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Explain different types of storage devices

Topic: Explain different types of storage devices in Computer systems Storage Devices Storage devices are used to store data and instructions permanently. Storage devices are also called secondary storage devices / backing storage devices / external storage devices or auxiliary storage devices. Examples of storage devices include Hard Disk, CD and DVD etc. Why Secondary Storage Devices are Used? Secondary storage devices are used because: Primary memory(RAM) is volatile and temporary. When computer is switched off, all data in ram is erased. Storage devices can store large amounts of data and instructions permanently whereas Primary memory has less capacity of storing data. Types Of Storage Devices There are three main types of storage devices:  Magnetic Tape   Magnetic Disk   Optical Disk   Flash Memory storage devices 1. Magnetic Tape Magnetic tape is the oldest storage device. It is made of plastic coated with m...
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Explain Different Types Of Output Devices

Output devices Out put devices are used to display results of processing to the user. They perform the following functions:  Receive results from memory  Convert data into human readable form  Display results to the user Examples include: Monitor, printer, plotter, speaker, and multimedia projector. Different Types of Output Devices 1.    Monitor LCD Monitor CTR Monitor     Monitor is the most commonly used output device used to display results of processing. It has a TV like shape. Pictures on monitor are formed with picture elements called PIXEL. Monitors may be Monochrome that will display results in Black & White. Color Monitors are also available. They display results in multi colors. Monitor produces soft copy output. 2.    Printers Printers are used to produce hard copy out put. They print processing results on paper. Printers are divided into two main categories: · ...
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Using Simple Formulas in Excel With Arithmetic Operators-2

What are Arithmetic Operators in Excel? Arithmetic Operators are used to perform arithmetic operations like addition, subtraction, multiplication and division etc. There are following arithmetic operators in Microsoft Excel: Using Arithmetic / Mathematical Operators in MS Excel Formulas 1.  + Operator The + arithmetic operator is used to perform addition of numbers. It is used with in formulas along with Cell References normally. For example, to add the number 10 in A1 cell and the number 20 in B1 cell, we can write a formula =A1+B1 in cell C1. After pressing Enter key we will see the answer 30 in the cell C1. Important Points To Write a Simple Formula in Excel Every formula in Microsoft Excel is started with an Equal sign ( = ). Arithmetic operators (+ for addition, - for subtraction, * for multiplication, / for division) are used. Percentage is calculated by % operator. ( =B2*10%       means 10% of the number in cell B2) Pow...
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