Inside The Computer

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Chapter 2

• Inside The Computer
• Notes Source
• http//www.webopedia.com
• http//en.wikipedia.org

2
Learning Objective

• Differentiate between hardware and software
• Terms for data storage and transfer
• Physical connections
• Parts of system unit
• Components of motherboard
• How CPU works
• Factors determine microprocessor performance
• Types of memory
• Types of expansion bus
• Difference between analog and digital
  representation of data

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2.1 Hardware vs. Software

• Simple way hardware is physical, you can touch
  it, tangible
• Ex keyboard, mouse, monitor.
• Software is the instruction that tell computer
  what to do, you cannot touch it, intangible
• Ex
• Operating System ( Windows, Linux, etc)
• Application ( Office, Multimedia, etc)

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Macs and PCs

• PCs Personal Computer
• IBM
• Compatibles
• Clones
• Use Intel or AMD processors
• Macs Apple Macintosh computers
• Apple
• First GUI
• Motorola Processors

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• PC Short for personal computer or IBM PC. The
  first personal computer produced by IBM was
  called the PC, and increasingly the term PC came
  to mean IBM or IBM-compatible personal computers,
  to the exclusion of other types of personal
  computers, such as Macintoshes. In recent years,
  the term PC has become more and more difficult to
  pin down. In general, though, it applies to any
  personal computer based on an Intel
  microprocessor, or on an Intel-compatible
  microprocessor. For nearly every other component,
  including the operating system, there are several
  options, all of which fall under the rubric of PC

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• MAC A popular model of computer made by Apple
  Computer. Introduced in 1984, the Macintosh
  features a graphical user interface (GUI) that
  utilizes windows, icons, and a mouse to make it
  relatively easy for novices to use the computer
  productively. Rather than learning a complex set
  of commands, you need only point to a selection
  on a menu and click a mouse button. Moreover, the
  GUI is embedded into the operating system. This
  means that all applications that run on a
  Macintosh computer have a similar user interface.
  Once a user has become familiar with one
  application, he or she can learn new applications
  relatively easily. The success of the Macintosh
  GUI led heralded a new age of graphics-based
  applications and operating systems. The Windows
  interface copies many features from the Mac.

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Describing Hardware Performance

• Bits and Bytes
• Bits
• Binary Digit
• 0/1
• Measure data transfer rate
• Byte
• 8 bits
• Store a single character
• Measure memory
• Thousand, Millions, and More
• 1000
• Kilo, K, KB, Kbps
• 1,000,000
• Mega, M, MB, Mbps
• 1,000,000,000
• Giga, G, GB, Gbps
• 1,000,000,000,000
• Tera, T, TB, Tbps

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2.2 Introducing the System Unit

• 2.2.1 Outside of the Box
• Power Switch
• Connectors
• Male/female
• Peripheral devices arent absolutely essential
  for the computer ability to function
• Expansion card/slot
• Video adapter
• Network
• PC card
• Sound card
• Port
• Serial not require fast data transfer (1 bit at
  a time)
• USB support plug and play
• 1394 very fast
• IrDA wireless infrared
• Parallel 8 wires, high speed connection
  -printer
• PS/2 mouse
• SCSI usually on Macs

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• 1394 A very fast external bus standard that
  supports data transfer rates of up to 400Mbps (in
  1394a) and 800Mbps (in 1394b). Products
  supporting the 1394 standard go under different
  names, depending on the company. Apple, which
  originally developed the technology, uses the
  trademarked name FireWire. Other companies use
  other names, such as i.link and Lynx, to describe
  their 1394 products
• IrDA Short for Infrared Data Association, a group
  of device manufacturers that developed a standard
  for transmitting data via infrared light waves.
  Increasingly, computers and other devices (such
  as printers) come with IrDA ports. This enables
  you to transfer data from one device to another
  without any cables. For example, if both your
  laptop computer and printer have IrDA ports, you
  can simply put your computer in front of the
  printer and output a document, without needing to
  connect the two with a cable.
• SCSI (skuze) Short for small computer system
  interface, a parallel interface standard used by
  Apple Macintosh computers, PCs, and many UNIX
  systems for attaching peripheral devices to
  computers. Nearly all Apple Macintosh computers,
  excluding only the earliest Macs and the recent
  iMac, come with a SCSI port for attaching devices
  such as disk drives and printers. SCSI interfaces
  provide for faster data transmission rates (up to
  80 megabytes per second) than standard serial and
  parallel ports. In addition, you can attach many
  devices to a single SCSI port, so that SCSI is
  really an I/O bus rather than simply an
  interface.

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• Front Panel
• Power Switch
• Reset Switch
• Drive Light
• Power Light

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• 2.2.2 Inside the System Unit
• Motherboard
• Power Supply
• Cooling Fan
• Internal Speaker beep
• Drive Bays
• Whats on motherboards
• Integrated Circuit chip that emulate thousand
  or million of transistors.
• Act as electronic switch route data in
  different ways according to software instructions
• Others on motherboards
• System Clock
• -ticks control processing speed

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Others on motherboard ..cont..

• The Microprocessor
• CPU interprets instruction given by software
• Control unit is one of the CPU components
  coordinates and control other components
• Processing Cycles
• Instruction cycle
• Execution cycle
• ALU perform arithmetic and logic functions
• Registers

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Processing Cycles

• The time period during which one instruction is
  fetched from memory and executed when a computer
  is given an instruction in machine language.
  There are typically four stages of an instruction
  cycle that the CPU carries out
• 1. Fetch the instruction from memory. This step
  brings the instruction into the instruction
  register, a circuit that holds the instruction so
  that it can be decoded and executed.
• 2. Decode the instruction.
• 3. Read the effective address from memory if the
  instruction has an indirect address.
• 4. Execute the instruction.
• Steps 1 and 2 are called the fetch cycle and are
  the same for each instruction. Steps 3 and 4 are
  called the execute cycle and will change with
  each instruction.

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The Microprocessor cont..

• Performance
• Data Bus Width and Word Size
• The larger, the faster
• Pipelining
• Executing more than one instruction per
  instruction cycle
• CISC/RISC
• RISC generally faster
• Math coprocessor
• Speed up computations
• Chips
• Pentium II, III, Celeron, Zeon
• Apple G3 / G4
• AMD Athlon
• Parallel Processors
• Where multiple chips working simultaneously

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Pipelining
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pipelining

• A technique used in advanced microprocessors
  where the microprocessor begins executing a
  second instruction before the first has been
  completed. That is, several instructions are in
  the pipeline simultaneously, each at a different
  processing stage. The pipeline is divided into
  segments and each segment can execute its
  operation concurrently with the other segments.
  When a segment completes an operation, it passes
  the result to the next segment in the pipeline
  and fetches the next operation from the preceding
  segment. The final results of each instruction
  emerge at the end of the pipeline in rapid
  succession.

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RISC/ CISC

• A complex instruction set computer (CISC) is a
  microprocessor instruction set architecture (ISA)
  in which each instruction can execute several
  low-level operations, such as a load from memory,
  an arithmetic operation, and a memory store, all
  in a single instruction.
• The reduced instruction set computer, or RISC, is
  a CPU design philosophy that favors a reduced
  instruction set as well as a simpler set of
  instructions

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Co-Processor

• A special-purpose processing unit that assists
  the CPU in performing certain types of
  operations. For example, a math coprocessor
  performs mathematical computations, particularly
  floating-point operations. Math coprocessors are
  also called numeric and floating-point
  coprocessors. Most computers come with a
  floating-point coprocessors built in. Note,
  however, that the program itself must be written
  to take advantage of the coprocessor. If the
  program contains no coprocessor instructions, the
  coprocessor will never be utilized.
• In addition to math coprocessors, there are also
  graphics coprocessors for manipulating graphic
  images. These are often called accelerator
  boards.

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Memory

• Non Volatile
• ROM BIOS
• Booting
• CMOS
• Stores BIOS settings
• Setup program can change settings
• Volatile
• RAM
• Cache

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Input /Output (I/O) Buses

• Slot/cards connect motherboard to peripherals
• Standards
• PCI Peripheral Component Interconnect -supports
  Plug and Play
• ISA Industry Standard Architecture - older,
  still common
• AGP Accelerated Graphics Port - fast video

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How Computers Represent Data

• Digital
• Counts in discrete units
• General purpose computers
• Analog
• Measures in continuous stream
• Special purpose computers

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How Computers Represent Data ..cont..

• Representing Numbers
• Binary base 2, computer internal number
  representation
• Hexadecimal base 16, easier for humans than
  binary
• Representing Very Large and Very Small Numbers
• Floating Point Notation
• A floating-point number a can be represented by
  two numbers m and e, such that
• a m be.
• (1.20 10-1) (1.20 10-1) (1.44 10-2)
• In a fixed-point system with the decimal point at
  the left, it would be
• .120 .120 .014
• Representing Characters
• Codes
• ASCII most PCs
• EBCDIC IBM mainframes
• Unicode expanded to cover all languages
• Parity extra bit that holds information on sum
  of other bits, to provide error-checking

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• EBCDIC Abbreviation of Extended Binary-Coded
  Decimal Interchange Code. Pronounced eb-sih-dik,
  EBCDIC is an IBM code for representing characters
  as numbers. Although it is widely used on large
  IBM computers, most other computers, including
  PCs and Macintoshes, use ASCII codes.
• UNICODE A standard for representing characters
  as integers. Unlike ASCII, which uses 7 bits for
  each character, Unicode uses 16 bits, which means
  that it can represent more than 65,000 unique
  characters. This is a bit of overkill for English
  and Western-European languages, but it is
  necessary for some other languages, such as
  Greek, Chinese and Japanese. Many analysts
  believe that as the software industry becomes
  increasingly global, Unicode will eventually
  supplant ASCII as the standard character coding
  format.

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PARITY BIT

• In computing and telecommunication, a parity bit
  is a binary digit that indicates whether the
  number of 1 bits in the preceding data was even
  or odd. If a single bit is changed in
  transmission, the message will change parity and
  the error can be detected at this point. (Note
  that the bit that changed may have been the
  parity bit itself!) The most common convention,
  or parity scheme, is that a parity bit of 1
  indicates that there is an odd number of ones in
  the data, and a parity bit of 0 indicates that
  there is an even number of ones in the data

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Memory vs. Storage

• Memory
• Temporary (volatile) workspace
• Like desktop
• Storage
• Semi-permanent storage
• Like file cabinet
• Data held in files
• Files grouped in directories / folders

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2.3.1 Why Is Storage Necessary?

• Compared to memory, storage is
• Non volatile
• Cheaper
• Larger
• Able to help with starting applications
• Cheap enough to replace paper storage

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Types of Storage Devices

• Read/Write Media vs. Read-Only Media
• Read/Write most devices
• Read-Only CD-ROM, DVD-ROM
• Sequential vs. Random Access Storage
• Sequential -slow but inexpensive
• Faster- more expensive
• Storage Technologies Magnetic and Optical
• Magnetic
• Electromagnetic read/write head changes
  electrical signal to magnetic fields and
  vice-versa
• Most common technology for PC storage
• Almost read/write
• Optical
• Laser read pits on disk
• Magneto Optical
• Combines for maximum storage capacity

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Random Access Storage

• A direct access storage device, or DASD is a form
  of magnetic disk storage, historically used in
  the mainframe and minicomputer (mid-range)
  environments. A redundant array of independent
  disks (RAID) is a form of DASD.
• "Direct access" means that all data can be
  accessed directly in a form of indexing also
  known as "random access" as opposed to storage
  systems based on seeking sequentially through the
  data (e.g., tape drives).

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Magnetic storage

• Magnetic storage is a term from engineering
  referring to the storage of data on a magnetised
  medium. Magnetic storage was first suggested by
  Obeline Smith in 1888. The first magnetic
  recorder was invented by Valdemar Poulsen in
  1895.
• The read/write heads in magnetic storage record
  data in the form of magnetized spots on iron
  oxide coatings.
• Media types that exploit magnetic storage include
  hard disk and floppy disk drives, zip drives and
  various tape drives, video cassettes and audio
  cassettes, magnetic core memory, thin film memory
  and drum memory.

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Optical Storage

• Optical Storage is made possible by data storage
  devices such as optical discs and holographic
  storage systems. This is different from other
  types of storage mediums that may use a magnetic
  surface (e.g. magnetic tape storage, a hard disk
  or floppy disk) or electical charges (e.g. flash
  memory).

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magneto-optical

• A magneto-optical drive is a kind of optical disc
  drive capable of writing and rewriting data upon
  a magneto-optical disc. Both 5.25" and 3.5" form
  factors exist. The technology was introduced at
  the end of the 1980s. Although optical, they
  appear as hard drives to the operating system and
  do not require a special filesystem (they can be
  formatted as FAT, NTFS, etc.).

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2.3.2 The Storage Hierarchy

• Online or Primary
• Hard Disk
• Near-online
• Secondary
• Floppies, CD-ROMS
• Offline
• Tertiary or archival
• Magnetic tapes

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Speed of Storage Devices (Access Time)

• Access time total amount of time to begin
  reading data
• Seek time time just to locate data
• SDDs (solid state disks)
• Speed of memory
• Permanence of disks
• Expensive
• A solid state drive (SSD, also called solid state
  disk) is a data storage device that uses
  non-volatile memory (NAND) such as flash, or
  volatile memory such as SDRAM, to store data,
  instead of the spinning platters found in
  conventional hard disk drives. While not
  technically "disks" in any sense, these devices
  are so named because they are typically used as
  replacements for disk drives in situations where
  conventional drives are impractical.

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Access time

• Access time is the time delay or latency between
  a request for access to an electronic system, and
  the access being granted or the requested data
  returned.
• In magnetic disk drives, it is the time for the
  access arm to reach the desired track and the
  delay for the rotation of the disk to bring the
  required sector under the read-write mechanism.

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Seek time

• Seek time is one of the several delays associated
  with reading or writing data on a computer's disk
  drive. The others are rotational delay and
  transfer time. In order to read or write data in
  a particular place on the disk, the read/write
  head of the disk needs to be moved to the correct
  place (just as to play a particular song on a
  cassette of recorded music, the tape needs to be
  wound to the right place). This process is known
  as "seeking", and the time it takes for the head
  to move to the right place is the "seek time".
  Seek time for a given disk varies depending on
  how far the head's destination is from its origin
  at the time of each read or write instruction
  usually one discusses a disk's average seek time.

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2.3.3 Floppy Disks and Floppy Disk Drive

• Floppy
• earlier floppy disks were flexible, now internal
  media still flexible
• Storage Capacity
• Relatively small, but advantage of portability
• Protect Data
• Avoid magnet, touching media directly, smoke,
  food/drink, humidity, high temperatures
• Use write-protect tab
• Floppy Disk Drives
• Drive A on PC Windows desktop, may be external
  on notebooks
• Circular track, wedge-shaped sectors store files
• FAT matches files to track-sector locations
• Formatting
• Creates tracks and sectors

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Beyond the Floppy High Capacity Disks and Drives

• Floppy-size and removable
• High capacity
• Require special drives/disks
• Drive also handle regular floppies
• SuperDisk
• Also known as the LS-120 and the later variant
  LS-240, the SuperDisk was introduced by 3M's
  storage products group (later known as Imation)
  circa 1997 as a high-speed, high-capacity
  alternative to the 90 mm (3.5 in), 1.44 MB floppy
  disk.
• HiFD
• The Sony HiFD (High capacity Floppy Disk) was an
  attempt by Sony to replace their own aging 3.5
  inch floppy disk, which had proven successful in
  the mid-80's war to replace the 5.25 inch floppy
  disk.
• Drive will not handle regular floppies
• Zip
• The Zip drive is a medium-capacity removable disk
  storage system, introduced by Iomega in late
  1994. Originally it had a capacity of 100 MB, but
  later versions increased this to first 250 MB and
  then 750 MB.

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2.3.4 Hard Disks

• Several hard fixed disks (platters) stacked
  vertically and sealed in a case
• Why Needed?
• Modern OS and application take much more memory
• Users data even more memory
• How it works?
• Like floppies but read/write head doesnt touch
  platter
• Head crash can create bad sectors
• Can be partitioned to use multiple operating
  systems
• Factors Affecting Hard Disk Performance
• Position seek time
• Transfer spindle (rotational) speed
• Latency time to find sector after track is
  found
• Hard Disk Interfaces
• Most common IDE
• Newer, faster, more expensive - SCSI

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Hard Disks ..cont..

• Disk Cache
• To improve hard disks performance
• RAM that stores recently-used information from
  disk
• Reduced need to access drive
• RAID
• Redundant Array of Inexpensive Disks
• Provide backup of all data by mirroring /
  duplexing data
• Provide fault tolerance in case of failure
• Used by businesses and web sites
• Stripping related data across disks improves
  access time (shorterns head movements)
• Removable Hard Disks
• Useful for archiving and backup

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Magnetic Tape

• Sequential
• Slow Access
• Inexpensive
• Appropriate for archiving mass data that is
  infrequently accessed
• Digital tape can be fast accessed and higher
  capacity, but more expensive

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• CD-ROM Discs and Drives
• Read only
• Widely varied data transfer 2X,4X.20X
• Usually play audio CDs and Photo CDs
• May be mounted in multi-disc jukeboxes for
  networks
• CD-R and CD-RW Discs and Recorders
• CD-R
• Read CD-ROM, CD-R, or CD-RW discs
• Write once only to CD-R discs
• Inexpensive
• CD-RW
• Read CD-ROM, CD-R, or CD-RW discs
• Write once only to CD-R discs
• Write multiple times to CD-RW discs
• Relatively expensive

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• DVD-ROM Discs and Drives
• Same as CD-ROMs except
• Higher storage capacity
• Higher data transfer rate
• Also read CD-ROM
• More optical Storage Technologies
• WORM (write once, read many) larger discs
• WORM means Write Once, Read Many (or Write Once
  Read Multiple times). It is sometimes used when
  discussing computer storage media that can be
  written to once, but read from multiple times.
• Magneto-optic discs

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Storage Horizon

• FMD-ROM
• Multilayer CDs with huge storage capacity
• Fluorescent Multilayer Disc (FMD), is an optical
  disc format developed by Constellation 3D that
  uses fluorescent, rather than reflective
  materials to store data. Reflective disk formats
  (such as CD and DVD) have a practical limitation
  of about two layers, primarily due to
  interference, scatter, and intra-layer cross
  talk. However, the use of fluorescence allows
  FMDs to have up to 100 layers. These extra layers
  allow FMDs to have capacities up to a terabyte,
  while maintaining the same physical size of
  traditional optical disks.
• Storage Area Network (SAN)
• Connect high-capacity storage to all
• servers on a network

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2.4 Understanding Input Not Just Data Entry

• 4 types of input
• Software
• Inputs applications and data files
• Data
• Input by user
• Commands
• To computer from user
• Responses
• From users to computer messages

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Input Devices The Computers Senses

• Keyboard
• Cabled or wireless
• Keypress causes computer to display character at
  cursor location / insertion point
• Using Computer Keyboard
• Like typewriter except
• Enter
• Tab
• Cursor Movement
• Numeric Keypad
• Windows
• Del
• Etc..

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Keyboard ..cont..

• Alternative Keyboards
• QWERTY
• Standard
• Dvorak
• Incorrectly believed to allow faster typing by
  better key arrangement
• Entering International Characters
• dead keys add marking to next letter typed
• Health Risks of Keyboard Use
• Cumulative trauma disorder (CTD) or repetitive
  strain injury (RSI)
• Ergonomic keyboards may help

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QWERTY

• QWERTY (pronounced /'kw?ti/) is the most common
  modern-day keyboard layout on most English
  language computer and typewriter keyboards. It
  takes its name from the first six letters seen in
  the keyboard's top row of letters. The QWERTY
  design was patented by Christopher Sholes in 1868
  and sold to Remington in 1873, when it first
  appeared in typewriters.

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Dvorak

• The Dvorak Simplified Keyboard (pronounced
  /'dvoræk/) is a keyboard layout designed by Dr.
  August Dvorak and William Dealey in the 1920s and
  1930s as an alternative to the more common QWERTY
  layout. It has also been called the Simplified
  Keyboard or American Simplified Keyboard, but is
  commonly known as the Dvorak keyboard.

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dead key

• A dead key is a key on a typewriter or a computer
  keyboard that produces no output when it is
  pressed, but modifies the output of the next key
  pressed after it.
• For example, if a keyboard has a dead key "",
  the French character e accent aigu (é) can be
  generated by pressing first "", then "e".

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• Repetitive strain injury, also called repetitive
  stress injury or typing injury, is an
  occupational overuse syndrome affecting muscles,
  tendons and nerves in the arms and upper back. It
  occurs when muscles in these areas are kept tense
  for very long periods of time, due to poor
  posture and/or repetitive motions.

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• Speech Recognition
• Also called voice recognition
• Converts voice input into characters
• Pointing Devices
• Move a pointer in GUI system
• Draw, paint or write
• Most common, mouse
• Types of Mice
• PS/2, serial, usb, cordless
• Mechanical (ball), Optical (laser),
• Wheel (for scroll)
• Health Risks of Mouse Usage
• CTD/RSI - Cumulative Trauma Disorder/Repetitive
  Stress Injury
• Alternatives
• Foot mouse, trackballs, pointing sticks, touchpad
  
• More Ways to Control Computer
• Joystick
• Touchscreen kiosk
• Pen computing with PDAs

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2.5 Device

• Sound Cards
• Digitize sound
• Record and Playback
• MPEG data compression
• Video Capture Boards
• Web cams
• Videoconferencing
• MPEG data compression
• Digital Cameras
• Take picture in digital format
• Scanners
• Digitize from source document on paper
• OCR (Optical Character Recognition) changes
  picture file to characters.
• FAX
• Sends faxes directly on computer
• Need special software and modem

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• Sound Card A typical sound card includes a sound
  chip usually featuring a digital-to-analog
  converter that converts recorded or generated
  digital waveforms of sound into an analog format.
  This signal is led to a (earphone-type) connector
  where a cable to an amplifier or similar sound
  destination can be plugged in.

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Input Devices in Business, Industry and Science

• Source data automation
• Collect transaction information at its source
• Image processing of documents
• Magnetic-ink character recognition (MICR) bank
  checks
• Bar Code Reader
• Mark Sense Character Recognition- Scantrons for
  exams
• Biological Feedback Devices
• Translate biological changes into computer input
• Eye-gaze response
• Virtual reality- responds to body movements by
  changing virtual world
• Brain wave changes- experimental
• Chemical Detectors
• smell explosives, narcotics, toxins, etc..

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Understanding Output Making Data Meaningful

• Visual Display System
• Video adapter board / video RAM (VRAM) control
  the
• Resolution number of dots on the screen
• VGA - 640x480
• Super VGA (SVGA) 1024x768
• Color Depth maximum number of colors
• Refresh rate higher flicker reduction
• The refresh rate (or "vertical refresh rate",
  "vertical scan rate" for CRTs) is the number of
  times in a second that a display is illuminated.

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Understanding Output ..cont..

• Monitor /Display
• Provide soft copy (vs hard copy from printer)
• Types
• CRT (cathode ray tube) like TV
• Flat panel display
• Monochrome
• Color
• Screen Size
• Diagonal Measure

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Understanding Output ..cont..

• Data Projectors
• Project video output onto screen for an audience
• LCD
• Less expensive
• Less sharp image
• A liquid crystal display (LCD) is a thin, flat
  display device made up of any number of color or
  monochrome pixels arrayed in front of a light
  source or reflector.
• DLP (digital light processing)
• More expensive
• Image sharp enough for large screen and bright
  room
• Digital Light Processing (DLP) is a technology
  used in projectors and video projectors.
• Headset
• Projects image onto screen for individual wearing
  special headset
• CAVE (Cave Automated Virtual Environment)
  projects image onto 3D glasses
• Used for virtual reliaty

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Understanding Output ..cont..

• Printers
• Provide hard copy
• Types
• Impact
• Line printers
• Letter quality
• Dot Matrix
• Near letter quality
• Non-impact
• Inkjet/bubble jet
• Least expensive non-impact
• Laser
• Network
• Personal
• Color
• expensive

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Understanding Output ..cont..

• Plotters
• Used for maps, blueprints, etc..
• Fax Output
• Receives faxes directly from computer
• Need special software and modem
• Audio Output
• Sound cards and speaker
• Tactile Feedback
• Virtual reality stimulation of sense of touch

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Thank You