Deck 8: Computer Reliability

Question 1

Which of these problems was not encountered by BAE as it tried to install an automated baggage handling system at Denver International Airport?

A) The system misrouted luggage carts.
B) The bar code printers didn't print tags clearly enough to be read by the scanners.
C) Workers painted over electric eyes installed in the underground tunnels.
D) The automated baggage handlers shredded some of the luggage.
E) The system encountered all of these problems and more.

Answer 1

E

Question 2

The process of determining if a model is an accurate representation of the real system is called

A) the null hypothesis.
B) software engineering.
C) synthesis.
D) validation.
E) verification.

Answer 2

D

Question 3

Computers that process data from sensors as events occur are called

A) distributed computers.
B) event-driven simulations.
C) pseudo-sensory systems.
D) real-time systems.
E) time-activated systems.

Answer 3

D

Question 4

By making the PDP 11 minicomputer an integral part of the Therac-25, AECL was able to

A) reduce costs by replacing hardware safety features with software safety features.
B) increase the stock price of its subsidiary Digital Equipment Corporation.
C) shrink the size of the machine considerably.
D) eliminate the need for lead shielding.
E) All of the above

Question 5

The Patriot missile system

A) was designed to shoot down airplanes.
B) failed to shoot down a Scud missile that killed 28 U.S. soldiers in the Gulf War.
C) failed because it had been left running too long.
D) failed because of a computer error.
E) All of the above

Question 6

The Ariane 5 satellite launch vehicle failed because

A) a faulty on-board computer caused the other computers in the network to crash repeatedly.
B) a bad sensor fed faulty information into the flight control computer, causing it to fail.
C) the rocket's on-board computer sent back faulty information to ground control, causing the human controllers to destroy the rocket.
D) code that worked correctly on the Ariane 4 failed on the Ariane 5.
E) a software failure caused the rocket to self-destruct when in actuality the rocket's flight was going perfectly.

Question 7

A computer used as a component of a larger system is called

A) an embedded system.
B) a mainframe computer.
C) a network.
D) an operating system.
E) a personal computer .

Question 8

The discipline focused on the production of software, as well as the development of tools, methodologies, and theories supporting software production, is most accurately called

A) artificial intelligence.
B) computer engineering.
C) computer science.
D) software simulation.
E) software engineering.

Question 9

Which of these statements about the National Crime Information Center NCIC) is true?

A) The NCIC databases contain about 40 million records.
B) Improper use of the NCIC has led to about 1 million false arrests.
C) Local law enforcement agencies enter 99 percent of the information that is in the NCIC databases.
D) The Department of Homeland Security is in charge of the NCIC.
E) All of these statements are true.

Question 10

Some computer experts have spoken out against the conversion to touch-screen voting machines because

A) there is no evidence that there have been any problems with punched card systems.
B) they are made in China, which does not even hold elections.
C) a power failure could make it impossible for people to vote.
D) they do not have a paper audit trail.
E) All of the above

Question 11

Computer simulations can

A) accurately predict the weather a month in advance.
B) save automobile manufacturers time and money as they develop new cars.
C) prove our planet is overpopulated.
D) All of the above
E) None of the above

Question 12

The AT&T long-distance network did not collapse entirely on January 15, 1990, because

A) the U.S. Secret Service arrested the culprits before they could do any further damage.
B) AT&T technicians rapidly fixed the software bug in the routing switches.
C) MCI loaned some equipment to AT&T.
D) the faulty computers shut themselves off before they could do any further damage.
E) not all the routing switches had been converted to the latest software.

Question 13

Mizuho Securities lost $225 million when

A) hackers broke into its trading system and raided the accounts of 10,000 of its most important customers.
B) a bug in its billing system caused it to send out improper invoices to 10,000 of its most important customers.
C) a bug in its currency trading system caused it to sell yen and purchase dollars when it should have purchased yen and sold dollars.
D) it tried unsuccessfully to automate the Tokyo Stock Exchange.
E) one of its employees mistyped a sell order, and a bug in the Tokyo Stock Exchange trading program made it impossible to cancel the order.

Question 14

Which mistake was not made by AECL, the manufacturer of the Therac-25?

A) It did not include software or hardware devices to detect and report overdoses.
B) It did not tell other hospitals about possible overdose incidents.
C) It reused code without proper testing.
D) It continued to sell the Therac-25 after the FDA declared it to be defective.
E) AECL made all of these mistakes, and more.

Question 15

The Mars Climate Orbiter crashed on the surface of Mars because

A) one program output thrust in terms of foot-pounds, and another program expected thrust to be expressed in terms of newtons.
B) the probe lost contact with the Jet Propulsion Laboratory when it entered the Martian atmosphere.
C) a bug in the computer program caused the vehicle to consume too much fuel on the way to Mars, leaving an inadequate supply for landing.
D) the extreme cold of deep space caused the computer to crash.
E) before programmers went on strike at subcontractor Lockheed Martin, one of them sabotaged the flight control software.