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Can We Trust Our Software?
| 1 |
The
complex computerized financial networks that transfer trillions of dollars
from coast to coast daily are consistently vulnerable to error. Sometimes just
money is at stake: in 1985 a single software malfunction forced the Bank of New
York to borrow $24 billion to cover its accounts temporarily; the cost was $5
million in extra interest. One programming error in Washington allowed ATM cardholders
to make unlimited cash withdrawals regardless of their account balance. Other
times, it's lives. At least one programming mistake has been fatal; in 1986 a
Canadian cancer-therapy machine killed two patients when a software error administered
damaging doses of radiation. |
| 2 |
A large software
program can be tested only by actually trying every conceivable combination
of challenges to see whether it fails. But when programs get very large,
says John Shen, a computer researcher at Carnegie-Mellon University, "it
could take tens, if not hundreds, of years to go through the combinations." The
national air-traffic control system, which ensures the safety of all
commercial aircraft, will be massively retooled this decade, and the
Federal Aviation Administration is still determining just how to certify
that the system works under all conditions. It may not be able to: "The
sky," says FAA resource specialist Mike DeWalt, "is home to an infinite
number of aircraft velocities and positions." |
| 3 |
What's flying around
up there is already loaded with software. In the latest 747, for example,
everything from the navigation system to the toilet is controlled
by computers. The next generation of fly-by-wire aircraft, in which computers
replace traditional mechanical control systems, will be even more software dependent.
Humans will still handle the controls, but their commands will be executed by
complex webs of software. |
| 4 |
The demands on
some programs are so complex that sometimes the writers simply can't
get them right. A Government Accounting Office report in 1988 cited a
satellite-tracking
software program that is $250 million over budget and seven years behind schedule.
At last count, the attempt to upgrade the Defense Department record-keeping computers
was already $1 billion over budget--and congressional analysts have suggested
that the system is so faulty that it is probably impossible to determine the
actual cost overrun. The software for a radar-jamming system was also $1 billion
over budget and four years behind schedule. All of these efforts pale beside
the software that would be needed for the Strategic Defense Initiative, or Star
Wars; critics charge that it could never work reliably.
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| 5 |
Who writes these
programs? Anyone who can sell one. Engineers who design bridges or high-rise
buildings, whose collapse could cost lives, are licensed
and regulated. But thus far, there are no similar requirements for programmers
in the United States. The same programmer who creates a video game for an arcade
can also write the software for a hospital cardiac monitor. The skills are not
necessarily transferable. A Seattle computer instructor remembers one ex-student
who was commissioned to write a program for the cockpit of a jet fighter, only
he didn't know how to fly. |
| 6 |
Programmers themselves
are increasingly concerned about potential liability. A California-based
group called Computer Professionals for Social Responsibility (CPSR)
now has 3,000 members in 21 chapters. At a national meeting of computer
experts last fall, a panel on social ethics and safety drew an audience
of 1,000. But software writers--perhaps the ultimate American garage
entrepreneurs--are likely to resist any official efforts to regulate
their profession. "If there was a law that said you couldn't write software
without a license," says Michael Odala, president of the Software Entrepreneurs
Forum, "most of our members would go find other work." (Rogers, Michael
and David L. Gonzalez, "Can We Trust Our Software?" Newsweek 29 Jan.
1990: 70, 71, 73) |
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