Transcript Computer Systems

Hardware: Input, Processing,
and Output Devices
Chapter 3
Principles of Information Systems,
Sixth Edition
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Chapter 3 Outline
• Computer Systems: Integrating the Power of
Technology
• Processing and Memory Devices: Power, Speed
and Capacity
– memory characteristics and functions
• Secondary Storage
• Input and Output Devices: The Gateway to
Computer Systems
• Computer System Types, Standards, Selecting
and Upgrading
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Computer Systems:
Integrating the Power of
Technology
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Hardware Components
•1. Processor (CPU)
•2. Memory (primary storage)
•3. Secondary storage
•4. Input devices
•5. Output devices
•6. Communications devices
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How A Computer Thinks: The Processor
•Step 1: Fetch instruction
•Step 2: Decode instruction
•Step 3: Execute the instruction
•Step 4: Store results
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Processing & Memory
Devices
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Processing Characteristics and
Functions
• Machine cycle time is measured in:
– Microseconds (1 millionth)
– Nanoseconds (1 billionth)
– Picoseconds (1 trillionth)
– MIPS (Millions of Instructions Processed per Second)
• 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
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Clock Speed
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Wordlength and Bus Line Width
• Bits (Binary Digits): smallest form of data in a
computer
• Wordlength: number of bits that can be
processed together as a unit. Equal to the size
of the processor’s registers.
• Bus lines: electrical circuits used as central
paths for data flow.
• Bus line width: number of “lanes” on the bus
available for carrying data. Should match word
size.
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Physical Characteristics of the CPU
• Superconductivity - property of certain metals
that allows current to flow with minimal electrical
resistance
• Optical processors - uses light waves instead
of electrical current
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History of Computing: Eniac 5
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Built during WWII: The first electronic computer
Used huge numbers of vacuum tubes.
These often broke down and had to be replaced.
The term “computer bug” comes from the fact
that moths would sometimes get into the
vacuum tube arrays and be the source of some
of the tubes breaking down.
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Semiconductors or Solid State
Electronics
• Using these, Shockley, Bardeen and Brattain
(1947) created the first “solid state” transistor,
essentially an electronically controlled switch,
• Made using semiconductors but much more
durable than a vacuum tube.
• The 2nd generation of computers were the
first to use solid state technology.
• Their Central Processing Units (CPUs) were
built on large scale circuit boards.
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Integrated Circuits
• In 1958, Jack Kilby at Texas Instruments
created the first “Integrate Circuit”, shrinking
the size of the semiconductor transistors.
• Integrated circuits (ICs) make possible the
creation of complex circuits on a single chip.
• The first IC-based microprocessors (“CPU on
a chip”) were manufactured around 1970.
• This led to the creation of the microcomputer.
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Moore’s Law
• Intel’s first microprocessor, the 4004, was
manufactured in 1971, had 4 bit words and 1
kilobyte of primary memory.
• The miniaturization of the integration circuits
has continued at a rapid, more or less
predictable pace since the 1960s.
• Intel’s Gordon Moore, seeing this trend, used
it to predict the no. of possible transistors on
a chip and/or trends in processing power.
• IC technology will eventually be replaced by
some other technology, but should continue
for about 10 years.
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Moore’s Law
Moore’s Law - transistor density/processing power
on an integrate circuit doubles every 18 months
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CISC and RISC
• Complex Instruction Set Computing
(CISC) - places as many microcode
instructions into the central processor as
possible
• Reduced Instruction Set Computing
(RISC) - involves reducing the number of
microcode instructions built into a chip to
an essential set of common microcode
instructions
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memory characteristics and
functions
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Storage Capacity
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Memory Types
•Random Access Memory
(RAM) Types:
–EDO (Extended Data Out)
–DRAM (Dynamic RAM)
–SDRAM (Synchronous
DRAM)
•Read Only Memory (ROM)
Types:
–ROM
–PROM (programmable
ROM)
–EPROM (erasable
programmable ROM)
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Cache Memory
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Multiprocessing
• Speeds processing by linking hundreds and
even thousands of processors to operate at
the same time
• Can coordinate large amounts of data and
access them with greater speed
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Massively Parallel Processing
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Secondary Storage
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Secondary Storage
• Offers the advantages of nonvolatility, greater
capacity, and greater economy
• Access methods, storage capacities, and
portability required are determined by the
information system’s objectives
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Secondary Storage
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Access Methods
• Sequential: records must be retrieved in
order
– Devices used are called sequential access
storage devices (SASD)
• Direct: records can be retrieved in any
order
– Devices used are called direct access storage
devices (DASDs)
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Storage Devices
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Magnetic tapes
Magnetic disks
RAID
Storage area networks (SAN)
Optical disks
Magneto-optical (MO) disks
Digital versatile disks (DVDs)
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Magnetic Disks
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Storage Area Network
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Digital Versatile Disk
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Additional Devices and Media
• Memory cards
• Flash memory
• Expandable storage
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Expandable Storage
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Comparison of Secondary Storage Devices
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Characteristics and Functionality
• 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 - capturing and editing
data at its source
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Input and Output Devices
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Input Devices
• Personal computer input devices
– Keyboard
– Mouse
• Voice-recognition devices
• Digital cameras
• Terminals
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Digital Computer Cameras
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Magnetic Ink Character Recognition
(MICR) Device
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Output Devices
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Display monitors
Printers and plotters
Music devices
Liquid Crystal Displays (LCDs)
– Active matrix
– Passive matrix
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Printers
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Computer System Types,
Standards, Selecting, and
Upgrading
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Computer System Types
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Computer System Types
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Standards
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Standards
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Selecting and Upgrading Computer
Systems
• Hard drive considerations
• Main memory considerations
• Printer considerations
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Example of Price Lists
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Summary
• Hardware - includes any machinery that
assists with the input, processing, and output
activities of a CBIS
• Processing speed - often measured by the
time it takes to complete one machine cycle
• Primary storage (memory) - provides
working storage for program instructions and
data
• Common forms of secondary storage magnetic tape, magnetic disk, compact disk,
digital video disk, and optical disk storage
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Principles and Learning Objectives
• Assembling an effective, efficient computer
system requires an understanding of its
relationship to the information system and the
organization. The computer system objectives
are subordinate to, but supportive of, the
information system and the needs of the
organization.
– DESCRIBE HOW TO SELECT AND ORGANIZE
COMPUTER SYSTEM COMPONENTS TO
SUPPORT INFORMATION SYSTEM OBJECTIVES
AND BUSINESS ORGANIZATION NEEDS
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Principles and Learning Objectives
• When selecting computer devices, you also must
consider the current and future needs of the information
system and the organization. The computer system
objectives are subordinate to, but supportive of, the
information system and the needs of the organization.
– DESCRIBE THE POWER, SPEED, AND CAPACITY OF
CENTRAL PROCESSING AND MEMORY DEVICES.
– DESCRIBE THE ACCESS METHODS, CAPACITY, AND
PORTABILITY OF SECONDARY STORAGE DEVICES.
– DISCUSS THE SPEED, FUNCTIONALITY, AND IMPORTANCE
OF INPUT AND OUTPUT DEVICES.
– IDENTIFY POPULAR CLASSES OF COMPUTER SYSTEMS
AND DISCUSS THE ROLE OF EACH.
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End of Chapter 3
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