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Lecture # 2

Lecture # 2. Computer Hardware. Computers are all around!. Grocery store Schools Libraries Bank Mail Malls. We interact with computers everyday!. Computer System.

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Lecture # 2

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  1. Lecture # 2 ComputerHardware

  2. Computers are all around! • Grocery store • Schools • Libraries • Bank • Mail • Malls We interact with computers everyday!

  3. Computer System A computer is an electronic device, operating under the control of instructions (software) stored in its own memory unit, that can accept data (input), manipulate data (process), and produce information (output) from the processing. Generally, the term is used to describe a collection of devices that function together as a system.

  4. Computer System A computer is an electronic device used to process data. • A computer can convert data into information that is useful to people. • A complete computer system includes four distinct parts: • Hardware • Software • Data • User

  5. Understanding Computer “A computer is a programmable machine that receives input, storesandmanipulatesdata/information, and provides output in a useful format.”

  6. Hardware All the machinery and equipment in a computer system Software All the instructions that tell the computer how to perform a task Computers consist of hardware and software. If you can touch it, it’s hardware

  7. Off and On • Computers only recognize off and on, like a light switch • These switches are represented as binary digits or… bits • Instructions and data are composed only of a series of bits

  8. 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

  9. How Does a Computer Know what to do? • It must be given a detailed list of instructions, called a compute program, algorithms 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.

  10. 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.

  11. How a Computer System Works Storage Information Data Input Output Process

  12. Function of Computer System Data handling I Input P Process O Output S Storage

  13. 01101111 10001111 01101010 10000000 01001010

  14. Off and On • Computers only recognize off and on, like a light switch • These switches are represented as binary digits or… bits • Instructions and data are composed only of a series of bits

  15. HARDWARE: Your Physical Interface • A binary digit (bit) is the smallest unit of information that your computer can process. • A bit can be either 1 (on) or 0 (off). • ASCIIis a common coding system used to represent all characters, symbols and numbers in binary form. • In ASCII a group of 8 bits is called a byte.

  16. HARDWARE: Your Physical Interface Example: • If you type cool on the keyboard, your keyboard would change it into four bytes as follows: 01000011 01001111 01001111 01001100 C o o l

  17. Bytes • Eight bits form a single byte • “00110011” is One Byte of Information • Byte Values: • 00000000 = 0 • 11111111 = 255 • As a result, binary numbers almost always written as a full byte (00000001).

  18. We count in Base 10 (Decimal) 19 18 17 16 15 3 4 5 24 6 10 9 2 11 12 13 8 1 95 14 7 96 97 98 99 100 101 20 21 22 23 0 Ran out of symbols (0-9), so increment the digit on the left by one unit.

  19. Computers count in Base 2 (Binary) • Counting in Binary is the same, but with only two symbols • On (1) • Off (0) 10000 1001 1010 1011 1000 1101 1110 1111 1100 0 111 101 100 11 10 1 110

  20. Converting Binary to Decimal 1 0 1 0 1 1 0 0 128 64 32 16 8 4 2 1 128 + 0 + 32 + 0 + 8 + 4 + 0 + 0 128 + 32 + 8 + 4 = 172

  21. Converting Binary to Decimal 0 1 0 1 0 0 0 1 128 64 32 16 8 4 2 1 0 + 64 + 0 + 16 + 0 + 0 + 0 + 1 64 + 16 + 1 = 81

  22. Converting Binary to Decimal - - -  -  128 64 32 16 8 4 2 1 0 + 0 + 0 + 16 + 0 + 4 + 2 + 1 16 + 4 + 2 + 1 = 23

  23. Size Matters Computer memory and storage capacities are represented by their size (megs, gigs, etc) • 1 , 0   = 1 bit • 4 bits = 1 hex character (nibble) • 8 bits = 1 byte • 2^10 = 1,024 bytes or 1 Kilobyte (thousand) • 2^20 = 1,048,576 bytes or 1 Megabyte (million) • 2^30 = 1,073,741,824 or 1 Gigabyte (billion) • 2^40 = 1,099,511,627,776 bytes or 1 Terabyte (trillion)

  24. Generic Input devices • Accept data or commands and convert them to electronic form • Getting data into the computer • Typing on a keyboard • Pointing with a mouse • Scanning with a wand reader or bar-code reader

  25. Generic Input Devices Keyboard • Data is entered by manually typing certain keys. • A keyboard typically has 101 or 105 keys. • Most keyboards use the QWERTY layout, named for the first six keys in the top row of letters. gaming keyboard Rollup Keyboards

  26. Generic Input Devices MOUSE • Is a pointing device which is used to control the movement of a mouse pointer on the screen to make selections from the screen. • The bottom of the mouse contains a mechanism that detects movement of the mouse.

  27. Specialized Input Devices

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