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Computers Simplified

Computers Simplified

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Computers Simplified

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  1. Computers Simplified Supplemental Lecture Notes

  2. Introduction Chapter 1

  3. Parts of A Computer • Hardware – you can see it or touch it • Software – set of electronic instructions • Application software – specific tasks • Operation software – controls overall activity • Peripherals – anything attached

  4. What Computers Do • A computer collects (input), processes, stores and outputs information.

  5. Storage Simplified • Bit: on or off • Smallest unit of information in a computer • Byte: one character • 8 binary digits

  6. Bigger Is Better • Kilobyte (KB) • 1,024 character • One double-spaced typed page • Megabyte (MB) • 1,048,576 characters • A book • Gigabyte (GB) • 1,073,741,824 • A shelf of books • Terabyte (TB) • 1,099,511,511,627,776 characters • A library of books

  7. Set-top Box • Computer device that you connect to your television. • Use telephone or cable connection • Email of Internet

  8. Typical System • Computer case • Monitor • Printer • Speakers • Modem • Keyboard • Mouse

  9. Computer Components • Power supply • Hard drive • Expansion card • Expansion slot • System board • CD-ROM or DVD-ROM • Floppy disk • Drive bay • Central Processing Unit (CPU) • Random access memory (RAM)

  10. Power Plays • The capacity of a power supply is measured in watts • Computer uses 250; light bulb uses 60 • Can use • Surge protector • UPS

  11. Ports • Ports are connectors at the back of a computer system that you use to plug in an external device. This allow instructions and data to flow between the computer and the device

  12. Any Port in a Storm • Parallel port – 25 holes; female connector; LPT1; printer or storage devices • Monitor port • Keyboard port • Serial port – 9 or 25 pins; male connector; COM1; mouse or modem • Game port • Network port • USB port • 127 devices • Printer, modem, joy stick

  13. Growing • An expansion card is a circuit board that lets you add new features to a computer • Video • Modem • Sound • Network Interface

  14. Upgrades • Upgrading refers to replacing an old or obsolete component with a newer component to improve the efficiency of the computer • Upgrading also can include adding a new component like a tape drive or DVD to increase the capabilities of a computer • Increasing the amount of memory in a computer is one of the most effective upgrades you can perform

  15. Input and Output Chapter 2

  16. Mouse Actions • Click – selects • Right click – displays commands • Double click – opens • Drop and Drag – moves items on screen

  17. Mice • Types • Conventional • Wheel mouse • Wireless mouse • Programmable mouse – e.g. three buttons • Optical sensor mouse • Other devices • Touchpad • Trackball • Pointing stick

  18. Keyboards • There are 101 keys on a keyboard to help you input information • Function keys let you perform specific task • Can use CNTL-x shortcuts to execute commands • CNTL-C – copy • CNTL-X – cut • CNTL-V – paste • Windows key will quickly display the start menu

  19. Printers • Speed of a printer is measured in pages per minute (PPM). A higher speed represents faster output • Resolution determines the quality of images • A higher resolution results in sharper images • Printer resolution is measured in dots per inch (dpi) • 600 dpi is acceptable; 1200 is better for images • Resolution expressed with two numbers represents dots per inch across and down

  20. Types of Printers • Ink-jet: has a print head that sprays ink through tiny nozzles onto a page • 2 to 10 pages (ppm) • 360 to 2400 dots per inch • Color printers spray cyan, magenta, yellow and black to create different colors • Laser-printer • Works like a photo copier • Speed of 4 to 16 pages • Have a CPU • 600 to 2400 • Memory – 2mb to 8 Mb

  21. Other Types • Dot matrix • Print head contains small blunt pins that strike an inked ribbon • Useful for multi-part forms • LED printer • Similar to lasers but cheaper • Color photo printer • Multifunction Printer

  22. Print Buffer and Spoolers • Printer buffer: section of memory printer stores information waiting to print • Printer spooler: program on your computer that stores information waiting to print • Stores more information than the buffer • One spooler for each connected printer

  23. Monitors • Video cards translate instructions from the computer into a form Most computes the monitor can understand • require at least 2 mb of video card memory • Accelerated Graphics Port (AGP) – uses AGP bus to communicate directly with main memory • 3D Graphics Accelerator has chip called a GPU optimized for 3-D graphics

  24. Monitor Metrics • The smaller the dot pitch, the crisper the image • 0.28mm is acceptable • Refresh rate is measured in hertz (Hz) • Times per second computer redraws the image • 72 Hz or more is acceptable

  25. Resolution • Amount of information a monitor can display • Measured by the number of horizontal and vertical pixels • Monitors switch settings based on the resolution and refresh rate of video card • Video card determines number of colors a monitor can display • 256 suitable for most home use • 24-bit displays more colors than eye can distinguish

  26. Communications • Modems let a computer exchange information through telephone lines • Speed of a modem determines how fast it sends and receives messages • 56,000 bps (56 Kbps) • V.90 standard: receive 56K and send 33.6K • Speed at which information flows depend on the quality of the phone line • A modem needs a communications package to manage the transmission of information • Data compression – squeezes together data

  27. High-speed Connections • ISDN – Integrated Services Digital Network • Digital phone line • 56 Kbps to 128 Kbps • Cable Modem • Same cable as TV • 4000 Kbps • DSL – Digital subscriber line • High speed digital phone line • 1000 – 6000 Kbps • Satellite

  28. Sound Cards • Sampling Rate: at least 44.1 KHz • Full-duplex • Talk and listen at same time • Musical Instrument Digital Interface (MIDI) support • Wavetable synthesis • Actual recordings • FM synthesis • Imitated sounds

  29. TV Tuner Cards • Require a video card to operate

  30. Scanners • A scanner is a device that reads images and text into a computer • Most scanners come with Optical Character Recognition (OCR) software. This software places scanned text into a document that can be edited in a word processor • Color dept is measured in bits and indicates the number of colors a scanner can detect • 36 bit color depth is acceptable

  31. Resolution • Resolution determines the amount of detail a scanner can detect • Ranges from 600 dpi to 2400 dpi • You usually don’t need to scan at a higher resolution than a printer can produce or a monitor can display • Most monitors are 73 dpi • Printers vary

  32. Cameras • Resolution is measured in megapixels • 1000 x 1000 pixels • 1, 2 and 3 megapixel cameras are available • Digital video cameras use a Charged Coupling Device (CCD) to capture video • Quality depend on amount of detail a CCD can detect • Most CCD’s have resolution between 250,000 and 700,000 pixels • Web cameras – resolution and speed determine quality of image • Common transfer rates • 15 frames per second at 640 x 480 pixels • 30 frames per second at 352 x 288 (clearer but smaller)

  33. MP3 • Sound format used to CD-quality music over the Internet • Compresses sound • Commonly 64 bit memory

  34. USB and Firewire • High-speed ports that allow information to quickly transfer between a computer and an external device • USB • Supports up to 127 device • USB 1.0: 12 megabits per second • USB 2.0: 480 Mbps • FIREWIRE • 63 devices at 400 Mbps • Can purchase Firewire expansion card

  35. Processing Chapter 3

  36. CPU • Central Processing Unit • Processes instructions, performs calculations, and manages the flow of information through a computer system • Performance: • Each generation of CPU is more powerful than the one before • CPU speed is a major factor in determining how fast a computer operates (faster the speed, faster computer operates) • Measured in megahertz (MHz)

  37. Processing • The Central Processing Unit (CPU) is the main chip in a computer • Processes instructions • Performs calculations • Manages the flow of information

  38. Types of CPUs • Intel Pentium Processor • Speeds of 450 MHz to 1.13 GHz • Intel Celeron • Needs of home machines (500-700MHz) • AMD Athlon Processor • Business and home use • AMD Duron Processor • Home use • VIA Cyrix Processor • Inexpensive CPU

  39. Processing • Random Access Memory – Temporarily stores data inside a computer • Constantly overwritten • Measured in megabytes (MB) • 64 minimum these days100 MHz (millions of cycles per second) • Dynamic RAM is type of memory chip that makes up memory in many computer systems. Access speed measured in megabits • Most system boards can support access speed of Single Inline Memory Module (SIMM) – 9 memory chips • Dual Inline Module (DIMM) – 18 memory chips • If you have limited memory or you have many programs open, your computer may need to use part of the hard drive to simulate more memory

  40. Using Memory Cache • Look through documents on your desk (internal cache) • Look through documents in your desk drawer (external cache) • Looking through documents in your filing cabinet (RAM)

  41. Using Memory Cache • Look through documents on your desk (internal cache) • Look through documents in your desk drawer (external cache) • Looking through documents in your filing cabinet (RAM)

  42. Storage Devices Chapter 4

  43. Memory Cache • Speeds up computer by storing data the computer has recently used • Internal Cache: On CPU chip (L1 or primary cache • External Cache: On the system board and consists of Static RAM (SRAM chips) • Sometimes built into chip • RAM – slower main memory • Each time the computer requests data from RAM, the computer places a copy of the data in memory cache • Constantly contains the most recently used data

  44. BUS • Electronic pathway that carries information between devices in a computer • Bus Width (think lanes of a highway) • 8 bits is one character • Bus Speed (think speed limit) • Measured in MHz (millions of cycles per second)

  45. Bus Types • ISA (Industry Standard Architecture) • Slowest and oldest • 16 bits; 8MHz (millions of cycles per second) • Pentium, Pentium II • PCI (Peripheral Component Interconnect) • 32 or 64 bits • 66 MHz • Support Plug and Play • Pentium II, III, 4 • AGP (Accelerated Graphics Port) • Between video card and main memory • 32 bits; 66 MHz

  46. Using a Hard Drive Correctly • Virus protection • Backups • Defragmentation • Prevents files from being broken up for storage • Repairing a Disk • Disk Cleanup • Data compression • Only if disk is running out of space

  47. Hard Drives • Magnetically stores data on rotating disks called platters • Stores your operating system and programs • Document will not be lost when you turn off the computer • Capacity is measured in bytes • Speed is measured in revolutions per minute

  48. File Systems • File system determines how information is stored on a hard drive • FAT • FAT32 • NTFS

  49. Connection Types • EIDE (Enhanced Integrated Drive Electronics) – Called IDE • Supports total of 4 devices (any drives) • Ultra Direct Memory Access (UDMA) is enhanced IDE • SCSI (Small Computer System Interface) • Called ‘scuzzy” • Supports 7 devices • Expensive

  50. Relation of Cache & Hard Drives • Disk cache speeds up the computer by storing the data the computer has most recently used • Constantly updated • Area of memory • Fast access • Then hard drive is searched