David Harris

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Computer Hardware

• Summary
• Slides

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Summary

• Major types uses of microcomputer, midrange,
  mainframe computer systems
• Hardware components functions
• Computer Peripherals
• Storage

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Computer System Categories
single user systems
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Microcomputers

• 1975, ALTAIR, flicking switches
• 1977, Commodore and Radio Shack produce personal
  computers
• 1979, Apple computer, the fastest selling PC so
  far
• 1982, IBM introduces the PC which changes the
  market

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Moores Law
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Microcomputer Systems

• Personal Computer (PC)
• microcomputer for use by an individual
• Desktop fit on an office desk
• Laptop small, portable PC
• Workstation a powerful, networked PC for
  business professionals
• Network Server more powerful microcomputers
  that coordinate telecommunications resource
  sharing in small networks

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Recommended features for PC
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How corporate buyers choose PCs

• Solid performance at a reasonable price
• Operating system ready
• Connectivity reliable network interface or
  wireless capability

TCO - Total Cost of Ownership
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Terminals

• Devices that allow access to a network
• Dumb terminals keyboard video monitor with
  limited processing
• Intelligent terminals modified networked PCs or
  network computers
• Network terminals or computers
• Windows terminals depend on network servers for
  software, processing and storage
• Internet terminals depend to the Internet or
  Intranet for operating systems and software

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Network Computers

• Used by Workers in Networks
• Sealed Low-Cost Systems
• Network Microcomputers
• No or Minimal Disk Storage
• Dependent on networks for Operations
• Standardization
• Reduced Costs of Maintenance Upgrades

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Information Appliances

• Hand-held microcomputer devices
• Personal digital assistants (PDA)
• BlackBerry
• Video-game consoles (Xbox)
• Internet enabled cellular phones
• Advantages
• specific functionality provided by vendor
• more secure
• Disadvantage
• Not generative (only functions approved by vendor)

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Midrange systems

• High-end network servers
• Minicomputers for scientific research
  industrial process monitoring
• Less costly to buy, operate maintain than
  mainframe

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Mainframe Computer Systems

• Large, fast powerful computer systems
• Large primary storage capacity
• High transaction processing
• Complex computations
• Can be used as superservers for large companies

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Supercomputer Systems

• Extremely powerful systems
• Scientific, engineering business applications
  at extremely high speeds
• Global weather forecasting, military defense
• Parallel processing with thousands of
  microprocessors
• Billions of operations per second
• Millions of dollars
• Minisupercomputers costing hundreds of thousands
  of dollars

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The Computer System Concept
Central Processing Unit
Control Unit
Arithmetic Logic Unit
Input Devices
Output Devices
System Bus
Special Purpose Processors
Primary Storage Memory
Cache Memory

• Keyboard
• Mouse
• Touch Screen
• Optical-Scanner
• Voice Recognition
• etc.

• Visual Display Unit
• Printer
• Audio-Response
• Physical Control Devices, etc.

Secondary Storage Devices
Magnetic Disk Tape Units Optical Disks, etc.
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Master Slave
Mainframe
Controller
Dumb Terminal
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Peer to Peer
Computer
Computer
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Client Server
Server
Client
Multi-user
Single user
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Storage tradeoffs
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Semiconductor memory

• Used for primary storage
• Small size, fast, shock/temperature resistance,
  but volatile
• RAM random access memory
• ROM read only memory - firmware

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Magnetic Disks

• Used for secondary storage
• Fast access and high storage capacity

Source Quantum.
Source Corbis.
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Direct and Sequential Access

• Direct Access or Random Access
• Directly store retrieve data
• Each storage position has unique address can be
  accessed in same length of time
• Semiconductor memory chips, magnetic disks
• Sequential Access
• Data is stored retrieved in a sequential
  process
• Must be accessed in sequence by searching through
  prior data
• Magnetic tape

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Direct and sequential access
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Flash drive

• New type of permanent storage
• Uses semiconductor memory
• Small chip with thousands of transistors
• Easily transported
• Also called jump drives, USB flash drives

Source Courtesy of Lexar Media.
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The End