The RISKS Digest
Volume 9 Issue 32

Monday, 16th October 1989

Forum on Risks to the Public in Computers and Related Systems

ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

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o Missed zero blamed for aircrash
Dave Horsfall
o Software reliance/software problems and the Stealth
Marc Rotenberg
o Coping with the unexpected - Friday's stock plunge
Steve Bellovin
o Re: latest stock market crash
Olivier Crepin-Leblond
o Atlantis launch delay
o Keeping up with the [Indian(a)] Joneses in elections
o Friendly advice... [Datacrime]
David Gursky
o Re: Synchronizing Clocks
Brian Randell
o Info on RISKS (comp.risks)

Missed zero blamed for aircrash

Dave Horsfall <>
Tue, 10 Oct 89 14:52:26 est
Taken from "Computing Australia", 9th October:

``Missing zero blamed for aircrash

  Brazilian crash investigators have concluded that a data input error
  caused the Varig Boeing 737 disaster that killed 12 people last month.
  Pilot Cezar Augusto saved the lives of 54 passengers by ditching his
  aircraft in the Amazon jungle tree tops after running out of fuel.

  An investigating team from Rio de Janeiro believe Captain Augusto
  miskeyed his computer-controlled flightpath on take-off, omitting the
  first zero from his true course of "0270" when en route to Mexico.
  The computer navigation system directed the aircraft south instead of
  north without the crew realising until it was too late.

  The findings have been slammed by the Brazilian Airline Pilots'
  Association which says the true fault lay in the computer.  A spokesman
  for the association said it had evidence that a flight course computer
  print-out had detailed the wrong course.  The association is calling
  for a re-examination of Rio de Janeiro Airport's flightpath-mapping
  system to check on its safety.''

Dave Horsfall (VK2KFU),  Alcatel STC Australia,,  ...munnari!!dave

Software reliance/software problems and the Stealth

Tue, 10 Oct 89 17:23:33 -0700
The Washington Post has run an extraordinary three-part series on the
development of the Stealth bomber and the subsequent political turmoil as the
project faces increasing public scrutiny and Congressional skepticism.  The
article was written by Rick Atkinson and appears in the 10/8,10/9, and 10/10
issues of the Post.

These two paragraphs are from today's article:

. . .

"Because of the unique, three dimensional computer design system, Northrop felt
confident enough to skip the usual step of building master tools for a bomber
prototype; instead, AV 1 [Air Vehicle 1, the first B-2 off the production line]
would be a full production plane built with the same 'hard tooling' used on the
rest of the fleet.  Boeing and Northrop tested internal aircraft systems, such
as fuel and hydraulics, on huge 'Iron Birds' that resembled full-sized bombers
with their skins peeled away.  Beginning in 1985, navigation and avionics
equipment was tested in the air of NKC-135 aircraft flying out of Edwards Air
Force Base in the Mojave Desert.

"Northrop believed that it could reduce the number of construction man-hours
from 3.5 million on the first bomber to 1 million on the 11th.  New aircraft
often are plagued with production gremlins; those hiding in AV 1 caused another
six months of delay.  A computer software miscalculation meant that electrical
wiring had to be done over because the first set of wires was cut too short,
according to a former Northrop executive; a pressurized line blew out an took
two weeks to fix because it lay in an inaccessible cranny of the plane." ...

Coping with the unexpected - Friday's stock plunge <>
Sat, 14 Oct 89 18:40:32 EDT
The AP wire service provides financial page tables for many newspapers.
As part of the process, they filter out trades that are more than 3%
off of the current price.  That didn't work on Friday, when the market
plunged; they were forced to adjust their filters to accept 50% differences.
The data was manually filtered before the weekend editions to eliminate
trades that were ``clearly reported incorrectly''.

        --Steve Bellovin

RE: latest stock market crash

Olivier Crepin-Leblond <>
Mon, 16 OCT 89 14:49:24 GMT
Could the current stock market crash have been initially triggered by
a time-bomb type of virus, set to Friday the 13th ?

Olivier Crepin-Leblond, Computer Systems & Electronics,
Electrical & Electronic Eng., King's College London, UK.

Atlantis launch delay

Peter G. Neumann <>
Mon, 16 Oct 1989 16:21:36 PDT
One of the shuttle Atlantis' engine computers was replaced (on Friday the 13th)
and the new one (230 pounds and $6M — or about $25,000 per pound) installed
and checked out the next day.  The launch is now scheduled for 17 October, a
five-day delay.  (A Federal appeals court may consider the challenge to last
week's ruling that the launch can go on despite the risk of plutonium
contamination in the case of an accident, the subject of the earlier case.)

Keeping up with the [Indian(a)] Joneses in elections

Peter G. Neumann <>
Mon, 16 Oct 1989 16:15:39 PDT
Indian computers and Japanese software are about to be used in the first
computerized voting in India.  The opposition party leaders launched a protest,
being concerned about how easily the party in power could manipulate the
elections.  They cited Ronnie Dugger's New Yorker article (7 Oct 1988) noted in
RISKS-7.70 and 78, and displayed a list of some of the ways in which elections
could be rigged electronically.  [Source: NY Times, 15 Oct 1989, page 5.
                              Also noted by henry@garp.MIT.EDU (Henry Mensch).]

Friendly advice... [Datacrime]

David Gursky <>
Sat, 14 Oct 89 14:13:19 EDT
Once again, the voices of Light and Reason have triumphed over those of the
Press.  It seems that speculation of large amounts of data loss due to the
Datacrime virus has been unfounded.

That being said, if you are not in the habit of backing up your computer's
hard disk periodically, this would be a good time to start!  Had Datacrime been
widespread, and you had lost your system's hard disk's contents, where would
you have recovered the information from?

Backups cannot *prevent* malicious software from destroying or corrupting data
stored on your computer's hard disk, but backups are *crucial* to recovering
the data lost to such an attack!  There is an undeniable risk in believing that
your computer is safe from malicious software simply because you practice safe
computing.  Our defenses are only as good as the problems we have seen.  If
tomorrow a vandal writes a new application to attack a computer system in a
novel fashion, or a system that has not been subjected to many attacks, your
data is as vulnerable as if you used no or minimal protection.

I am not trying to be an alarmist here, but the best strategy to safeguarding
your data is a diversified one, and backups are a conerstone to any strategy.

And besides.  Halloween is just over two weeks away.

Re: Synchronizing Clocks

Brian Randell <>
Fri, 6 Oct 89 19:17:28 BST
In RISKS 9.28 Earl Boebert suggested that a UK subscriber to RISKS might care
to investigate whether the Synchronome Co. of Wembley, Middlesex, still
existed.  I have - to the extent of confirming that no company with the name
and address he gave is now listed in the telephone directory.

I was motivated to investigate because of the problems we have with a
master/slave clock system that is installed in building in which my office is
located - though on checking I find that this identifies itself as having been
made by "Gents of Leicester". The Gents system is in fact an appalling example
of a good idea gone wrong. It was selected and installed by the University, I
would guess about 25 years ago, with the aim of assisting avoidance of
synchronisation errors in lecture start/stop times. Unfortunately, it now has
exactly the opposite effect!

The problem is that individual slave clocks occasionally fail to receive, or
react to, pulses from the master, and there is NO means of synchronising the
slave clocks from the master. So, over a period of months, the various slave
clocks gradually get further and further behind the master clock, and only get
re-synchronised when a technician is sent to correct each of them manually - a
job that in a building this size takes many hours if not days, and so is
performed only rarely, when many of the slave clocks are hopelessly slow.

The solution we have adopted in the Computing Laboratory has involved a
unilateral declaration of independence from the central maintenance services.
This is the replacement of those slave clocks which matter to us by ordinary
quartz crystal-controlled wall clocks. These are quite cheap, far more
dependable individually, and subject only to common mode failures which are
likely to cause situations in which the clocks' accuracy is irrelevant, e.g.
collapse of the whole building.

Brian Randell, Computing Laboratory, University of Newcastle upon Tyne UUCP=..!ukc!!Brian.Randell

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