware: The hardware used in the first generation of computers were:  Vacuum Tubes  Punch Cards. Features: Following are the features of first generation computers −  It supported machine language only.  It had slow performance  It occupied large size due to the use of vacuum tubes.  It had a poor storage capacity.  It consumed a lot of electricity and generated a lot of heat.  Malfunction due to overheat  Non-portable Memory: The memory was of 4000 bits. Data Input The input was only provided through hard-wired programs in the computer, mostly through punched cards and paper tapes. Examples The examples of first generation computers are −  ENIAC (Electronic Numeric Integrated And Calculator)  EDVAC  UNIVAC Page 3 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  IBM-701  IBM-650 Second Generation (1955-1964): Several advancements in the first-gen computers led to the development of second generation computers. Following are various changes in features and components of second generation computers − Hardware: The hardware used in the second generation of computers were:  Transistors  Magnetic Tapes Features It had features like −  First operating system was developed - Batch Processing and Multiprogramming Operating System  Faster and smaller in size as compared to first-generation computers  Reliable and energy efficient than the previous generation  Machine language as well as Assembly language was used. Memory The capacity of the memory was 32,000 bits. Data Input The input was provided through punched cards. Examples The examples of second generation computers are −  Honeywell 400  CDC 1604  CDC 3600  IBM 7030  IBM 1401  IBM 1620 Third Generation (1964-1975): Following are the various components and features of the third generation computers − Hardware: Page 4 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams The hardware used in the third generation of computers were  Integrated Circuits made from semi-conductor materials  Large capacity disks and magnetic tapes Features The features of the third generation computers are −  Supports time-sharing OS  Faster, smaller, more reliable and cheaper than the previous generations  Easy to access  High Level Languages were used Memory The capacity of the memory was 128,000 bits. Data Input The input was provided through keyboards and monitors. Examples The examples of third generation computers are −  IBM 360/370  CDC 6600  PDP 8/11 Fourth Generation (1975-1980): Fourth generation computers have the following components and features − Hardware The Hardware used in the fourth generation of computers were −  ICs with Very Large Scale Integration (VLSI) technology  Semiconductor memory  Magnetic tapes and Floppy Features It supports features like −  Multiprocessing & distributed OS  Object-oriented high level programs supported  Small & easy to use; hand-held computers have evolved  No external cooling required & affordable Page 5 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  This generation saw the development of networks and the internet  It saw the development of new trends in GUIs and mouse Memory The capacity of the memory was 100 million bits. Data Input The input was provided through improved hand held devices, keyboard and mouse. Examples The examples of fourth generation computers are −  Apple II  VAX 9000  CRAY 1 (super computers)  CRAY-X-MP(Super Computer) Fifth Generation (1980-Present): These are the modern and advanced computers. Significant changes in the components and operations have made fifth generation computers handy and more reliable than the previous generations. Hardware The Hardware used in the fifth generation of computers are −  Integrated Circuits with ULSI and Nano technology  Large capacity hard disk with RAID support  Powerful servers, Internet, Cluster computing Features It supports features like −  Powerful, cheap, reliable and easy to use.  Portable and faster due to use of parallel processors and Super Large Scale Integrated Circuits.  Introduction of Artificial Intelligence and Expert Systems  Rapid software development is possible.  Can recognize Images and Graphics Memory The capacity of the memory is unlimited. Data Input The input is provided through CDROM, Optical Disk and other touch and voice sensitive input devices. Page 6 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Examples The examples of fifth generation computers are −  IBM  Pentium  PARAM COMPONENTS OF COMPUTERS  The computer is the combination of hardware and software. Hardware is the physical component of a computer like motherboard, memory devices, monitor, keyboard etc., while software is the set of programs or instructions. Both hardware and software together make the computer system to function.  Every task given to a computer follows an Input- Process- Output Cycle (IPO cycle). It needs certain input, processes that input and produces the desired output.  The input unit takes the input, the central processing unit does the processing of data and the output unit produces the output. The memory unit holds the data and instructions during the processing. Components of a computer Input Unit This unit contains devices with the help of which we enter data into the computer. This unit creates a link between the user and the computer. The input devices translate the information into a form understandable by the computer. CPU (Central Processing Unit) CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, intermediate results, and instructions (program). It controls the operation of all parts of the computer.  Central Processing Unit (CPU) consists of the following features −  CPU is considered as the brain of the computer.  CPU performs all types of data processing operations. Page 7 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  It stores data, intermediate results, and instructions (program).  It controls the operation of all parts of the computer. CPU itself has the following three components −  ALU (Arithmetic Logic Unit)  Memory Unit  Control Unit Memory or Storage Unit This unit can store instructions, data, and intermediate results. This unit supplies information to other units of the computer when needed. It is also known as internal storage unit or the main memory or the primary storage or Random Access Memory (RAM). Its size affects speed, power, and capability. Primary memory and secondary memory are two types of memories in the computer. Functions of the memory unit are −  It stores all the data and the instructions required for processing.  It stores intermediate results of processing.  It stores the final results of processing before these results are released to an output device.  All inputs and outputs are transmitted through the main memory. Control Unit This unit controls the operations of all parts of the computer but does not carry out any actual data processing operations. Functions of this unit are −  It is responsible for controlling the transfer of data and instructions among other units of a computer.  It manages and coordinates all the units of the computer.  It obtains the instructions from the memory, interprets them, and directs the operation of the computer.  It communicates with Input/output devices for transfer of data or results from storage.  It does not process or store data. ALU (Arithmetic Logic Unit) This unit consists of two subsections namely,  Arithmetic Section Page 8 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  Logic Section Arithmetic Section Function of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication, and division. All complex operations are done by making repetitive use of the above operations. Logic Section Function of logic section is to perform logic operations such as comparing, selecting, matching, and merging of data. Output Unit The output unit consists of devices with the help of which we get the information from the computer. This unit is a link between the computer and the users. Output devices translate the computer's output into a form understandable by the users. Example: Monitor, Printer etc. INPUT AND OUTPUT DEVICES INPUT DEVICES: An input device is a piece of computer hardware equipment used to provide data and control signals to an information processing system such as a computer or information appliance. Examples of input devices include Keyboards, mouse, scanners, digital cameras, joysticks, Barcode Readers, Light Pen and microphones. Following are some of the important input devices which are used in a computer − Keyboard: The keyboard is a basic input device that is used to enter data into a computer or any other electronic device by pressing keys. It has different sets of keys for letters, numbers, characters, and functions. Keyboards are connected to a computer through USB or a Bluetooth device for wireless communication. Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and Internet. The keys on the keyboard are as follows Keys Description Typing Keys These keys include the letter keys (A-Z) and digit keys (0-9) which generally give the same layout as that of typewriters. Page 9 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Numeric Keypad It is used to enter the numeric data or cursor movement. Generally, it consists of a set of 17 keys that are laid out in the same configuration used by most adding machines and calculators. Function Keys The twelve function keys are present on the keyboard which are arranged in a row at the top of the keyboard. Each function key has a unique meaning and is used for some specific purpose. Control keys These keys provide cursor and screen control. It includes four directional arrow keys. Control keys also include Home, End, Insert, Delete, Page Up, Page Down, Control(Ctrl), Alternate(Alt), Escape(Esc) Special Purpose Keyboard also contains some special purpose keys such as Enter, Shift, Caps Lock, Num Keys Lock, Space bar, Tab, and Print Screen. Mouse: The mouse is a hand-held input device which is used to move cursor or pointer across the screen. It is designed to be used on a flat surface and generally has left and right button and a scroll wheel between them. Laptop computers come with a touchpad that works as a mouse. It lets you control the movement of cursor or pointer by moving your finger over the touchpad. Some mouse comes with integrated features such as extra buttons to perform different buttons. Common types of the mouse: o Trackball Mouse o Mechanical Mouse o Optical Mouse o Cordless or Wireless Mouse Scanner: The scanner uses the pictures and pages of text as input. It scans the picture or a document. The scanned picture or document then converted into a digital format or file and is displayed on the screen as an output. It uses optical character recognition techniques to convert images into digital ones. Some of the common types of scanners are as follows:  Flatbed Scanner  Handheld Scanner  Sheet fed Scanner Page 10 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  Drum Scanner  Photo Scanner Joystick: A joystick is also a pointing input device like a mouse. It is made up of a stick with a spherical base. The base is fitted in a socket that allows free movement of the stick. The movement of stick controls the cursor or pointer on the screen. Light Pen: A light pen is a computer input device that looks like a pen. The tip of the light pen contains a light- sensitive detector that enables the user to point to or select objects on the display screen. Its light sensitive tip detects the object location and sends the corresponding signals to the CPU. Digitizer: Digitizer is a computer input device that has a flat surface and usually comes with a stylus. It enables the user to draw images and graphics using the stylus as we draw on paper with a pencil. The images or graphics drawn on the digitizer appear on the computer monitor or display screen. The software converts the touch inputs into lines and can also convert handwritten text to typewritten words. Microphone: The microphone is a computer input device that is used to input the sound. It receives the sound vibrations and converts them into audio signals or sends to a recording medium. The audio signals are converted into digital data and stored in the computer. Magnetic Ink Character Recognition (MICR): MICR computer input device is designed to read the text printed with magnetic ink. MICR is a character recognition technology that makes use of special magnetized ink which is sensitive to magnetic fields. It is widely used in banks to process the cheques and other organizations where security is a major concern. Optical Character Reader (OCR): OCR computer input device is designed to convert the scanned images of handwritten, typed or printed text into digital text. It is widely used in offices and libraries to convert documents and books into electronic files. Bar Code Readers: Bar Code Reader is a device used for reading bar coded data (data in the form of light and dark lines). Bar coded data is generally used in labelling goods, numbering the books, etc. It may be a handheld scanner or may be embedded in a stationary scanner Page 11 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Optical Mark Reader (OMR): OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked. OUTPUT DEVICES: The output device displays the result of the processing of raw data that is entered in the computer through an input device. There are a number of output devices that display output in different ways such as text, images, hard copies, and audio or video. Following are some of the important output devices used in a computer.  Monitors  Graphic Plotter  Printer  Projector Monitor: Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels. There are two kinds of viewing screen used for monitors.  Cathode-Ray Tube (CRT)  Flat-Panel Display Cathode-Ray Tube (CRT) Monitor: Page 12 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity or resolution. It takes more than one illuminated pixel to form a whole character, such as the letter „e‟ in the word help. A finite number of characters can be displayed on a screen at once. The screen can be divided into a series of character boxes - fixed location on the screen where a standard character can be placed. Most screens are capable of displaying 80 characters of data horizontally and 25 lines vertically. There are some disadvantages of CRT − o Large in Size o High power consumption Flat-Panel Display Monitor: The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT. You can hang them on walls or wear them on your wrists. Current uses of flat-panel displays include calculators, video games, monitors, laptop computer, and graphics display. The flat-panel display is divided into two categories –  Emissive Displays: Emissive displays are devices that convert electrical energy into light. For example, plasma panel and LED (Light-Emitting Diodes). Page 13 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  Non-Emissive Displays: Non-emissive displays use optical effects to convert sunlight or light from some other source into graphics patterns. For example, LCD (Liquid-Crystal Device). Printer: A printer produces hard copies of the processed data. It enables the user, to print images, text or any other information onto the paper. Based on the printing mechanism, the printers are of two types: Impact Printers and Non-impact Printers. 1. Impact Printers: They are of two types:  Character Printers  Dot Matrix printers  Daisy Wheel printers  Line printers  Drum printers  Chain printers 2. Non-impact printers: They are of two types:  Laser printers  Inkjet printers Projector: A projector is an output device that enables the user to project the output onto a large surface such as a big screen or wall. It can be connected to a computer and similar devices to project their output onto a screen. It uses light and lenses to produce magnified texts, images, and videos. So, it is an ideal output device to give presentations or to teach a large number of people. Computer Memory Memory is the best essential element of a computer because computer can‟t perform simple tasks. The performance of computer mainly based on memory and CPU. Memory is internal storage media of computer that has several names such as majorly categorized into two types, 1. Main memory/ Primary Memory 2. Secondary Memory Page 14 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Primary Memory: Primary memory is computer memory that a processor or computer accesses first or directly. It allows a processor to access running execution applications and services that are temporarily stored in a specific memory location. Primary memory is also known as primary storage or main memory 1. RAM (Volatile Memory). 2. ROM (Non-Volatile Memory). Random Access Memory (RAM): It is a volatile memory. It means it does not store data or instructions permanently. It is read/write memory which stores data till the machine is working. When you switch on the computer and perform some task the data and instructions from the hard disk are stored in RAM. CPU utilizes this data to perform the required tasks. As soon as you shut down the computer the RAM loses all the data. RAM categorized into following types. 1. DRAM- Dynamic memory must be constantly refreshed, or it loses its contents. This type of memory is more economical. 2. SRAM- SRAM is faster and less volatile than DRAM but requires more power and is more expensive. It does not need to be refreshed like a DRAM. 3. SDRAM(Synchronous Dynamic Random-Access Memory) - A type of DRAM that can run at much higher clock speeds. Read Only Memory (ROM): Page 15 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams It is a non-volatile memory. It means it does not lose its data or programs that are written on it at the time of manufacture. So it is a permanent memory that contains all important data and instructions needed to perform important tasks like the boot process. ROM memory has several models such names are following. 1. PROM: Programmable Read Only Memory (PROM) maintains large storage media but can’t offer the erase features in ROM. This type of RO maintains PROM chips to write data once and read many. The programs or instructions designed in PROM can‟t be erased by other programs. 2. EPROM : Erasable Programmable Read Only Memory designed for recover the problems of PROM and ROM. Users can delete the data of EPROM thorough pass on ultraviolet light and it erases chip is reprogrammed. 3. EEPROM: Electrically Erasable Programmable Read Only Memory similar to the EPROM but it uses electrical beam for erase the data of ROM. Some other memories are  Register Memory: Register memory is the smallest and fastest memory in a computer. It is located in the CPU in the form of registers. A register temporarily holds frequently used data, instructions and memory address that can be quickly accessed by the CPU.  Cache Memory: It is small in size but faster than the main memory. The CPU can access it more quickly than the primary memory. It holds the data and programs frequently used by the CPU. So if the CPU finds the required data or instructions in cache memory it doesn't need to access the primary memory (RAM). Thus, it speeds up the system performance.  Semi-volatile memory: A third category of memory is "semi-volatile". The term is used to describe a memory which has some limited non- volatile duration after power is removed, but then data is ultimately lost. A typical goal when using a semi-volatile memory is to provide high performance/durability/etc. associated with volatile memories, while providing some benefits of a true non-volatile memory.  Virtual memory: Virtual memory is a system where all physical memory is controlled by the operating system. When a program needs memory, it requests it from the operating system. The operating system then decides in what physical location to place the program's code and data.  Protected memory: Page 16 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Protected memory is a system where each program is given an area of memory to use and is not permitted to go outside that range. Use of protected memory greatly enhances both the reliability and security of a computer system. Secondary Memory: The storage devices in the computer or connected to the computer are known as secondary memory of the computer. It is non-volatile in nature so permanently stores the data even when the computer is turned off. The CPU can't directly access the secondary memory. First the secondary memory data is transferred to primary memory then CPU can access it. Common secondary storage devices are the hard disk and optical disks. The hard disk has enormous storage capacity compared to main memory. There are three main types of secondary storage in a computer system:  Solid state storage devices (such as USB memory sticks): Solid state storage is also faster than traditional hard disk drives because the data is stored electrically in silicon chips called cells. Within the cells, the binary data is stored by holding an electrical current in a transistor with an on / off mode.  Optical storage devices (such as CD, DVD and Blue-ray discs): Optical devices use a laser to scan the surface of a spinning disc made from metal and plastic. The disc surface is divided into tracks, with each track containing many flat areas and hollows. The flat areas are known as lands and the hollows as pits.  Magnetic storage devices (such as hard disk drives): Magnetic devices such as hard disk drives use magnetic fields to magnetise tiny individual sections of a metal spinning disk. Each tiny section represents one bit. A magnetised section represents a binary '1' and a demagnetized section represents a binary '0'. Hard drive: It is a non-removable storage device containing magnetic disks or platters rotating at high speeds. The hard drives store data in segments of concentric circles. It may spin at 5,400 to 15,000 RPM. Optical disk: an electronic data storage medium that can be written to and read using a low-powered laser beam.  CD-ROM: "Read only" (used for distribution of commercial software, for example) Standard storage capacity is 640MB.  CD-R (or CD-WORM): "Write Once, Read Many" times  CD-RW: rewritable multiple times  DVD: similar to CD, but with significantly larger storage capacity (4.7GB)  Write once read many (WORM) describes a data storage device in which information, once written, cannot be modified Floppy Disk: Floppy disk is composed of a thin, flexible magnetic disk sealed in a square plastic carrier. Floppy disks were widely used to distribute software, transfer files, and create backup copies of data. To read and write data from a floppy disk, a computer system must have a floppy disk drive (FDD). Magnetic Tape: Magnetic tape used in recording sound, pictures, or computer data. Page 17 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Flash memory: a kind of memory that retains data in the absence of a power supply. Primary memory Secondary memory The primary memory is categorized as volatile The secondary memory is always a non- & nonvolatile memories. volatile memory. These memories are also called internal Secondary memory is known as a Backup memory. memory or Additional memory or Auxiliary memory. Data is directly accessed by the processing Data cannot be accessed directly by the unit. processor. It is first copied from secondary memory to primary memory. Only then CPU can access it. It holds data or information that is currently It stores a substantial amount of data and being used by the processing unit. Capacity is information. Capacity is generally from 200GB usually in 16 to 32 GB to terabytes. Primary memory can be accessed by the data Secondary memory is accessed by I/O bus. channels. Primary memory is costlier than secondary Secondary memory is cheaper than primary memory. memory. Memory unit Memory unit is the amount of data that can be stored in the storage unit. This storage capacity is expressed in terms of Bytes. Unit Description Bit (Binary Digit) A binary digit is logical 0 and 1 representing a passive or an active state of a component in an electric circuit. Nibble A group of 4 bits is called nibble. Byte A group of 8 bits is called byte. A byte is the smallest unit, which can represent a data item or a character. Kilobyte (KB) 1 KB = 1024 Bytes Megabyte (MB) 1 MB = 1024 KB GigaByte (GB) 1 GB = 1024 MB TeraByte (TB) 1 TB = 1024 GB Page 18 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams PetaByte (PB) 1 PB = 1024 TB Exa Byte 1 EB = 1024 PB Zetta Byte 1 ZB = 1024 EB Yotta Byte 1 YB = 1024 ZB Programming Languages The computer system is simply a machine and hence it cannot perform any work; therefore, in order to make it functional different languages are developed, which are known as programming languages or simply computer languages. Languages comes with its own set of vocabulary and rules, better known as syntax Following are the major categories of Programming Languages − 1. Machine Language 2. Assembly Language 3. High Level Language 4. System Language 5. Scripting Language Machine Language or Code This is the language that is written for the computer hardware. Such language is effected directly by the central processing unit (CPU) of a computer system. Assembly Language It is a language of an encoding of machine code that makes simpler and readable. High Level Language The high level language is simple and easy to understand and it is similar to English language. For example, COBOL, FORTRAN, BASIC, C, C+, Python, etc. Computer Network Types A computer network is a group of computers linked to each other that enables the computer to communicate with another computer and share their resources, data, and applications. Page 19 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams A computer network can be categorized by their size. A computer network is mainly of four types:  LAN(Local Area Network)  PAN(Personal Area Network)  MAN(Metropolitan Area Network)  WAN(Wide Area Network) LAN (Local Area Network):  Local Area Network is a group of computers connected to each other in a small area such as building, office.  LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc.  It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and ethernet cables.  The data is transferred at an extremely faster rate in Local Area Network. PAN (Personal Area Network):  Personal Area Network is a network arranged within an individual person, typically within a range of 10 meters.  Personal Area Network is used for connecting the computer devices of personal use is known as Personal Area Network.  Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network.  Personal Area Network covers an area of 30 feet.  Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media player and play stations. There are two types of Personal Area Network:  Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as WiFi, Bluetooth. It is a low range network.  Wired Personal Area Network: Wired Personal Area Network is created by using the USB MAN (Metropolitan Area Network):  A metropolitan area network is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network.  Government agencies use MAN to connect to the citizens and private industries. WAN (Wide Area Network):  A Wide Area Network is a network that extends over a large geographical area such as states or countries. Page 20 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  A Wide Area Network is quite bigger network than the LAN.  A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fibre optic cable or satellite links.  The internet is one of the biggest WAN in the world.  A Wide Area Network is widely used in the field of Business, government, and education. Internetwork:  An internetwork is defined as two or more computer network LANs or WAN or computer network segments are connected using devices, and they are configured by a local addressing scheme. This process is known as internetworking.  An interconnection between public, private, commercial, industrial, or government computer networks can also be defined as internetworking.  An internetworking uses the internet protocol.  The reference model used for internetworking is Open System Interconnection (OSI). Types of Internetwork:  Extranet: An extranet is a communication network based on the internet protocol such as Transmission Control protocol and internet protocol.  Intranet: An intranet is a private network based on the internet protocol such as Transmission Control protocol and internet protocol. Logic gates and Boolean operations Logic Gates: The logic gates are the main structural part of a digital system.  Logic Gates are a block of hardware that produces signals of binary 1 or 0 when input logic requirements are satisfied.  Each gate has a distinct graphic symbol, and its operation can be described by means of algebraic expressions.  The seven basic logic gates includes: AND, OR, XOR, NOT, NAND, NOR, and XNOR.  The relationship between the input-output binary variables for each gate can be represented in tabular form by a truth table.  Each gate has one or two binary input variables designated by A and B and one binary output variable designated by x. AND GATE: Page 21 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams The AND gate is an electronic circuit which gives a high output only if all its inputs are high. The AND operation is represented by a dot (.) sign. OR GATE: The OR gate is an electronic circuit which gives a high output if one or more of its inputs are high. The operation performed by an OR gate is represented by a plus (+) sign. NOT GATE: The NOT gate is an electronic circuit which produces an inverted version of the input at its output. It is also known as an Inverter. NAND GATE: Page 22 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams The NOT-AND (NAND) gate which is equal to an AND gate followed by a NOT gate. The NAND gate gives a high output if any of the inputs are low. The NAND gate is represented by a AND gate with a small circle on the output. The small circle represents inversion. NOR GATE: The NOT-OR (NOR) gate which is equal to an OR gate followed by a NOT gate. The NOR gate gives a low output if any of the inputs are high. The NOR gate is represented by an OR gate with a small circle on the output. The small circle represents inversion. Exclusive-OR/ XOR GATE: The 'Exclusive-OR' gate is a circuit which will give a high output if one of its inputs is high but not both of them. The XOR operation is represented by an encircled plus sign. Page 23 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams EXCLUSIVE-NOR/Equivalence GATE: The 'Exclusive-NOR' gate is a circuit that does the inverse operation to the XOR gate. It will give a low output if one of its inputs is high but not both of them. The small circle represents inversion. Boolean algebra Boolean algebra can be considered as an algebra that deals with binary variables and logic operations. Boolean algebraic variables are designated by letters such as A, B, x, and y. The basic operations performed are AND, OR, and complement. The Boolean algebraic functions are mostly expressed with binary variables, logic operation symbols, parentheses, and equal sign. For a given value of variables, the Boolean function can be either 1 or 0. Number System When we type some letters or words, the computer translates them in numbers as computers can understand only numbers. A computer can understand the positional number system where there are only a few symbols called digits and these symbols represent different values depending on the position they occupy in the number. Page 24 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams The value of each digit in a number can be determined using −  The digit  The position of the digit in the number  The base of the number system (where the base is defined as the total number of digits available in the number system) Decimal Number System: The number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands, and so on. S.No. Number System and Description 1 Binary Number System Base 2. Digits used : 0, 1 2 Octal Number System Base 8. Digits used : 0 to 7 3 Hexa Decimal Number System Base 16. Digits used: 0 to 9, Letters used : A- F Binary Number System Characteristics of the binary number system are as follows −  Uses two digits, 0 and 1  Also called as base 2 number system  Each position in a binary number represents a 0 power of the base (2). Example 20  Last position in a binary number represents a x power of the base (2). Example 2x where x represents the last position - 1. Octal Number System: Characteristics of the octal number system are as follows −  Uses eight digits, 0,1,2,3,4,5,6,7  Also called as base 8 number system Page 25 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams  Each position in an octal number represents a 0 power of the base (8). Example 80  Last position in an octal number represents a x power of the base (8). Example 8x where x represents the last position – 1 Hexadecimal Number System: Characteristics of hexadecimal number system are as follows −  Uses 10 digits and 6 letters, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F  Letters represent the numbers starting from 10. A = 10. B = 11, C = 12, D = 13, E = 14, F = 15  Also called as base 16 number system  Each position in a hexadecimal number represents a 0 power of the base (16). Example, 160  Last position in a hexadecimal number represents a x power of the base (16). Example 16x where x represents the last position – 1 COMPUTER SECURITY Computer security, cyber-security or information technology security (IT security) is the protection of computer systems from the theft of or damage to their hardware, software, or electronic data, as well as from the disruption or misdirection of the services they provide. Internet security is a branch of computer security specifically related to not only Internet, often involving browser security and the World Wide Web. Its objective is to establish rules and measures to use against attacks over the Internet. The Internet represents an insecure channel for exchanging information, which leads to a high risk of intrusion or fraud, such as phishing, online viruses, Trojans, worms and more. Many methods are used to protect the transfer of data, including encryption and from-the-ground-up engineering. Types of attacks: A cyber-attack is an exploitation of computer systems and networks. It uses malicious code to alter computer code, logic or data and lead to cybercrimes, such as information and identity theft. Attacks can be classified into the following categories: 1. Web-based attacks 2. System-based attacks Page 26 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Web-based attacks These are the attacks which occur on a website or web applications. Some of the important web-based attacks are as follows- Injection attacks It is the attack in which some data will be injected into a web application to manipulate the application and fetch the required information. Example- SQL Injection, code Injection; log Injection, XML Injection etc. DNS Spoofing DNS spoofing is a type of computer security hacking. Whereby a data is introduced into a DNS resolver's cache causing the name server to return an incorrect IP address, diverting traffic to the attacker‟s computer or any other computer. The DNS spoofing attacks can go on for a long period of time without being detected and can cause serious security issues. Session Hijacking It is a security attack on a user session over a protected network. Web applications create cookies to store the state and user sessions. By stealing the cookies, an attacker can have access to all of the user data. Phishing Phishing is a type of attack which attempts to steal sensitive information like user login credentials and credit card number. It occurs when an attacker is masquerading as a trustworthy entity in electronic communication. Brute force It is a type of attack which uses a trial and error method. This attack generates a large number of guesses and validates them to obtain actual data like user password and personal identification number. This attack may be used by criminals to crack encrypted data, or by security, analysts to test an organization's network security. Denial of Service It is an attack which meant to make a server or network resource unavailable to the users. It accomplishes this by flooding the target with traffic or sending it information that triggers a crash. It uses the single system and single internet connection to attack a server. It can be classified into the following-  Volume-based attacks- Its goal is to saturate the bandwidth of the attacked site, and is measured in bit per second.  Protocol attacks- It consumes actual server resources, and is measured in a packet.  Application layer attacks- Its goal is to crash the web server and is measured in request per second. Page 27 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Dictionary attacks This type of attack stored the list of a commonly used password and validated them to get original password. URL Interpretation It is a type of attack where we can change the certain parts of a URL, and one can make a web server to deliver web pages for which he is not authorized to browse. File Inclusion attacks It is a type of attack that allows an attacker to access unauthorized or essential files which is available on the web server or to execute malicious files on the web server by making use of the include functionality. Man in the middle attacks It is a type of attack that allows an attacker to intercepts the connection between client and server and acts as a bridge between them. Due to this, an attacker will be able to read, insert and modify the data in the intercepted connection. System-based attacks These are the attacks which are intended to compromise a computer or a computer network. Some of the important system-based attacks are as follows- 1. Virus: A computer virus is a type of malicious software that, when executed, replicates itself by modifying other computer programs and inserting its own code. When this replication succeeds, the affected areas are then said to be "infected" with a computer virus. A virus can be spread by opening an email attachment, clicking on an executable file, visiting an infected website or viewing an infected website advertisement. It can also be spread through infected removable storage devices, such USB drives. Once a virus has infected the host it has the capacity to corrupt or to delete data on your computer and it can utilize an email program to spread the virus to other computer systems.In the worst case scenario, it can even delete everything on your hard disk.The purpose of it is to disrupt the operation of the computer or the program. Ripper, Stuxnet, Petya, Wanna cry, Code red, Melissa, Sasser, Zeus, Mydoom, Crypto Locker, Flashback are some example of Viruses. 2. Computer Worm: A computer worm is a malicious, self-replicating software program (malware) which affects the functions of software and hardware programs. Page 28 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Before widespread use of networks, computer worms were spread through infected storage media, such as floppy diskettes, which, when mounted on a system, would infect other storage devices connected to the victim system. USB drives are still a common vector for computer worms. Differences between worms and viruses: Computer worms "are self-replicating programs that spread with no human intervention after they are started." In contrast, "viruses are also self-replicating programs, but usually require some action on the part of the user to spread inadvertently to other programs or systems." 3. Trojan horse: Trojan horse or Trojan is any malware which misleads users of its true intent. Trojans are generally spread by some form of social engineering, for example where a user is duped into executing an e-mail attachment disguised to appear not suspicious, (e.g., a routine form to be filled in), or by clicking on some fake advertisement on social media or anywhere else. Trojans may allow an attacker to access users' personal information such as banking information, passwords, or personal identity. It can also delete a user's files or infect other devices connected to the network. Ransomware attacks are often carried out using a Trojan. After it is activated, it can achieve any number of attacks on the host, from irritating the user (popping up windows or changing desktops) to damaging the host (deleting files, stealing data, or activating and spreading other malware, such as viruses). Trojans are also known to create backdoors to give malicious users access to the system. Unlike computer viruses and worms, Trojans generally do not attempt to inject themselves into other files or otherwise propagate themselves. 4. Malware: Short for malicious software, is any software used to disrupt computer operation, gather sensitive information, or gain access to private computer systems. It can appear in the form of executable code, scripts, active content, and other software. 5. Ransomware: Ransomware is a type of malware program that infects and takes control of a system. It infects a computer with the intention of extorting money from its owner. 6. Spyware: Spyware is unwanted software that infiltrates your computing device, stealing your internet usage data and sensitive information. Spyware is classified as a type of malware designed to gain access to or damage your computer, often without your knowledge. Just like viruses, spyware can be installed when you open an e-mail attachment Page 29 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams containing the malicious software or through cookies. It can also be installed when you install another program that has a spyware installer attached to it. 7. Adware: Adware, or advertising-supported software, is software that generates revenue for its developer by automatically generating online advertisements in the user interface of the software or on a screen presented to the user during the installation process. The software may generate two types of revenue: one is for the display of the advertisement and another on a "pay-per-click" basis, if the user clicks on the advertisement. The software may implement advertisements in a variety of ways, including a static box display, a banner display, full screen, a video, pop-up ad or in some other form. 8. Key logger: A key logger is a type of malware that stores all keystrokes of a computer. It can record all sorts of personal information, such as usernames, passwords, credit card numbers, and personal documents such as emails and reports. 9. Phishing: Phishing is the fraudulent attempt to obtain access credentials such as usernames, passwords and credit card details by disguising oneself as a trustworthy entity in an electronic communication. Typically carried out by email spoofing or instant messaging,it often directs users to enter personal information at a fake website which matches the look and feel of the legitimate site. 10. Spoofing: A Spoofing attack is a situation in which one person or program successfully represents oneself as another by falsifying data and thereby gaining an illegitimate advantage. 11. Pharming: Pharming is a cyber-attack intended to redirect a website's traffic to another, fake site. Pharming can be conducted either by changing the hosts file on a victim's computer or by exploitation of a vulnerability in DNS server software. DNS servers are computers responsible for resolving Internet names into their real IP addresses. User of online banking and e-commerce websites are more prone to this attack. IMPORTANT TERMS: 1. Anti-virus software is a program or set of programs that are designed to prevent, search for, detect, and remove software viruses, and other malicious software like worms, trojans, and adware. 2. Firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules Page 30 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams 3. Authorization is the function of specifying access rights to resources related to information security and computer security in general and to access control in particular. More formally, "to authorize" is to define an access policy. 4. Authentication is the act of confirming the truth of an attribute of a single piece of data or entity. It might involve confirming the identity of a person by validating their identity documents, verifying the validity of a website with a digital certificate, tracing the age of an artifact by carbon dating, or ensuring that a product is what its packaging and labeling claim to be. In other words, Authentication often involves verifying the validity of at least one form of identification. 5. A person who uses his or her expertise to gain access to other people‟s computers to get information illegally or do damage is a Hacker. 6. Zombie is a computer connected to the Internet that has been compromised by a hacker, computer virus or trojan horse program and can be used to perform malicious tasks of one sort or another under remote direction. 7. Breach is the moment a hacker successfully exploits vulnerability in a computer or device, and gains access to its files and network. 8. Bot/Botnet is a type of software application or script that performs tasks on command, allowing an attacker to take complete control remotely of an affected computer. A collection of these infected computers is known as a “botnet” and is controlled by the hacker or “bot-herder”. 9. Spam is unwanted emails. In other words we can call them as unsolicited promotional mail. 10. Encryption is the method by which plaintext or any other type of data is converted from a readable form to an encoded version that can only be decoded by another entity if they have access to a decryption key. Encryption is one of the most important methods for providing data security, especially for end-to-end protection of data transmitted across networks. SHORTCUT KEYS KEYBOARD SHORTCUTS: Shortcut keys Description Alt + F File menu options in current program Alt + E Edit options in current program Ctrl +A Select all text Ctrl + F Find Ctrl +X Cut selected item Shift + Del Delete permanently Ctrl + C Copy selected item Ctrl + Insert Copy selected item Page 31 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Ctrl + V Paste Shift + Insert Paste Home Go to beginning of current line Ctrl + Home Go to beginning of document End Go to end of current line Ctrl + End Go to end of document Shift + Home Highlight from current position to beginning of line Shift + End Highlight from current position to end of line Ctrl + Move one word to the right at a time MICROSOFT WORD Shortcut Description Ctrl+0 Toggles 6pts of spacing before a paragraph. Ctrl+A Select all contents of the page. Ctrl+B Bold highlighted selection. Ctrl+C Copy selected text. Ctrl+D Open the font preferences window. Ctrl+E Aligns the line or selected text to the center of the screen. Ctrl+F Open find box. Ctrl+I Italic highlighted selection. Ctrl+J Aligns the selected text or line to justify the screen. Ctrl+K Insert a hyperlink. Ctrl+L Aligns the line or selected text to the left of the screen. Ctrl+M Indent the paragraph. Ctrl+N Opens new, blank document window. Page 32 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Ctrl+O Opens the dialog box or page for selecting a file to open. Ctrl+P Open the print window. Ctrl+R Aligns the line or selected text to the right of the screen. Ctrl+S Save the open document. Like Shift+F12. Alt, F, A Save the document under a different file name. Ctrl+T Create a hanging indent. Ctrl+U Underline the selected text. Ctrl+V Paste. Ctrl+W Close the currently open document. Ctrl+X Cut selected text. Ctrl+Y Redo the last action performed. Ctrl+Z Undo last action. Ctrl+Shift+L Quickly create a bullet point. Ctrl+Shift+F Change the font. Ctrl+Shift+> Increase selected font +1pts up to 12pt and then increase font +2pts. Ctrl+] Increase selected font +1pts. Ctrl+Shift+< Decrease selected font -1pts if 12pt or lower; if above 12, decreases font by +2pt. Ctrl+[ Decrease selected font -1pts. Ctrl+/+c Insert a cent sign (¢). Ctrl+'+ Insert a character with an accent (grave) mark, where is the character you want. For example, if you wanted an accented è you would Page 33 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams use Ctrl+'+e as your shortcut key. To reverse the accent mark use the opposite accent mark, often on the tilde key. Ctrl+Shift+* View or hide non printing characters. Ctrl+ Moves one word to the left. Ctrl+ Moves one word to the right. Ctrl+ Moves to the beginning of the line or paragraph. Ctrl+ Moves to the end of the paragraph. Ctrl+Del Deletes word to right of cursor. Ctrl+Backspace Deletes word to left of cursor. Ctrl+End Moves the cursor to the end of the document. Ctrl+Home Moves the cursor to the beginning of the document. Ctrl+Spacebar Reset highlighted text to the default font. Ctrl+1 Single-space lines. Ctrl+2 Double-space lines. Ctrl+5 1.5-line spacing. Ctrl+Alt+1 Changes text to heading 1. Ctrl+Alt+2 Changes text to heading 2. Ctrl+Alt+3 Changes text to heading 3. Alt+Ctrl+F2 Open new document. Ctrl+F1 Open the Task Pane. Ctrl+F2 Display the print preview. Ctrl+Shift+> Increases the selected text size by one font size. Page 34 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Ctrl+Shift+< Decreases the selected text size by one font size. Ctrl+Shift+F6 Switches to another open Microsoft Word document. Ctrl+Shift+F12 Prints the document. F1 Open help. F4 Repeat the last action performed (Word 2000+). F5 Open the Find, Replace, and Go To window in Microsoft Word. F7 Spellcheck and grammar check selected text or document. F12 Save As. Shift+F3 Change the text in Microsoft Word from uppercase to lowercase or a capital letter at the beginning of every word. Shift+F7 Runs a Thesaurus check on the selected word. Shift+F12 Save the open document. Like Ctrl+S. Shift+Enter Create a soft break instead of a new paragraph. Shift+Insert Paste. Shift+Alt+D Insert the current date. Shift+Alt+T Insert the current time. EXCEL: Shortcut Description Tab Move to the next cell, to the right of the currently selected cell. Ctrl+A Select all contents of a worksheet. Ctrl+B Bold all cells in the highlighted section. Page 35 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Ctrl+C Copy all cells in the highlighted section. Ctrl+D Fill down. Fills the cell beneath with the contents of the selected cell. To fill more than one cell, select the source cell and press Ctrl+Shift+Downto select multiple cells. Then press Ctrl+D to fill them with the contents of the original cell. Ctrl+F Search current sheet. Ctrl+G Go to a certain area. Ctrl+H Find and replace. Ctrl+I Puts italics on all cells in the highlighted section. Ctrl+K Inserts a hyperlink. Ctrl+N Creates a new workbook. Ctrl+O Opens a workbook. Ctrl+P Print the current sheet. Ctrl+R Fill right. Fills the cell to the right with the contents of the selected cell. To fill more than one cell, select the source cell and press Ctrl+Shift+Rightto select multiple cells. Then press Ctrl+R to fill them with the contents of the original cell. Ctrl+S Saves the open worksheet. Ctrl+U Underlines all cells in the highlighted section. Ctrl+V Pastes everything copied onto the clipboard. Ctrl+W Closes the current workbook. Ctrl+X Cuts all cells in the highlighted section. Page 36 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Ctrl+Y Repeats the last entry. Ctrl+Z Undo the last action. Ctrl+1 Changes the format of the selected cells. Ctrl+2 Bolds all cells in the highlighted section. Ctrl+3 Puts italics all cells in the highlighted section. Ctrl+4 Underlines all cells in highlighted section. Ctrl+5 Puts a strikethrough all cells in the highlighted section. Ctrl+6 Shows or hides objects. Ctrl+7 Shows or hides the toolbar. Ctrl+8 Toggles the outline symbols. Ctrl+9 Hides rows. Ctrl+0 Hides columns. Ctrl+Shift+: Enters the current time. Ctrl+; Enters the current date. Ctrl+` Changes between displaying cell values or formulas in the worksheet. Ctrl+' Copies a formula from the cell above. Ctrl+Shift+" Copies value from cell above. Ctrl+- Deletes the selected column or row. Ctrl+Shift+= Inserts a new column or row. Ctrl+Shift+~ Switches between showing Excel formulas or their values in cells. Ctrl+Shift+@ Applies time formatting. Page 37 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Ctrl+Shift+! Applies comma formatting. Ctrl+Shift+$ Applies currency formatting. Ctrl+Shift+# Applies date formatting. Ctrl+Shift+% Applies percentage formatting. Ctrl+Shift+^ Applies exponential formatting. Ctrl+Shift+* Selects the current region around the active cell. Ctrl+Shift+& Places border around selected cells. Ctrl+Shift+_ Removes a border. Ctrl++ Insert. Ctrl+- Delete. Ctrl+Shift+( Unhide rows. Ctrl+Shift+) Unhide columns. Ctrl+/ Selects the array containing the active cell. Ctrl+\ Selects the cells that have a static value or don‟t match the formula in the active cell. Ctrl+[ Selects all cells referenced by formulas in the highlighted section. Ctrl+] Selects cells that contain formulas that reference the active cell. Ctrl+Shift+{ Selects all cells directly or indirectly referenced by formulas in the highlighted section. Ctrl+Shift+} Selects cells which contain formulas that directly or indirectly reference the active cell. Ctrl+Shift+| (pipe) Selects the cells within a column that don‟t match the formula or Page 38 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams static value in the active cell. Ctrl+Enter Fills the selected cells with the current entry. Ctrl+Spacebar Selects the entire column. Ctrl+Shift+Spacebar Selects the entire worksheet. Ctrl+Home Move to cell A1. Ctrl+End Move to last cell on worksheet. Ctrl+Tab Move between Two or more open Excel files. Ctrl+Shift+Tab Activates the previous workbook. Ctrl+Shift+A Inserts argument names into a formula. Ctrl+Shift+F Opens the drop-down menu for fonts. Ctrl+Shift+O Selects all of the cells that contain comments. Ctrl+Shift+P Opens the drop-down menu for point size. Shift+Insert Pastes what is stored on the clipboard. Shift+Page Up In a single column, highlights all cells above that are selected. Shift+Page Down In a single column, highlights all cells above that are selected. Shift+Home Highlights all text to the left of the cursor. Shift+End Highlights all text to the right of the cursor. Shift+Up Arrow Extends the highlighted area up one cell. Shift+Down Arrow Extends the highlighted area down one cell. Shift+Left Arrow Extends the highlighted area left one character. Shift +Right Arrow Extends the highlighted area right one character. Alt+Tab Cycles through applications. Page 39 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Alt+Spacebar Opens the system menu. Alt+Backspace Undo. Alt+Enter While typing text in a cell, pressing Alt+Enter moves to the next line, allowing for multiple lines of text in one cell. Alt+= Creates a formula to sum all of the above cells. Alt+' Allows formatting on a dialog box. F1 Opens the help menu. F2 Edits the selected cell. F3 After a name is created, F3 will paste names. F4 Repeats last action. For example, if you changed the color of text in another cell, pressing F4 will change the text in cell to the same color. F5 Goes to a specific cell. For example, C6. F6 Move to the next pane. F7 Spell check selected text or document. F8 Enters Extend Mode. F9 Recalculates every workbook. F10 Activates the menu bar. F11 Creates a chart from selected data. F12 Save As option. Shift+F1 Opens the "What's This?" window. Shift+F2 Allows the user to edit a cell comment. Page 40 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Shift+F3 Opens the Excel formula window. Shift+F5 Brings up a search box. Shift+F6 Move to previous pane. Shift+F8 Add to selection. Shift+F9 Performs calculate function on active sheet. Ctrl+F3 Open Excel Name Manager. Ctrl+F4 Closes current Window. Ctrl+F5 Restores window size. Ctrl+F6 Next workbook. Ctrl+Shift+F6 Previous workbook. Ctrl+F7 Moves the window. Ctrl+F8 Resizes the window. Ctrl+F9 Minimize current window. Ctrl+F10 Maximize currently selected window. Ctrl+F11 Inserts a macro sheet. Ctrl+F12 Opens a file. Ctrl+Shift+F3 Creates names by using those of either row or column labels. Ctrl+Shift+F6 Moves to the previous worksheet window. Ctrl+Shift+F12 Prints the current worksheet. Alt+F1 Inserts a chart. Alt+F2 Save As option. Alt+F4 Exits Excel. Page 41 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Alt+F8 Opens the macro dialog box. Alt+F11 Opens the Visual Basic editor. Alt+Shift+F1 Creates a new worksheet. Alt+Shift+F2 Saves the current worksheet. POWER POINT: Shortcut keys Description Alt + W View Tab Alt + G Design Tab Alt + R Review Tab Alt + Q Search Ctrl + F5 Restore window to previous Size Shift + F10 Display context menu Shift + F6 Move anticlockwise among Pane Ctrl + Shift + Z Normal/Plain Text Shift + F3 Toggle cases Ctrl + Shift + F Change Font Style Ctrl + D Duplicate slide Alt + F10 Maximize window Alt + N, W Insert word art Alt + N, X Insert textbox Alt + W, Q Change the zoom Alt + H, F and S Change the font Size Alt + H, S and H Insert a shape Alt + G, H Select a theme Alt + H, L Select a slide layout Alt + N, P Insert a picture Page 42 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Alt + H Home Tab Alt + N Insert tab Alt + S, B Start Slideshow Alt + F, X Close PowerPoint Esc End the slideshow Alt + T Transitions Tab Alt + A Animation Tab F5 Slide Show Definitions and terminologies Application: An application is a set of codes designed to allow specific tasks to happen. Microsoft Windows and Internet Explorer are common examples. Access time: The performance of a hard drive or other storage device - how long it takes to locate a file. Active program or window: The application or window at the front (foreground) on the monitor. ALGOL: It was the first language with a formal grammar. ALGOL was created by a committee for scientific use in 1958. Its major contribution is being the root of the tree that has led to such languages as Pascal, C, C+ + and Java. Algorithm: In computing, an algorithm is a procedure for accomplishing some tasks which, given an initial state, will terminate in a defined end-state. ASCII (pronounced ask key): American Standard Code for Information Interchange. a commonly used data format for exchanging information between computers or programs. Amplifier: A device that takes in a weak electric signal and sends out a strong one. It is used to boost electrical Signals in many electronic devices such as radios, !elevisions and telephone. Analog Computer: A computer that operates on data which is in the form of continuous variable physical quantities. Android: It is a linux based operating system designed Primarily for touchscreen mobile devices such as smartphones and tablets computer. Antivirus Software: Antivirus software consists of 3omputer programs that attempt to identify threat and eliminate computer virus and other malicious software ( Malware ) API: API refers to Application Programming Interface. It‟s the platform used by a program to access different services on the computer system. Page 43 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Application Software: Application software is a subclass of computer software that employs the capabilities of a computer directly to a task that the user wishes to perform. e.g., word document, spreadsheet, etc. Archieve: It provides backup storage. Arithmetic Logic Unit (ALU): The arithmetic logic unit is a part of the execution unit, a core component of all CPUs. ALUs are capable of calculating the results of a wide variety of basic arithmetical and logical computations Artificial Intelligence: Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. Array: An array is similar data saved on a computer system in a sequential form. Assembler: A program that translates mnemonic statement into executable instruction. Attribute: The characteristics of an entity are called its attributes. BIOS: BIOS stands for Basic Input/Output System. It gives the computer a platform to run the software using a floppy disk or a hard disk. BIOS is responsible for booting a PC. Bit: Bit is Binary Digit. It refers to a digit number, either a 0 or a 1. The binary digit is used to represent computerized data. Backup: A copy of a file or disk you make for archiving purposes. Backspace: Backspace key is used on the keyboard to delete the text. Backspace will delete the text to the left of cursor. Bandwidth: The maximum amount of data that can travel in a communication path in a given time, measured in bits per second (bps). Bar Code: A bar code is a machine-readable representation of information in a visual format on a surface. The first bar code system was developed by Norman Joseph Woodland and Bernard Silver in 1952. Bitmap: A method of storing a graphic image as a set of bits in a computer memory. To display the image on the screen, the computer converts the bits into pixels. Blog: It is a discussion or informational site published on the world wide web. Bomb: A type of virus designed to activate at a specific date and time on your computer. Bluetooth: A protocol that permits a wireless exchange of information between computers. cell phone and other electronic devices within a radius about 30 feet, Booting: Booting is a bootstrapping process which starts the operating system when a computer is switched on Page 44 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Botnet: It is a collection of internet connected programs communicating with other similar programs in order to perform tasks. Boot Sequence: A boot sequence is the set of operations the computer performs when it is switched on which loads an operating system. Browser: A special software that enables users to read/view web pages and jump from one web page to another. Buffering: The process of storing data in a memory device, allowing the devices to change the data rates,perform error checking and error retransmission. Bug: A software bug is an error, flaw, failure, or fault in a computer program or system that produces an incorrect or unexpected result. Boolean: An expression, the value of which is either true or false. BUS: A bus is a set of wires that enables flow of data from one location of the computer to another. Byte: Eight bits is equal to 1 byte. CGI: CGI stands for Common Gateway Interface. It defines how an auxiliary program and a Web server would communicate. Class: A group of objects having same operations and attributes is defined as a class. Client: A client is a program that asks for information from other processes or programs. Outlook Express is a great example of a client. CD-ROM: An acronym for Compact Disc Read-Only Memory. Client – Server: A common form of distributed system in which software is split between server tasks and client tasks. A client sends requests to a server, according to some protocol, asking for information or action, and the server responds. Clipboard - A portion of memory where the Mac temporarily stores information. Called a Copy Buffer in many PC applications because it is used to hold information which is to be moved, as in word processing where text is "cut" and then "pasted". Clock Rate (MHz) - The instruction processing speed of a computer measured in millions of cycles per second (i.e., 200 MHz). Compiler - a program the converts programming code into a form that can be used by a computer. Compression - a technique that reduces the size of a saved file by elimination or encoding redundancies (i.e., JPEG, MPEG, LZW, etc.) Page 45 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams CPU: The Central Processing Unit. The processing chip that is the "brains" of a computer. Cache Memory: The speed of CPU is extremely high compared to the access time of main memory Therefore, the performance of CPU decreases due to the slow speed of main memory. To decrease the mismatch in operating speed, a small memory chip is attached between CPU and main memory whose access time is very close to the processing speed of CPU It is called the Cache Memory. Chip: A tiny wafer of silicon containing miniature electric circuits that can store millions of bits of information. Client-Server: Client-server is a network architecture which separates the client from the server. Each instance of the client software can send requests to a server or application server. Cookie: A packet of information that travels between a browser and the web server Compiler: A compiler is a computer program that -translates a series of instructions written in one computer language (called the source language) into another computer language (also called the object or target language). Communication: The transrnission of data from one computer to another or from one device to another is called communication. Computer Networks: A computer network is a system or communication among two or more computers. The computer networks can be broadly classified as Homogenous' and 'Heterogeneous'. Computer Graphics: Computer Graphics are visual presentations on a computer screen. Examples are photographs, drawings, line arts, graphs, diagrams, typography numbers, symbols, geometric designs, maps, engineering drawings or other images. Cold Boot: When a computer restarts after the power cut is called cold boot Control Panel: Control Panel is the part of Windows menu. accessible from the start menu, which allows users to view and manipulate basic system settings and controls, such as adding hardware. adding/removing software, controlling user accounts, changing accessibility options, etc. Control Unit: A control unit is the part of a CPU that 'erects its operation. The outputs of this unit control The activity of the rest of the device. Cracker: The preferred term used to refer to a computer criminal who penetrates a computer to steal information or damage the program in some way Crash - a system malfunction in which the computer stops working and has to be restarted. Cursor - The pointer, usually arrow or cross shaped, which is controlled by the mouse. CMOS: CMOS is an abbreviation for Complementary Metal-Oxide-Semiconductor. It is the battery powered chip that is situated on the Motherboard that retains system information such as date and time. Page 46 of 65 Subscribe The Xpress Video Course & Mock Test Package for Bank & Insurance Exams If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: [email protected]  Basics of computers and computer Applications for SSC & Railway Exams Data: Data refers to the information that is saved on a computer. DOS: DOS is an acronym for Disc Operating System. It is a command line operating system launched by Bill Gates. Database - an electronic list of information that can be sorted and/or searched. Defragment - (also - optimize) to concatenate fragments of data into contiguous blocks in memory or on a hard drive. Dialog box - an on-screen message box that appears when the computer requires additional information before completing a command. Digitise - To convert linear, or analogue, data into digital data that can be used by the computer. Disk - a spinning platter made of magnetic or optically etched material on which data can be stored. Disk drive: The machinery that writes the data from a disk and/or writes data to a disk. Disk window: The window that displays the contents or directory of a disk. Document - a file you create, as opposed to the application which created it. DOS - acronym for Disk Operating System - used in IBM PCs. Download - to transfer data from one computer to another. (If you are on the receiving end, you are downloading. If you are on the sending end, you are uploading). Drag - to move the mouse while its button is being depressed. Driver - a file on a computer that tells it how to communicate with an add-on piece of equipment (like a printer). DTP: Desk Top Publisher (ing) is a term that describes a program that enables users to create, design, and print items such as business cards, birthday cards, letterheads, calendars, invitations, and so on. Editing: The process of changing information by inserting, deleting, replacing, rearranging and reformation. E-mail: Electronic mail, abbreviated e-mail is a method of composing, sending, storing and receiving messages over electronic communication systems. Encapsulation: It is a mechanism that associates the code and the data it manipulates into a single unit and keeps them safe from external interference. Encryption: In cryptography, encryption is the process of encoding messages (or information) in such a way that hackers cannot read it, but the authorised users can access it. End User: Any individual who uses the information oefierated by a computer based system. Page 47 of