Information Technology Reference
In-Depth Information
the computer was the weakest link and a computer error led to the failure of the entire
system. The failure may have been due to a data entry or data retrieval error, poor design,
or inadequate testing. Through a variety of examples, you will gain a greater appreciation
for the complexity of building a reliable computerized system.
We also take a look at computer simulations, which are playing an increasingly
important role in modern science and engineering. We survey some of the uses to which
these simulations are put and describe how those who develop simulations can validate
the underlying models.
Software engineering arose out of the difficulties organizations encountered when
they began constructing large software systems. Software engineering refers to the use
of processes and tools that allow programs to be created in a more structured manner.
We describe the software development process and provide evidence that more software
projects are being completed on time and on budget.
At the end of the chapter, we take a look at software warranties. Software manu-
facturers typically disclaim any liability for lost profits or other consequential damages
resulting from the use of their products. We discuss how much responsibility software
manufacturers ought to take for the quality of their products. Some say software should
be held to the same standards as other products, while others say we ought to have a
different set of expectations when it comes to the reliability of the software we purchase.
Sometimes computerized systems fail because the wrong data have been entered into
them or because people incorrectly interpret the data they retrieve. In this section, we
give several examples of wrong actions being taken due to errors in data entry or data
retrieval.
In the November 2000 general election, Florida disqualified thousands of voters because
preelection screening identified them as felons. The records in the computer database,
however, were incorrect; the voters had been charged with misdemeanors. Nevertheless,
they were forbidden from voting. This error may have affected the outcome of the
presidential election [1].
As we saw in Chapter 6, the databases of the National Crime Information Center (NCIC)
contain a total of about 40 million records related to stolen automobiles, missing per-
sons, wanted persons, suspected terrorists, and much more. There have been numerous
stories of police making false arrests based on information they retrieved from the NCIC.
Here are three.
Sheila Jackson Stossier, an airline flight attendant, was arrested at the New Orleans
airport by police who confused her with Shirley Jackson, who was wanted in Texas. She
spent one night in jail and was detained for five days [2].
