Information Systems A Business Approach

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Information SystemsA Business Approach

• Hardware Fundamentals

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Computer Memory

• 1 byte (8 binary digits) -1 alphanumeric
  character
• 1 Kilobyte (KB) 1024 Bytes (210) - One half of a
  double spaced page of A4
• 1 Megabyte (MB) 1,048,576 Bytes (220)- 500 pages
  of A4
• 1 Gigabyte 1,073,741,824 (230) - Half a million
  pages of A4
• Most people think of a KB as 1000 bytes

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Computer Speed

• Computer speeds are defined in two ways
• The speed of the system clock usually quoted in
  Megahertz (cycles per second)
• We quote speeds in millions of instructions per
  second (MIPS)
• The problem is that clock speed does not
  necessarily equate to instruction process rate
• To give an idea of the number crunching ability
  of a processor, a third metric FLOPS (Floating
  point operations per second) is used
• Key Concept - Most business applications do not
  require vast amounts of number crunching. Instead
  they are input output focused. Accordingly disk
  access speeds and internal transfer rates are
  more important than raw processor power

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Four Generations Of Hardware

• Generation 1Valves - 1946-1959 Transforming
  Business Processes
• Generation 2 Transistors - 1959-1964
  Transforming Organisations
• Generation 3 Integrated Circuits 1965-1971,
  Transforming Markets
• Generation 4 Very Large Scale Integration (VLSI)
  1971- present day - Transforming Society

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Types Of Computer

• Super computer
• Mainframe
• Mini computer
• Workstation
• Microcomputer
• Handheld
• Wearable

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Computer Architecture

• Most computers use a single processor
  architecture called the vonNeumann architecture
• The program and data are stored in memory and
  fetched in as required
• All computers perform the same basic functions
• input
• output
• Processing
• storage

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PC Architecture

• Based on the vonNeuman machine, the PC has the
  following features
• motherboard with expansion slots
• processor (divided into the ALU and control unit)
• primary memory (divided into RAM ROM)
• secondary storage (hard floppy drives)
• system bus
• ports (serial, parallel, USB, Starfire)

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A Conceptual view of the system unit
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The Simplified Machine Cycle
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Types Of Chip

• The most widely used type is a complex
  instruction set chip (CISC) which are used in IBM
  PC standard systems
• The other variety of chip is a reduced
  instruction set chip(RISC) and is able to replace
  complicated instructions in terms of a number of
  simple instructions
• These tend to be used in workstation and Apple
  machines

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The Quest For Speed

• New materials (gallium arsenide)
• New architectures (parallel machines)
• Reversion to vacuum tubes (nano scale)
• New technology such as quantum computing would
  allow all the numbers from 0 to one trillion to
  be represented using a mere 40 qubits compared
  with 104 trillion bits in a conventional machine

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Output Devices

• Hard copy (printers)
• Soft copy monitors
• Monitors can be CRT or Flat screen (LED) or more
  recently OLED
• Monitor clarity (resolution) depends on the
  number of pixels and their density on the screen
• A high quality video card will improve pc
  performance substantially

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Primary Storage

• ROM - (firmware) holds instructions permanently
• Also have PROM and EEPROM chips for embedded
  software. (important for hand helds)
• RAM - holds data and instructions while there is
  power, RAM is volatile
• The more memory the PC has the better it will
  perform
• 128MB is average. Good design puts the RAM close
  to the processor. Accessing RAM is many thousand
  times faster than accessing secondary storage.

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Secondary Storage

• Classified by access method
• Serial - tapes, DAT etc. are too slow for live
  systems and tend to be used for system backups
• Random - hard drives are much faster than devices
  such as floppy drives, CD, DVD, ZIP drives etc.
• Random devices such a flash memory are random
  access but use EEPROMs to store user data
• Widely used in hand helds and digital cameras -
  expensive and slower than most hard drives and
  expensive

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Moores Law

• In 1965, Gordon Moore, one of the cofounders of
  Intel noted that the amount of information
  storable on a square inch of silicon would double
  about every 18 months (Gordon and Gordon, 1999
  pp. 108)
• In general terms this means that the processing
  power effectively doubles every 3 - 4 years
• though the actual figure is nearer 20 increase
  per year for mainframes and roughly 25 per year
  for PCs.

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Buying A PC

• Analyse your needs for computer purchase
• Choose software that will support your needs.
• Identify hardware that will support your software
• Produce a shortlist and choose your preferred
  platform (PC/Mac) - seek advice
• Obtain quotes and negotiate
• Dont be influenced by bundling
• Pay by credit card - not store finance
• Adhere to standards - look for an upgrade path

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Why Standards?

• Reduce complexity and diversity
• Make systems understandable and manageable
  (interchangeable parts)
• Reduce cost and risk
• As an IS manager how can you enforce standards
  throughout the organisation?
• Turban et al (2000) note that Dell Supplied
  10,000 standard platform PCs to Eastman
  Chemicals, delivering savings of 5.6 M US in
  costs and reducing support staff from 167 to 42

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Thin Clients Disposables

• Thin client machines rely on using a computer
  network
• the network becomes the computer and the client
  becomes a display device with limited processing
  power but a longer effective life.
• Much of the costs of PCs comes about because we
  have to maintain compatibility with earlier
  hardware (serial and parallel ports). Cheaper,
  sealed for life devices are marketed - some for
  as little as 500.

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Purchasing Hardware

• Establish criteria and call for expressions of
  interest (EOI)
• The request for proposal (RFP)
• Evaluating and validating responses
• Negotiating and overseeing the contract for
  supply
• Delay purchasing until the best possible time
• Never assume that batteries are included!
• Offload configuration and installation onto the
  supplier if possible

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Summary

• Standardise on hardware platforms
• Use widely recognised and supported standards
• Beware of state of the art technology it can be
  high risk
• The difference between leading edge and bleeding
  edge is slight