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1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
1.introduction to computers
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1.introduction to computers

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for combuter learning beginers

for combuter learning beginers

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  • 1. Introduction to Computers 1
  • 2. What Is A Computer?A computer is an electronic device, operatingunder the control of instructions (software)stored in its own memory unit, that can acceptdata (input), manipulate data (process), andproduce information (output) from theprocessing. Generally, the term is used todescribe a collection of devices that functiontogether as a system. 2
  • 3. Charles Babbage - 1792-1871 Difference Engine c.1822 Analytical Engine  huge calculator, never finished Analytical Engine 1833  could store numbers  calculating “mill” used punched metal cards for instructions  powered by steam!  accurate to six decimal places
  • 4. Devices that comprise a computer system Monitor Speaker (output) (output) System unit (processor, memory…)Printer(output) Storage devices (CD-RW, Floppy, Hard disk, zip,…) Mouse (input) Scanner Keyboard (input) (input) 4
  • 5. What Does A Computer Do?Computers can perform four generaloperations, which comprise the informationprocessing cycle. Input Process Output Storage 5
  • 6. Data and Information All computer processing requires data, which is a collection of raw facts, figures and symbols, such as numbers, words, images, video and sound, given to the computer during the input phase. Computers manipulate data to create information. Information is data that is organized, meaningful, and useful. During the output Phase, the information that has been created is put into some form, such as a printed report. The information can also be put in computer storage for future use. 6
  • 7. Why Is A Computer So Powerful? The ability to perform the information processing cycle with amazing speed. Reliability (low failure rate). Accuracy. Ability to store huge amounts of data and information. Ability to communicate with other computers. 7
  • 8. How Does a Computer Know what to do? It must be given a detailed list of instructions, called a compute program or software, that tells it exactly what to do. Before processing a specific job, the computer program corresponding to that job must be stored in memory. Once the program is stored in memory the computer can start the operation by executing the program instructions one after the other. 8
  • 9. What Are The Primary Components Of A Computer ? Input devices. Central Processing Unit (containing the control unit and the arithmetic/logic unit). Memory. Output devices. Storage devices. 9
  • 10. Input Devices Keyboard. Mouse. 10
  • 11. The KeyboardThe most commonly used input device is thekeyboard on which data is entered bymanually keying in or typing certain keys. Akeyboard typically has 101 or 105 keys. 11
  • 12. The MouseIs a pointing device which is used to controlthe movement of a mouse pointer on thescreen to make selections from the screen. Amouse has one to five buttons. The bottom ofthe mouse is flat and contains a mechanismthat detects movement of the mouse. 12
  • 13. The Central processing UnitThe central processing unit (CPU) containselectronic circuits that cause processing tooccur. The CPU interprets instructions to thecomputer, performs the logical and arithmeticprocessing operations, and causes the inputand output operations to occur. It isconsidered the “brain” of the computer. 13
  • 14. MemoryMemory also called Random Access Memoryor RAM (temporary memory) is the mainmemory of the computer. It consists ofelectronic components that store dataincluding numbers, letters of the alphabet,graphics and sound. Any information stored inRAM is lost when the computer is turned off.Read Only Memory or ROM is memory thatis etched on a chip that has start-updirections for your computer. It is permanentmemory. 14
  • 15. Amount Of RAM In Computers The amount of memory in computers is typically measured in kilobytes or megabytes. One kilobyte (K or KB) equals approximately 1,000 memory locations and one megabyte (M or MB) equals approximately one million locations A memory location, or byte, usually stores one character. Therefore, a computer with 8 MB of memory can store approximately 8 million characters. One megabyte can hold approximately 500 pages of text information. 15
  • 16. Output DevicesOutput devices make the information resultingfrom the processing available for use. Thetwo output devices more commonly used arethe printer and the computer screen.The printer produces a hard copy of youroutput, and the computer screen produces asoft copy of your output. 16
  • 17. Storage DevicesAuxiliary storage devices are used to storedata when they are not being used inmemory. The most common types of auxiliarystorage used on personal computers arefloppy disks, hard disks and CD-ROM drives. 17
  • 18. Computer SoftwareComputer software is the key toproductive use of computers.Software can be categorized intotwo types: Operating system software Application software. 18
  • 19. Operating System SoftwareOperating system software tells the computerhow to perform the functions of loading,storing and executing an application and howto transfer data.Today, many computers use an operatingsystem that has a graphical user interface(GUI) that provides visual clues such as iconsymbols to help the user. Microsoft Windows7 is a widely used graphical operatingsystem. DOS (Disk Operating System) is anolder but still used operating system that istext-based. 19
  • 20. Application Software Application Software consists of programs that tell a computer how to produce information. Some of the more commonly used packages are:  Word processing  Electronic spreadsheet  Database  Presentation graphics 20

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