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The physical parts of a
 computer system
The physical parts of a computer system
               Computers based on:
1.   Vacuum tube based - c1940s
2.   Transistor based - late 50s; low cost and reliable
     transistors available
3.   Integrated Circuit (IC) based - mid 60s
4.   Large Scale Integrated (LSI) circuit based - c80s; These
     have up to 100,000 transistors on a single chip
5.   Very Large Scale Integrated (VLSI) circuit based - c90s;
     These have >100,000 transistors on a single chip.
           Types of Computers
Small (Microcomputers or Personal computers)
           $500 - $7,000

   Desktop Computers and Workstations

   Laptop Computers
   Notebook Computers
   Palmtop Computers
       Personal Digital Assistant
•   Known as handheld computers
•   PDAs are portable computers taken further
•   Pocket sized designed for use on the move
•   Use a pen as input (write directly to screen)
•   Software 'attempts' to translate handwriting by
    reference to stored prototypes
      Types of Computers (contd.)
   Medium-sized computers (minicomputers)

    - $50,000 - $200,000
    - 3 - 25 times faster than a PC
    - Scaled down mainframe
    - Designed to meet the computing needs of a
    department or small company. Typically 4-100
    concurrent users.
    - Can support a number of concurrent applications and
     often uses a time-sharing operation system that aims
     to keep the users busy.
     Types of Computers (contd.)
   Large or Mainframe Computers
    - $100,000 - $2,000,000
    - 10 - 100 times faster than a PC
- A multi-user computer designed to meet the computing needs of
  a large organization
- Generally refers to computers of the 50s and 60s
- Large number of dumb terminals were used for input/output and
  it had a large number of peripherals attached
- Can process a number of applications concurrently. This is
  known as multi-processing which aims to keep the CPU as
  busy as possible
- Usually housed in special rooms.
      Types of Computers (contd.)
   Superlarge or Supercomputers

-$2 million - $20 million
  -50 - 50,000 times faster than a PC
    - A large number of processors interconnected by a network.
    - Break up gigantic scientific problems into manageable parallel
    - Used to simulate nuclear explosions, ocean flow, to track the
    trajectories of astronomic bodies.
          Computer Operations
   Input – entering data into the computer;
   Processing – performing operations on the
   Output – presenting results;
   Storage – saving data, programs, or output for
    future use;
   Communications – sending or retrieving data
    via the Internet, etc.
Hardware Devices
• Data consists of raw unprocessed facts.
• The applications and users handle them to turn into
• Information is structured, ordered and analyzed data
  useful for decision making. Data is stored in files of
  different types (documents, spreadsheets, databases,
Data Representation
         Digital data - is a
          discrete representation,
          breaking the
          information up into
          separate elements
          (digits, that is 0 and 1)

         How Information Is Stored
   Bit is the smallest unit of data, which denotes
    the binary value of 1 or 0, On/Off, Magnetic/Not
   Byte is the ordered collection of bits
      (eight bits grouped together)
- EBCDIC - Extended Binary Coded Decimal Interchange
  Code (8 bits per byte)
- ASCII - American Standard Code for Information Exchange
  (7 or 8 bits per byte)
Parity bit is the extra bit added to each byte to
 help detect errors
Example: "HI" = 0100100001001001
         (using binary code)
     The Computing Systems
Store, Present, and Help Us Modify:
   Text
   Audio
   Images & graphics
   Video
                  System Unit
   Houses the processing hardware for computer

   Contains:
    - CPU
    - Memory (several types)
    - Interfaces to connect external peripheral
     devices ( such as printer, etc.)
Computer Components

 INPUT                  SECONDARY
DEVICES                  STORAGE

DEVICES                   DEVICES

• The main circuit board, containing computer
  chips and other electronic components, inside
  the system unit to which all computer system
  components connect
  CPU – Central Processing Unit
• The chip located on the motherboard of a
  computer that performs the processing for a
            Multi-core CPUs
• Contain the processing components or cores of
  multiple independent processors on a single
  CPU (allow computers to work simultaneously
  on more tha one task at a time)
              Types of CPU
• Desktop c. – Intel Core i7
            - AMD PhenomII (2-4 cores)
• Workstation, server
             – Intel Xeon
             - AMD Opteron (2,4,6 cores)
• Notebook, Tablet PC
             - Intel Core 2
             - AMD Turion X2 (1, 2,4 cores)
               Computer Time

                                        # PER     COMPARED
      NAME           LENGTH          SECOND     TO 1 SECOND

     Millisecond   .001 second       thousand   15min 40 sec

     Microsecond .001 millisecond    million    11.6 days
     Nanosecond .001microsecond      billion    31.7 years

     Picosecond    .001 nanosecond   trillion   31,700 years

Computer Frequency inversely proportional to computer
         Processing Speed
• CPU clock speed – measurement of the
  processing speed, which is rated in megahertz
  (MHz) or gigahertz (GHz)
• Highter CPU clock speed more instractions can
  be processed per second
• Example: Core i7 3.2 Ghz
            faster than
           Core i7 2.66 GHz
• Chip-based storage
  - primary - amount of the computer's main
  memory (random access memory or RAM)
  - secondary - amount of long-term storage
  available to a computer (computer's hard drive
  or removable storage media)
           Types of Memory
• Cache memory and register – volatite, means
  that their content is rased when power to the
  memory ceases (like RAM)

• Read-only memory (ROM) and flash memory
  - nonvolatite
                 MEMORY SIZE
•   KILOBYTE (K): 210 bytes... 1024 bytes
•   MEGABYTE (MB): 210 KB... “million” bytes
•   GIGABYTE (GB): 210 MB... “billion” bytes
•   TERABYTE (TB): 210 GB... “trillion” bytes
 RAM (Random Access Memory)
• Temporary storage for data, programs and the
  operating system while you are using the PC
• It is volatile, meaning that the contents of memory are
  lost forever when the computer is shut off.
              RAM (contd.)
• Capacity measured in bytes
• Type of RAM that can be installed depends on
- CPU (32-bit CPU – up to 3 GB of RAM,
        64-bit – more than 3 GB)
- Operating system (64-bit version of Windows
  Vista – up to 8 GB, up to 16 or more than 128
  GB, depending on the edition)
     ROM (Read-Only Memory)
• Consists of non-erasable hardware modules that
  store program instructions
• It is non-volatile (that is „read only“)
        Ports and Connectors
• Connectors located on the exterior of the
  system unit that are used to connect external
  hardware devicrs
• Each port attached to the appropriate bus on
  the motherboard
            Storage System
• Storage medium is the hardware where data is
  actually stored (CD, flash memory card)
• Storage device is the type of drive by which
  storage media is read
   - internal (inside the CPU)
   - external (plugged into external port)
  - remote (located on another computer)
            Access Methods
• Random (direct) access, means that data can
  be retrieved directly from any location on the
  storage medium, in any order

• Sequential access, means that the data can be
  retrieved in the order in which it is physically
  stored on the medium
               Hard Drive
• Primary storage system used to store most
  programs and data used with a computer
         Types of Hard Drives
- Magnetic hard drive – a hard drive, consisting of
  one or more metal magnetic disks permanently
  sealed with an access mechanism and
  read/write heads, inside its drive
         Types of Hard Drives
• Solid-state drive (SSD) – a hard drive that uses
  flash memory instead of metal magnetic hard
            Disc Access Time
• The total time that it takes for a hard drive to
  read/write data
• Include three steps:
   - seek time
   - rotational delay
   - data movement time
• Typically it is around 8.5.milliseconds
              Optical Disks
• A type of storage medium read from and written
  to using a laser beam (Example: CD, DVD)
• Advantages:      - large capacity
                   - durability
• Disadvantages: - fragile
                 Optical Drive
• A drive used with optical discs (CD disc, DVD disc)
            Optical Discs
• Read-Only optical disc (CD-ROM, DVD-ROM,
• Recordable optical disc (CD-R, DVD-R,
  DVD+R, BD-R)
• Rewritable optical disc (CD-RW, DVD-RW,
  DVD+RW, BD-Re)
          Optical Disks (contd.)
1) CD-ROM - 700 MB (0.7 GB), single layer, red laser,
  cheap, outdated. For delivering music, software,
  storing data.
2) DVD+-R/RW (Digital Vesatile Disk), 4.7 GB (DVD-5)
  (single-layer), 8.5 GB (DVD-9) (dual-layer), 9.4 GB
  (double-sided disk), red laser, current, cheap. For
  software, movies, data.
3) Blu-Ray, 25 GB (single layer), 50 GB (double-layer),
  may support up to 6-8 layers in the future, blue laser,
  quite expensive. For high-definition movies, HDTV,
4) HVD (Holographic Vesatile Disk) - 3.9 TB, 2 lasers,
  very expensive, emerging.
 Other Types of Storage System
• Flash memory – a chip-based storage medium
  that store data using electrons
• Flash memory card – a small , rectangular flash
  memory medium (such as CompactFlash)
 Other Types of Storage System
• Holographic storage – the type of three
  dimension (3D) storage system that uses
  multiple blue laser beams to store data in three
• Advantages: - speed
              - capability
              - convenient for rarely changed data
 Other Types of Storage System
• Magnetic tape – storage media consisting of
  plastic tape with a magnetizable surface that
  store data as a series of magnetic spot
• Advantages: - low cost per megabyte
 Other Types of Storage System
• RAID (redundant arrays of independent disks)
a storage method that uses several hard rives
  working together
• Purpose: - to increase perfomance
          - to protect critical data on storage
  server (to increase fault tolerance)
• Techniques: - disc stripping
               - disc mirroring

• Electronic path over which data can travel
• Bus width is the number of wires in the bus
  over which data can travel, affects the number
  of bits being transmitted at one time
• Throughput or bandwidth is the amount of
  data that can be transferred via the bus in a
  given time period
Input Devices
• An input device containing numerous keys that
  can be used to input letters, numbers, and
  other symbols
    Pointing and Touch Devices
• An input device that moves an on-screen
  pointer to allow the user to select objects on
  the screen
• Types: - mouse
        - pen/styluses
        - touch screens
• An input device that reads printed text and
  graphics and transfers them to a computer in
  digital form
   Speech Recognition System

• Speech recognition systems
• Music input systems
         Music Input System
• Used to input music into a computer
Output Devices
• Quality mesured by dots per inch (dpi)
Speed measured in pages per minute (ppm)
• Types: - laser printers (use toner powder)
          - ink-jet printers (use liquid ink)
          - special purposes printers
  (photoprinter, 3D printer)
3D Printing
       Display Devices (Monitor,
            Display Screen)
• CRT monitors
• Flat-panel displays: - liquid crystal displays (LCD)
                    - plasma displays
• Organic light emmiting diode (OLED) displays
      Display Devices (contd.)
• Pixels – the smallest colorable area in an
  electronic image
• Screen resolution affects the amount of
  information (in pixels) displayed on the screen
                Video Card
• Installed inside computer or directly into the
  motherboard (in graphic processing unit GPU)
• Detrmins the graphic capabilities of the
Audio Output