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History Of Computers

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History of Computers The first counting device was used by the primitive people. They used sticks, stones and bones as counting tools. As human mind and technology improved with time more computing devices were developed. Some of the popular computing devices starting with the first to recent ones are described below; Abacus The history of computer begins with the birth of abacus which is believed to be the first computer. It is said that Chinese invented Abacus around 4,000 years ago. It was a wooden rack which has metal rods with beads mounted on them. The beads were moved by the abacus operator according to some rules to perform arithmetic calculations. Abacus is still used in some countries like China, Russia and Japan. An image of this tool is shown below; Napier's Bones It was a manually-operated calculating device which was invented by John Napier (1550-1617) of Merchiston. In this calculating tool, he used 9 different ivory strips or bones marked ...
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Scan Converting a sStraight Line

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Scan Converting a Straight Line A straight line may be defined by two endpoints & an equation. In fig the two endpoints are described by (x 1 ,y 1 ) and (x 2 ,y 2 ). The equation of the line is used to determine the x, y coordinates of all the points that lie between these two endpoints. Using the equation of a straight line, y = mx + b where m = & b = the y interrupt, we can find values of y by incrementing x from x =x 1 , to x = x 2 . By scan-converting these calculated x, y values, we represent the line as a sequence of pixels. Properties of Good Line Drawing Algorithm: 1. Line should appear Straight: We must appropriate the line by choosing addressable points close to it. If we choose well, the line will appear straight, if not, we shall produce crossed lines. The lines must be generated parallel or at 45° to the x and y-axes. Other lines cause a problem: a line segment through it starts and finishes at addressable points, may happen to pass through no an...
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Computer Virus

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Computer virus A computer virus is a type of malware that, when executed, replicates itself by modifying other computer programs and inserting its own code. [1] When this replication succeeds, the affected areas are then said to be "infected" with a computer virus. [2] [3] Virus writers use social engineering deceptions and exploit detailed knowledge of security vulnerabilities to initially infect systems and to spread the virus. The vast majority of viruses target systems running Microsoft Windows , [4] [5] [6] employing a variety of mechanisms to infect new hosts, [7] and often using complex anti-detection/stealth strategies to evade antivirus software . [8] [9] [10] [11] Motives for creating viruses can include seeking profit (e.g., with ransomware ), desire to send a political message, personal amusement, to demonstrate that a vulnerability exists in software, for sabotage and denial of service , or simply because they wish to explore cybersecurity ...
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