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Information System Hardware

Information System Hardware. Why information systems need hardware Speed: computers provide fast processing of business transactions and information Accuracy: computers ensure accuracy by not making mistakes as people do Capacity: computers provide the ability to handle large amounts of data.

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Information System Hardware

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  1. Information System Hardware www.assignmentpoint.com

  2. Why information systems need hardware • Speed: computers provide fast processing of business transactions and information • Accuracy: computers ensure accuracy by not making mistakes as people do • Capacity: computers provide the ability to handle large amounts of data www.assignmentpoint.com

  3. Input & Output Devices • Input - keyboards, pointing devices, other • Output - screens, printer, other • Terminals (input and output combined) • Multimedia input and output • Virtual reality input and output www.assignmentpoint.com

  4. Input & Output Devices (cont’d) • Keyboards: • Most widely used input device • May be general layout or special purpose • Can cause repetitive strain injuries (RSI) • Carpal tunnel syndrome is an RSI • Keyboards can be specially designed to avoid problems using ergonomics www.assignmentpoint.com

  5. Input & Output Devices (cont’d) • Keyboards (cont’d) www.assignmentpoint.com

  6. Input & Output Devices (cont’d) • Pointing devices • Mouse • Trackball • Trackpoint • Touchpad • Purposes are to move the cursor and select what the computer does next www.assignmentpoint.com

  7. Input & Output Devices (cont’d) • Pointing devices (cont’d) www.assignmentpoint.com

  8. Input & Output Devices (cont’d) • Other input devices - Touch input • Touch screen • Pen input device • Touchpad • Light pen • Digitizer tablet www.assignmentpoint.com

  9. Input & Output Devices (cont’d) • Other input devices - Touch input (cont’d) www.assignmentpoint.com

  10. Input & Output Devices (cont’d) • Other input devices - Optical scanning • Bar code scanner (uses barcodes and UPC codes) • Image or Page Scanner (or scanner) • Optical character recognition or OCR • Mark sense www.assignmentpoint.com

  11. Input & Output Devices (cont’d) • Other input devices • Magnetic scanning • Magnetic strip reader • Magnetic ink character recognition/MICR • Voice input • Voice recognition and IVR systems • Requires training www.assignmentpoint.com

  12. Input & Output Devices (cont’d) • Screens • Characters and images are formed from picture elements or pixels • Resolution is the number of pixels that can be displayed on a screen at one time • Most common screen is a Cathode ray tube or CRT www.assignmentpoint.com

  13. Input & Output Devices (cont’d) • Screens (cont’d) • Monitors may vary in size • CRTs display images well, but are bulky • Flat panel screens are lighter weight and use liquid crystal displays • Ergonomic factors: brightness, contrast, tilt capabilities, glare screens www.assignmentpoint.com

  14. Input & Output Devices (cont’d) • Printers • Desktop or high-volume (stand-alone) • Impact vs. Non-impact • Serial: characters per second (cps) • Line: lines per minute (lpm) • Page: pages per minute (ppm) • Quality: draft, near-letter, and letter www.assignmentpoint.com

  15. Input & Output Devices (cont’d) • Printers (cont’d) • Desktop • Inkjet - nonimpact, sprays ink on paper • Laser - nonimpact, similar to a copier • Dot-matrix - impact, uses a ribbon to form an image with a group of dots www.assignmentpoint.com

  16. Input & Output Devices (cont’d) • Printers (cont’d) • High Volume • Line printers - impact, uses a ribbon, similar to a dot matrix, draft quality • Laser - nonimpact, 200 ppm, letter quality, used for large volume printing www.assignmentpoint.com

  17. Input & Output Devices (cont’d) • Printers (cont’d) • High Volume (cont’d) www.assignmentpoint.com

  18. Input & Output Devices (cont’d) • Other output devices • Plotters - graphics on paper • Voice output - text-to-speech synthesis • Sound output - can be tones, music, beeps, etc. www.assignmentpoint.com

  19. Input & Output Devices (cont’d) • Other output devices (cont’d) www.assignmentpoint.com

  20. Input & Output Devices (cont’d) • Terminals (input and output combined) • Also called a video display terminal/VDT • Dumb terminals can only send and receive data to and from a computer • Intelligent terminals can also do some basic processing • Can be a PC, ATM, cash register www.assignmentpoint.com

  21. Input & Output Devices (cont’d) • Multimedia input and output • Data in more than one form • still or moving pictures • voice, music, other sound • animation • Used in highly interactive presentations • Requires speakers or headphones www.assignmentpoint.com

  22. Input & Output Devices (cont’d) • Multimedia input and output (cont’d) • Input requirements depend on the presentation (e.g. touch screen kiosks) • Usage may require a keyboard and/or a pointing device • Creations requires audio/video equipment • Images and sounds are digitized www.assignmentpoint.com

  23. Input & Output Devices (cont’d) • Virtual reality input and output • Creates a non-real, virtual world through sight and sound • Uses a headset for sight, and headphones for sound • May use a glove for touch and a joystick to control and move in the virtual world www.assignmentpoint.com

  24. Input & Output Devices (cont’d) • Virtual reality input and output (cont’d) • Uses • Entertainment • Train doctors • Architecture • Criminal investigations, simulations, and courtroom re-enactments www.assignmentpoint.com

  25. Primary Storage • Primary storage structure • Data representation • Primary storage organization • Primary storage capacity www.assignmentpoint.com

  26. Primary Storage (cont’d) • Primary storage structure • Composed of silicon chips • Each chip has millions of electronic circuits that can be off or on (0 or 1) • Called volatile storage • Random access memory (RAM) • Read only memory (ROM) www.assignmentpoint.com

  27. Primary Storage (cont’d) • Primary storage structure (cont’d) www.assignmentpoint.com

  28. Primary Storage (cont’d) • Data representation • Binary representation: binary digits/bits • 2 main formats: • ASCII: American Standard Code for Information Interchange • EBCDIC: Extended Binary Coded Decimal Interchange Code www.assignmentpoint.com

  29. Primary Storage (cont’d) • ASCII • A character consists of 7 bits • 128 characters/combinations of 7 bits • Computers use 8 bits for 256 characters J O H N 1001010 1001111 1001000 1001110 www.assignmentpoint.com

  30. Primary Storage (cont’d) • EBCDIC • A character consists of 8 bits • 256 characters/combinations of 8 bits J O H N 11010001 11010110 11001000 11010101 www.assignmentpoint.com

  31. Primary Storage (cont’d) • Data representation problems • ASCII and EBCDIC computers cannot communicate without special HW/SW • 256 characters may not be enough in the future • Potential successor is 16 bit Unicode www.assignmentpoint.com

  32. Primary Storage (cont’d) • Primary storage organization • Bits are arranged into storage locations • Computers use 8 bits and store one character in each location, sometimes adding a parity bit • Byte: group of bits to store one character • Each location has a unique address www.assignmentpoint.com

  33. Primary Storage (cont’d) • Primary storage organization (cont’d) www.assignmentpoint.com

  34. Primary Storage (cont’d) • Primary storage capacity • Kilobyte = 1024 bytes (about 1 thousand) • Megabyte = 1,048,576 (about 1 million) • Gigabyte = about 1 billion • Terabyte = about 1 trillion www.assignmentpoint.com

  35. Central Processing Unit (CPU) • Structure • Compatibility • Speed • Common CPUs www.assignmentpoint.com

  36. CPU (cont’d) • Structure • Composed of one or more chips containing millions of electronic circuits • Composed of • Arithmetic Logic Unit (ALU)-performs calculations and compares values • Control Unit - analyzes and executes instructions in programs www.assignmentpoint.com

  37. CPU (cont’d) • Structure (cont’d) www.assignmentpoint.com

  38. CPU (cont’d) • Compatibility • Instructions in machine language (0 or 1) • Different CPUs use different machine languages • Various CPUs may not be compatible • CPUs are compatible if their machine languages are identical www.assignmentpoint.com

  39. CPU (cont’d) • Speed • Factors: • bits/second processing capability • amount of data transferred between CPU and primary storage • Data transfer speed is measured in fractions of a second (milli, micro, nano) www.assignmentpoint.com

  40. CPU (cont’d) • Speed (cont’d) • Clock speed is measured in megahertz, one million cycles (ticks) per second • Reduced Instruction Set Computing (RISC) systems - smaller instruction set • Faster • Less expensive www.assignmentpoint.com

  41. CPU (cont’d) • Common CPUs • Microcomputer • Uses a single chip - a microprocessor • First developed by Intel - 4004 • Now at Pentium II/Pro with MMX (multimedia enhanced capabilities) • Apple used a Motorola 68000 www.assignmentpoint.com

  42. CPU (cont’d) • Common CPUs (cont’d) • Microcomputer (cont’d) • Intel and Motorola chips are not compatible-different machine language • Computer manufacturers use chips from other companies (e.g Intel) • Many may use the same chip www.assignmentpoint.com

  43. CPU (cont’d) • Common CPUs (cont’d) • Mini- and mainframe computers • May use computer chips manufactured by the computer company • These computers are not usually compatible because of different chips • A DEC program can’t run on an IBM www.assignmentpoint.com

  44. CPU (cont’d) • Common CPUs (cont’d) • Supercomputers • Similar to mini- and mainframes • May use 64 or 128 bit chips • Multiprocessing - using several CPUs in the same computer at the same time • Massively parallel - many processors www.assignmentpoint.com

  45. Secondary Storage • Magnetic Disk • Optical Disk • Magnetic Tape www.assignmentpoint.com

  46. Secondary Storage (cont’d) • Magnetic Disk • Most widely used secondary storage type • Flat, round platter • Made of metal or plastic • Covered with metallic coating which can be magnetized at different spots • Each magnetized spot is a 0 or a 1 www.assignmentpoint.com

  47. Secondary Storage (cont’d) • Magnetic Disk (cont’d) • Bits are organized into concentric circles known as tracks • Bits are grouped in tracks to form bytes • Each byte represents one character • Capacity depends on the number of bytes per track and the total number of tracks www.assignmentpoint.com

  48. Secondary Storage (cont’d) • Magnetic Disk (cont’d) www.assignmentpoint.com

  49. Secondary Storage (cont’d) • Magnetic Disk (cont’d) • May store trillions of bytes • Disk is non-volatile storage • Several platters may form a disk pack • Sizes range from 2 inches to 14 inches • Common floppy size is 3 1/2 • Only form of storage for some computers www.assignmentpoint.com

  50. Secondary Storage (cont’d) • Magnetic Disk Drives • Stores data on magnetic disks • Retrieves data from magnetic disks • Rotates the disk at speeds from 300 to 7000 rpms depending on type www.assignmentpoint.com

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