Perspectives on Software

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Perspectives on Software
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Overview
To frame our discussion, consider

• What is the nature of the software industry?
• What is the state of the software industry?
• What influences the industry?

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Outline

• History Lesson
• What is Software?
• Software Industry
• System Costs
• For the Record
• Industry Data
• The Software Crisis

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History (1)

• "I think there is a world market for maybe five
  computers."
• --Thomas Watson, chairman of IBM, 1943
• "I have traveled the length and breadth of this
  country and talked with the best people, and I
  can assure you that data processing is a fad that
  won't last out the year."
• --Editor, Prentice Hall, 1957
• "There is no reason anyone would want a computer
  in their home."
• --Ken Olson, president Digital Equipment Corp.,
  1977

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What is Software?

• Programs and the associated documentation
  required to develop, operate, and maintain
  the program.

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The Essence of Software
From Brooks No Silver Bullet
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State of Software Industry?

• Industry Segments
• In-house Software
• Business Sector Software
• Government Contracting
• PC Software

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Software Development
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For the Record! (1)

• In 1987, California's Department of Motor
  Vehicles decided to make its customers' lives
  easier by merging the state's driver and vehicle
  registration systems. It had hoped to unveil the
  one-stop renewal kiosks last year (1993). The DMV
  saw the projected cost explode to 6.5 times the
  expected price and the delivery date recede
  to1998. The agency pulled the plug after seven
  years and a 44.3 million investment. (SA, p. 89)

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For the Record! (2)

• During the 1991 Gulf War, a Scud missile
  penetrated the Patriot anti-missile shield and
  struck a barracks near Dhahran, Saudi Arabia. In
  all 28 Americans were killed, and 98 wounded. The
  software for the Patriot missile contained a
  cumulative timing fault. Israeli forces detected
  the timing problem after only 8 hours and
  reported the defect to the company. The new
  software arrived the day after the
  tragedy.(Schach, p. 4)

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For the Record! (3)

• In 1986, two cancer patients at the East Texas
  Cancer Center in Tyler received fatal radiation
  overdoses from the Therac-25. (Byte, p. 50)

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For the Record! (4)

• In the summer of 1991, telephone outages
  occurred in local systems in California and along
  the Eastern seaboard. The breakdowns were all the
  fault of an error in signaling software. DSC
  Communications introduced a bug when it changed
  three lines of code in the several million-line
  program. No one thought it necessary to re-test
  the program with the modifications. (Byte, p. 50)

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For the Record! (5)

• Today the FAA still uses the air-traffic-control
  software from the 1970s. It runs on a vacuum-tube
  IBM9020e. This system contributed almost a dozen
  failures this past year. The FAA has been working
  to replace the antiquated system. The FAA has
  been paying Loral (was IBM Federal Systems)
  700-900 per line for the new software to run on
  hundreds of computers and embedded in new and
  sophisticated hardware which must respond around
  the clock to unpredictable real-time events. The
  FAA decided in June 1994 to can two of the four
  parts losing 144 million. The fourth part, new
  workstation software for air-traffic controllers,
  has cost 1.4billion, and is currently under the
  scrutiny of researchers to see if it can be
  saved.

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Industry Data (1)

• GAO Study

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Industry Data (2)

• A more recent study by the Standish Group in
  1995 of 175,000 software projects
• 16 successful
• 53 challenged
• 31 failed

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Influencing Development

• Personal Computing
• Time to Market
• Networking
• Economics
• User Interfaces
• Ubiquitous computing
• Complex Systems

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Example

• Denver International Airport
• A baggage handling system using a system of
  conveyors and carts which would deliver
  individual bags to specified destinations.

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Details

• over 17 miles of track
• 5.5 miles of conveyors
• 4000 carts
• 2700 photo cells
• 59 bar code readers
• 311 radio frequency readers
• more than 150 computers

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Problems

• 1. Hardware advances continues faster than our
  ability to build software to use it.
• 2. Demand outpaces production of software.
• 3. Increasing dependence on software by all
  segments of society.
• 4. Production of software of questionable
  quality.
• 5. Poor maintainability of existing software.
• 6. Productivity Paradox

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Software Crisis (or Chronic Affliction)

• software delivered behind schedule
• software costs exceeds estimates
• software unreliable
• software difficult to maintain
• software performs poorly