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Hardware: Input, Processing, and Output Devices

Hardware: Input, Processing, and Output Devices. Chapter 3. Chapter Topics. Computer system components The power, speed, and capacity of processing and main memory devices. Access methods, capacity and portability of secondary storage devices. Input & output devices

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Hardware: Input, Processing, and Output Devices

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  1. Hardware: Input, Processing, and Output Devices Chapter 3

  2. Chapter Topics • Computer system components • The power, speed, and capacity of processing and main memory devices. • Access methods, capacity and portability of secondary storage devices. • Input & output devices • The popular classes of computer systems

  3. Printer (output) Monitor (output) Speakers (output) System unit (processing and secondary storage) Mouse (input) Keyboard (input) Hardware: Typical System

  4. “Motherboard” “Ports” System Unit “Expansion Slots” CPU Memory Output Devices Input Devices Storage Devices Peripherals Computer Hardware

  5. A “motherboard” On the Motherboard CPU A RAM chip A “firewire” card Pins to attach to The motherboard Expansion slots

  6. Control Unit Fetch Decode Memory Registers Write-back Execute ALU CPU

  7. CPU

  8. Machine Cycle Instruction Cycle Fetch Decode Write-back Execute Execution Cycle

  9. Machine Cycle Time Measures • Microseconds (1 millionth) • Nanoseconds (1 billionth) • Picoseconds (1 trillionth) • MIPS (Millions of Instructions Processed per Second)

  10. If one nanosecond is.. One mile One person One minute One square mile Then one second is equivalent to … 2000 trips to the moon and back Population of China and the U.S. 1900 years 17 times the land are of the world How fast is a Nanosecond?

  11. Fetch Decode “Word sizes” 8 bits 16 bits 32 bits 64 bits Write-back Execute Data Bus

  12. Processing Characteristics • Clock speed: electronic pulses affecting machine cycle time • Hertz: one cycle (pulse) per second • Megahertz (MHz): millions of cycles per second • Microcode: internal, predefined elementary operations in a CPU

  13. Microcode Instruction Sets • Complex instruction set computing: CPU contains many microcode instructions • Reduced instruction set computing (RISC): Minimal set of microcode instructions • Very Long Instruction Word (VLIW): Each microcode instruction is longer and does more.

  14. Multiprocessing • More than one CPU is present • Tasks are divided among CPUs in true “parallel processing” • Parallel processing uses multiple processors to execute instructions in concert.

  15. Parallel Processing Control CPU Combined Results

  16. Physical Characteristics of the CPU • Digital circuits on chips • Electrical current flows through silicon • Moore’s Law states that transistor density of chips will double every 18 months

  17. Memory Characteristics and Functions

  18. ROM CPU Secondary Cache Primary Cache System Bus I/O Bus External Storage Devices Expansion slots Memories Random Access Memory (RAM)

  19. ROM Chip and BIOS • ROM stands for Read Only Memory • ROM is a non-volatile memory on a chip • The ROM chip contains • Basic input/output system BIOS • The BIOS has the instructions necessary • to start up your computer

  20. RAM • RAM stands for Random Access Memory • RAM is a volatile memory on a chip • RAM chips store information in “addresses” • that can be accessed directly and quickly

  21. Storage Media • Storage devices retain data when power is switched off • Storage devices are slower than memory devices like RAM

  22. Memory A temporary holding place for data and instructions Consists of one or more chips on the motherboard Sometimes called primary storage Storage The media on which data, instructions, and information are kept, as well as the devices that record and retrieve these items Storage also called secondary storage, auxiliary storage, permanent storage, or mass storage Storage is nonvolatile Memory Versus Storage

  23. Managing Memory Remember the “Machine Cycle?” Page is “swapped in” Decoding and Execution Page is “swapped out”

  24. Starting Up • BIOS read • from ROM 2. OS “kernel,” or supervisor program becomes memory resident. 3. CPU reads and executes instructions

  25. Storage Capacity The number of bytes (characters) a storage medium can hold Manufacturers use many terms to define the capacity of storage media Storage Term Number of bytes Abbreviation Kilobyte KB 1 thousand Megabyte MB 1 million 1 billion Gigabyte GB Terabyte 1 trillion TB Petabyte PB 1 quadrillion

  26. Data Representation • A computer circuit represents the 0 or the 1 electronically by the presence or absence of an electronic charge. • Binary Digit (Bit): Electronic State 1 On 0 Off • Binary system: two unique digits, 0 and 1 • Bit: the smallest unit of data the computer can represent • A byte: a group of 8 bits: represents a single character in the computer

  27. Bits and Bytes • Byte • Eight bits • Kilobyte - 1 thousand bytes • Megabyte - 1 million bytes • Gigabyte - 1 billion bytes • Terabyte - 1 trillion bytes

  28. Coding Schemes • A byte provides enough different combinations of 0s and 1s to represent 256 individual characters. • A coding scheme: the defined combinations of 0s and 1s that represent characters by patterns • ASCII(The American Standard Code for Information Interchange) • ASCII represents 0-9, upper and lower case A-Z, and English language punctuation in byte code • EBCDIC (The Extended Binary Coded Decimal Interchange Code) • Unicode

  29. Data Storage Hierarchy DOG….. CAT…. FOX…. File Record DOG, FOUR LEGS, TWO EARS Field DOG Character (byte) D O G Bits 01000100 01001111 01000111

  30. Storage Modes • Direct(Random) Access • records can be retrieved in any order • Faster (nanoseconds) • Usually more expensive • Sequential • records must be retrieved in order • Slower (milliseconds) • Less expensive The dog barked. T H E D O G . . Th bar d og k ed e

  31. Sequential access Method used for tape Reading and writing data consecutively You must forward or rewind the tape to a specific point to access a specific piece of data Much slower Utilized most often for long-term storage and backup Direct access Method used for floppy disks, hard disks, and compact discs Also called random access You can locate a particular data item or file immediately, without having to move consecutively through items stored in front of the desired data item or file Faster Used as the primary method of storage Sequential access versus Direct access

  32. Storage Technologies • Magnetic • Read/write head uses electrical impulses to create or interpret patterns of magnetic impulses • Floppy disks • Hard disks • Tape • Optical • Laser beam creates or reads non-reflective pits and reflective land areas • CDs • DVDs Ancient DecTape systems

  33. Disks Read/Write Head Sector Cluster

  34. Access time The amount of time it takes the device to locate an item on a disk Defines the speed of a disk storage device faster more expensive cost speed slower less expensive Memory (RAM) Hard Disk Compact Disc Floppy Disk Tape

  35. CD-R (compact disc-recordable) You write on the CD-R using a CD recorder or a CD-R drive and special software The CD-R drive can read and write both audio CDs and standard CD-ROMs You cannot erase the disc’s contents Most CD-ROM drives can read a CD-R CD-RW (compact disc-rewritable) An erasable disc you can write on multiple times You must have CD-RW software and a CD-RW drive CD-R & CD-RW

  36. DVD-ROM (digital video disc-ROM) • An extremely high capacity compact disc capable of storing from 4.7 GB to 17 GB • You must have a DVD-ROM drive or DVD player to read a DVD-ROM • Looks just like a CD-ROM but data, instructions, and information is stored in a slightly different manner to achieve a higher storage capacity

  37. A magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost A tape drive reads from and writes data and information on a tape Older computers used reel-to-reel tape drives A tape cartridge is a small, rectangular, plastic housing for tape used in today’s tape drives Used by business and home users to backup personal computer hard disks Both external and internal tape units for personal computers Larger computers use tape cartridges mounted in a separate cabinet called a tape library Magnetic Tapes

  38. Storage techniques used in an enterprise system • Storage area network (SAN): A high-speed network that connects storage devices • Tape library: A high-capacity tape system that works with multiple tape cartridges for storing backups of data, information, and instructions • RAID system: Ensures that data is not lost if one drive fails • Server: Stores data, information, and instructions need by users on the network • CD-ROM jukebox: Holds hundreds of CD-ROMs that can contain application programs and data. Also called a CD-ROM server • Internet backup: Stores data, information, and instructions on the Web

  39. RAID • Redundant array of independent disks • A type of hard disk system that connects several smaller disks into a single unit that acts like a single large hard disk • More reliable than a traditional disk system but quite expensive • RAID duplicates data, instructions, and information to improve data reliability

  40. How does RAID work? Mirroring(RAID Level 1) Striping • Level 1, called mirroring, has one backup disk for each disk • Levels beyond level 1 use a technique called striping, which splits data, instructions, and information across multiple disks in the array

  41. Additional Devices and Media • Memory Cards • A thin, credit card-sized device • Fits into a PC Card slot on a notebook other personal computer • Different types and sizes add storage, additional memory, communications, and sound capabilities to a computer • Three types of PC Card • Advantage of a PC Card for storage is portability between systems • Flash memory • Also called flash ROM or flash RAM • Nonvolatile memory that can be erased electronically and reprogrammed • Stores data and programs on many handheld computers and devices • Flash memory cards store flash memory on removable devices instead of chips

  42. Input and Output Device Driver software Interrupts

  43. Input devices • What is input? • Any data or instructions you enter into the memory of the computer • Users can input data and instructions in a variety of ways • Types of input • Data: A collection of raw unprocessed facts, figures, and symbols • Instructions: Programs, Commands, User responses

  44. Data • Data can be human or machine readable • Data entry converts human readable data into machine-readable form • Data input transfers machine-readable data into the system • Source data automation

  45. Input Devices • Personal computer input devices • Keyboard • Mouse • Voice-recognition devices • Digital cameras • Terminals

  46. Input Devices • Scanning devices • Optical data readers • Bar code scanners • MICR devices • POS (point-of-sale) devices • Pen input devices • Light pens • Touch screens

  47. Output Devices • Monitors • Cathode Ray Tubes (CRTs) • Liquid Crystal Displays (LCDs) • Active matrix • Passive matrix • Printers • Plotters • Computer Output Microform (COM) • Music Devices

  48. Contains a cathode ray tube (CRT), a large sealed, glass screen The screen is coated with tiny dots of phosphor material A pixel, or picture element, is a single point in an electronic image Three dots (red, blue, and green) combine to make up each pixel What is a CRT monitor? cathode ray tube CRT monitor screen

  49. What is a liquid crystal display (LCD) monitor? A type of flat-panel display Uses liquid crystals between two sheets of material to present information on a screen An electric current passes through the crystals which creates the images on the screen

  50. What is display resolution? Describes the sharpness and clearness of an image Resolution of a display device stated as dots, or pixels 800 x 600typically the standard 800 horizontal pixels 1280 x 1024maximum resolution of most monitors 600 vertical pixels 2048 x 1536maximum for high-end monitors Total of 480,000 pixels on screen

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