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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

  28. Monitor or screen Text Numbers Symbols Art Photographs Video Printer Black and white Color Output devices • Convert from electronic form to some other form • May display the processed results • Usable information

  29. Output Devices Output devices make the information resulting from the processing available for use. The two output devices are as follows: Printer Monitor Printer The printer produces a hard copy of your output, and the computer screen produces a soft copy of your output.

  30. Output Devices Monitor • There are two basic types of monitors: • CRT (cathode ray tube) monitors • LCD (liquid crystal display) monitors. • Both types produce sharp images, but LCD monitors have the advantage of being much thinner and lighter. CRT monitors, however, are generally more affordable

  31. The Processor Central Processing Unit (CPU) • Converts data to useful information • Interpret and execute instructions • Communicate with input, output and storage

  32. Motherboard • The motherboard is the computer's main circuit board. • It's a thin plate that holds the CPU, memory, connectors for the hard disk drive and optical drives, expansion cards to control the video and audio, as well as various external ports and peripherals. • The motherboard connects directly or indirectly to every part of the computer.

  33. Computer Memory • Computer Memory are internal storage areas in the computer . • used to either temporarily or permanently store data or instructions to be processed.

  34. Computer Memory

  35. Volatile Memory Loses its contents when the computer's power is turned off volatile memory Loses its contents when the computer's power is turned off nonvolatile memory Does not lose its contents when the computer’s power is turned off Memory What are the two types of memory in the system unit?

  36. Also called primary storage and main memory, chips that temporarily holds software instructions and data before and after it is processed by the CPU. RAM is the working memory of the computer. What is random access memory (RAM)?

  37. BIOS (basic input/output system) Stored on ROM Sequence of instructions the computer follows to load the operating system and other files when you first turn on the computer Nonvolatile — Contents not lost when the computer is turned off Data can only be read, cannot be modified What is read-only memory (ROM)? • Memory chips that contain data, instructions, or information that is recorded permanently

  38. Memory also called Random Access Memory or RAM (temporary memory) is the main memory of the computer. It consists of electronic components that store data including numbers, letters of the alphabet, graphics and sound. Any information stored in RAM is lost when the computer is turned off. Read Only Memory or ROM is memory that is engraved on a chip that has start-up directions for your computer. It is permanent memory. Memory

  39. Two Types of Storage • Secondary storage long-term storage • Primary storage or memory temporary storage

  40. Storage Devices Primary Storage Devices • Also known as internal memory and main memory. • The fastest type of memory in your computer and is used to store data while it's being used. • Computer RAM and cache are both examples of a primary storage device. • For example, when you open a program data is moved from the secondary storage into the primary storage. • Unless this information is saved to a Secondary Storage Device, it will be lost when the computer is powered down.

  41. Storage Devices RAM (Random Access Memory) • Computer’s short-term memory. • Data is temporarily stored here until you save your work to the hard disk. • RAM is used by the system to store data that is processed by a computer's CPU. • RAM is a volatile memory and requires power; if power is lost, all data is also lost.

  42. Secondary Storage Devices Secondary Storage Devices Also known as external memory and auxiliary storage, secondary storage • Used to store data when they are not being used in memory. • The most common types of auxiliary storage used on personal computers are: • floppy disks, hard disks, CD-ROM drives, USB

  43. Secondary Storage Devices Floppy Disks A portable, inexpensive storage medium that consists of a thin, circular, flexible plastic disk with a magnetic coating enclosed in a square-shaped plastic shell. Initially Floppy disks were 8-inches wide, they then shrank to 5.25 inches, and today the most widely used floppy disks are 3.5 inches wide and can typically store 1.44 megabytes of data.

  44. Structure Of Floppy Disks Initially Floppy disks were 8-inches wide, they then shrank to 5.25 inches, and today the most widely used folly disks are 3.5 inches wide and can typically store 1.44 megabytes of data. A folly disk is a magnetic disk, which means that it used magnetic patterns to store data. Data in floppy disks can be read from and written to. Formatting is the process of preparing a disk for reading and writing. A track is a narrow recording band that forms a full circle on the surface of the disk.

  45. The disk’s storage locations are divided into pie-shaped sections called sectors. • A sectors is capable of holding 512 bytes of data. • A typical floppy stores data on both sides and has 80 tracks on each side with 18 sectors per track. Structure Of Floppy Disks

  46. Secondary Storage Devices Hard Disks • Consists of one or more rigid metal plates coated with a metal oxide material that allows data to be magnetically recorded on the surface of the platters. • The hard disk platters spin at a high rate of speed, typically 5400 to 7200 revolutions per minute (RPM). • Storage capacities of hard disks for personal computers range from 10 GB to 120 GB.

  47. Secondary Storage Devices Compact Discs (CD) • Also called an optical disc, is a flat round, portable storage medium that is usually 4.75 inch in diameter. • Standard CD can hold 700MB of data, around 80minutes of CD quality audio, or up to 60minutes of video. • The later standard called the DVD (Digital Versatile Disc) is still an optical media much like the CD but with much greater capacities, starting at 4.7GB at the low end to as high as 17GB.

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