CHAPER 3 COMPUTER HARDWARE

1
CHAPER 3COMPUTER HARDWARE
2
Learning Objectives

• Identify the major hardware components of a
  computer
• Describe the design and functioning of the
  central processing unit
• Describe the main types of primary and secondary
  storage
• Distinguish between primary and secondary storage
  along the dimensions of speed, cost, and capacity
• Describe the hierarchy of a computer according to
  power and their respective roles
• Differentiate the types of input and output
  technologies and their uses
• Describe what multimedia systems are and what
  technologies they use

3
The Significance of Hardware
Some basic understanding of computer hardware
design and function is essential because firms
(and individuals) frequently must assess their
competitive advantage in terms of computing
capability.
4
Computer Hardware

• The physical equipment used for the input,
  processing, output, and storage activities of a
  computer system
• Central processing unit (CPU) or processor
• Memory (primary and secondary storage)
• Input technologies
• Output technologies
• Communication techniques

5
The Central Processing Unit (CPU)

• a microprocessor is made up of thousands of
  transistors embedded in a circuit on a silicon
  wafer or chip
• Control unit
• Arithmetic-logic unit
• Registers
• stores very small amounts of data and
  instructions for short periods of time

6
Control Unit

• controls the flows of data according to
  instructions.
• Instructions are detailed descriptions of actions
  that should be done during data processing and
  transmission

7
Arithmetic/Logic Unit

• performs the arithmetic calculations and logical
  operations
• Arithmetic operations include addition,
  subtraction, multiplication, and division
• Logical operation are whether one item is
  greater than, less than, or equal to other item
  or 0

8
How the CPU Works?
?DECODE
?EXECUTE
?FETCH
?STORE
9
Machine Cycle

• Instructional cycle
• Fetch
• Decode
• Executive cycle
• Execute
• Store.
• MIPS Machine Instruction cycle per second

10
Computer Speed is determined by

• The preset speed of the system clock
• The word length
• The bus width
• The physical design of the chip
• The line width
• The amount of basic instructions programmed into
  the chip

11
Moores Law

• The transistor densities on a single chip will
  double every 18 months.

12
Advances in Microprocessor Design

• increasing miniaturization of transistors
• making the physical layout of the chips
  components as compact and efficient as possible
• new materials for the chip that improve the
  conductivity (flow) of electricity
• amount of basic instructions programmed into the
  chip
• complex instruction set computing (CISC)
• reduced instruction set computing (RISC)

13
System Unit

• Contains a processor
• In midrange and mainframe computers a cabinet
  with circuit boards
• In PCs - motherboard contains processor chip,
  memory chip, ports, add-in boards interconnecting
  all these components

14
Computer Memory

• Computer memory affects the type of program it
  can run and the work it can do, its speed, and
  both the cost of the machine and the cost of
  processing data. It is use to hold
• Operation system programs
• Application programs
• Data and instructions temporarily (invirtual
  memory )
• Other data and information needed in processing
  in the working storage area

15
Memory capacity

• bits - 0 or 1
• byte - eight-bit string
• kilobyte (KB) - 1,024 bytes (210 bytes)
• megabyte (MB) - 1,048,576 bytes (210 x 210 bytes)
• gigabyte (GB) - 1,073,741,824 bytes (210 x 210 x
  210 bytes)
• terabyte - 1,078,036,791,296 bytes

16
Memory characteristics

• Volatile means that stored data will be lost if
  there is no electricity in the circuits
• Nonvolatile means that stored data will not be
  lost if there is no electricity flowing though
  the medium

17
Registers

• Part of the CPU that store very small amount of
  data and instruction for short periods of time
• High-speed memory area for storing
• temporary results of ALU operations
• Certain control information

18
Primary storage

• Stores for very brief periods of time three types
  of information
• data to be processed by the CPU
• instructions for the CPU how to process the data
• operating system programs that manage various
  aspects of the computers operation
• Tree types of primary storage
• random access memory (RAM)
• cache memory
• read-only memory

19
Secondary storage

• Stores very large amounts of data for extended
  periods of time
• Non-volatile
• Takes much more time to retrieve data
• Can be much more cost effective than primary
  storage
• Can take place on a variety of media, each with
  its own technology

20
Types of Second Storage

• According to the media used for the storage
  device
• Magnetic
• Optical
• According to type of data access
• Sequential
• Direct.

21
Magnetic media

• store data via magnetism
• Sequential access method - Magnetic tape
• Direct access method Magnetic disks
• Hard disk - permanently mounted in a unit that
  may be internal or external to the computer
• Magnetic diskettes (floppy disks) - have much
  less capacity, ranging from 1.44 megabytes for a
  standard high-density disk to 200 megabytes for a
  disk formatted for a zip drive

22
Hard Drive

• A drive a device, which contains a read/write
  unit for a second storage
• Stacks of hard disks are hermetically sealed in
  the hard drive
• Redundant Arrays of inexpensive disks (RAID)
  technology

23
Optical storage devices

• A pinpoint laser beam is used to burn tiny holes
  into the surface of a reflective plastic platter
• Compact disk read-only memory (CD-ROM) -
  high-capacity, low cost, high durability, and
  read only but not written on
• Write once, read many disk (WORM)
• Rewritable CDs - allow the disk to be written
  upon and rewritten up to 1,000 times

24
Computer Hierarchy

• Supercomputer
• has the most processing power
• especially valuable for large simulation models
  of real-world phenomena
• Mainframe Computer
• used in large corporations for centralized data
  processing and maintaining large databases
• allowing for data and information to be shared
  throughout the organization

25
Computer Hierarchy (continued )

• Minicomputers (midrange computers)
• perform the same functions as mainframe computers
  but to a limited extent
• designed to accomplish specific tasks such as
  process control, scientific research, and
  engineering applications
• Workstations
• based on RISC (reduced instruction set computing)
  architecture
• provide both very high-speed calculations and
  high-resolution graphic displays

26
Computer Hierarchy (continued )

• Microcomputers (micros or personal computers,
  PCs)
• Desktop PCs - typical, familiar microcomputer
  system
• Network computers (NCs) are efficient when
• Users work with limited set of programs
• Shared desktops
• Remote user who are difficult to support
• Security is critical.
• Laptop and Notebook Computers - small, easily
  transportable, lightweight microcomputers

27
Desktop or Portable PC The Tradeoffs
28
Computer Hierarchy (continued )

• Palmtop Computer - hand-held microcomputers
• configured for specific applications and limited
  in the number of ways they can accept user input
  and provide output
• Computing Devices - ever-smaller
  computing/communication devices
• Embedded computers
• placed inside other products to add features and
  capabilities

29
Input Technologies

• Human Data Entry Devices allow people to
  communicate with computers
• Source Data Automation technology reduce or
  eliminate the human intervention for data entry.

30
Human Data Entry Devices

• keyboard - designed like a typewriter but with
  many additional function keys
• mice and trackballs - used to point a cursor at a
  desired place on the screen
• touch screens - touch the desired area to trigger
  an action
• joy stick - used primarily at workstations that
  can display dynamic graphics
• microphone - used to dictate to the computer

31
Source Data Automation

• Cash transaction devices
• automated teller machines (ATMs)
• point-of-sale (POS) terminals
• Optical scanners
• bar code scanners
• optical data readers
• optical mark readers
• optical character recognition devices
• Magnetic ink character readers
• Sensors
• Cameras

32
Output Technologies

• Monitors
• Printers
• Voice Output
• Multimedia

33
Monitors

• the video screen used with most computers that
  displays input as well as output
• Cathode tube technology
• Beam of electrons illuminates points on the
  screen
• Liquid Crystal Displays
• Organic oil-like material is placed between two
  polarizers

34
Printers

• impact printers
• like typewriter, using some kind of striking
  action
• non-impact printers
• laser printer - uses laser beams to write
  information
• Ink-jet printer shoots tine dots of ink onto
  the paper
• plotters
• uses computer-directed pens for creating
  high-quality images

35
Output Technologies (continued )

• Voice Output
• can be played through speakers
• Multimedia
• computer-based integration of text, sound, still
  images, animation, and digitized motion video
• Multifunction Devices
• combine a variety of technologies - fax, printer,
  scanner, copy machine, and answering machine

36
Strategic Hardware Issues

• Productivity
• businesses need to assess whether employees
  personal productivity is likely to increase after
  hardware replacement
• Changing Work Styles
• organizations must consider whether new work
  styles will benefit employees and the firm as a
  whole
• New Products and Services
• organizations should consider whether they are
  ready and able to take advantage of the advances,
  and new products and services that hardware may
  make possible for the business
• Improved Communication
• businesses need to judge whether they are ready
  to use multimedia