The Risks Digest

The RISKS Digest

Forum on Risks to the Public in Computers and Related Systems

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

Volume 9 Issue 94

Friday 25 May 1990

Contents

o More on Stamford CT Telephone Switch Outage
PGN
o Duplicate RISKS mailings...SOLVED!
Emmett Hogan
o Cross about CRIS (Crime Report information System)
Pete Mellor
o Disk failures after extended shutdown
David Keppel
o The Internet is growing up!
Scott Deerwester
o Are government secrets safer if not classified?
Mary Culnan
o Risks of slandering ... in public forums [re: P.T.U.U.I.]
Tom Blinn
o A320 again
Nancy Leveson
o M1 Air Crash Inquest
Brian Randell
o Tempus Fugit -- Claremont Clock Tower Tick Talk
Brian Randell
o Telephone network synchronization and NavSat
John T. Mulqueen via James Price Salsman via JC%RMC
o National Geographic also wants me to move
Tim Kay
o Re: Irrational and nonvaledictory reasoning
John Chew
o Info on RISKS (comp.risks)

More on Stamford CT Telephone Switch Outage (RISKS-9.93)

"Peter G. Neumann" <neumann@csl.sri.com>
Fri, 25 May 1990 14:37:39 PDT
AT&T announced today that they have resolved most of the cause of last
Thursday's 18-hour local-call switch outage.  Apparently 10,000 subscribers
were being moved from the #1A ESS to the new #5 ESS.  During the cutover there
is apparently a two minute atomic-action interval during which nothing works.
Due to a burp, call storage was lost altogether.  They found procesor problems
that have STILL not been diagnosed.  They also found a cable that had been
incorectly connected last summer, and that remained undetected until the crash.
When the backup failed as well, diagnostics could not be run except by
old-fashioned oscilloscopic probes.  [Source: Brief phone conversation with
Seth Angott of The Advocate in Stamford CT.  Any inaccuracies are mine.]


Duplicate RISKS mailings...SOLVED!

Emmett Hogan <hogan@csl.sri.com>
Fri, 25 May 90 14:25:26 -0700
The nasty bug that was hitting the RISKS Digest mailings has been discovered
and dealt with (hopefully, never to rear its ugly head again).  Apparently, the
problem did not lie with sendmail at all, but instead with a cron job that was
running on our mailhost.  The purpose of this job was to fix a very old bug in
sendmail which would result in messages sitting in the mail queue forever.

The cron job worked like this:

        1) Check to see what sendmail processes are running,
       Keep track of them.
    2) If a sendmail process has been running since the
       last time through, kill it.  It basically assumes
       that a queue should be processed in a certain
       amount of time (back to 6th grade..."you know what
       happens when you assume....")

Well, with the advent of nameservers, it is not abnormal for a message with a
large number of recipients (i.e. RISKS Digest) to take quite a while to run.
And because of the varying response time of the nameservers, a list which
processed quickly one time might take a while longer the next...hence different
RISKS sublists were hit each time.  To add to the problems, this code was
buried in a cron job which needs to be run to clean up the mail queue
directory.

PLEASE NOTE: This does NOT fix the problems on BITNET, where people
are receiving duplicate mailings.  There is a group of people at Penn
State who have dedicated their existance to solving this problem :-).

Jim Duncan (jim@augusta.math.psu.edu) explained what SEEMS to be the BITNET
problem:

 The problem is that there are multiple sites gatewaying certain mailing lists
and newsgroups, and they don't do it in a consistent manner.  Also, some of the
problem is due to the differences in the plethora of news propagation packages
(Bnews, Cnews, Netnews) out there on Usenet.

We're trying to solve the problem by initially setting up a registry for
BITNET<-->LISTSERV<-->Usenet gateways.  We'll make sure there's only one
site gating a certain group, and hopefully cut down on the problem
significantly.  When we get that under control, we're going to attack the
other problems.  But first we want to get a handle on the gateways.

By the way, the group of people looking after this project can be reached at
<news-admin@cs.psu.edu>.  If someone wants to know more, ask'em to send mail
there.

Emmett Hogan              Computer Science Lab, SRI International
UUCP: {ames, decwrl, pyramid, sun}!fernwood!hercules!hogan
USMAIL: BN179, 333 Ravenswood Ave, Menlo Park, CA  94025
ICBM: 37d 27' 14" North, 122d 10' 52" West


Cross about CRIS (Crime Report information System)

Pete Mellor <pm@cs.city.ac.uk>
Fri, 25 May 90 21:31:42 PDT
>From the Guardian Computer section, Thursday, May 24:

Headline: "Police start to get cross about Cris"

"The Met [Metropolitan Police Force] is computerising its system of recording
reported offences, but villains will be happy to hear that the scheme is behind
schedule. Sid Smith reports:

A crime-busting computer network, which revolutionises police methods of
storing records, is so late that the police are claiming compensation from the
system designers [SD-Scicon]. And police staff say that such delays are typical
of government tendering methods.

Cris, the &17 million Crime Report information System, will replace the archaic
written crime books used at London police stations to record reported offences.

[stuff omitted]

Instead of entering crime reports into unmanageable written records, police
staff will type the data into computer terminals at the police station. The
data will then be passed to a DEC MicroVAX minicomputer at the local divisional
headquarters, which in turn will copy it to duplicate database on a multi-node
VAXcluster at the Metropolitan Police's central computer facility."

To summarise: The Met thinks this will be the largest relational database in
Europe. Response times should generally be a few seconds. 2000 terminals in
200 buildings will handle 1 million crime reports a year. The purpose is to
cross-search all other reports for any new crime reported. It should be
particularly useful for "putting additional crimes for a prisoner to take into
consideration".

The general non-criminal public will have access under the Data Protection Act.

The report goes on to say:

"The importance of public access to files was underlined earlier this year by
a case in the Watford area. A clerk operating a computer at a local magistrates
court entered the crime code 216 instead of 261. As a result, several
individuals were accused of unlawful sexual intercourse instead of the correct
alleged offence - using a TV set without a licence."

On the following page of the same issue of the Guardian is another article
headed "The insidious growth of Gigo and how to halt it".

There we read that: "The most common form of clerical error is transposing
digits (writing 1324 instead of 1234). Check-digits prevent transposition
errors on coded information..."

One hopes that the designers of CRIS read the Guardian :-)

Peter Mellor, Centre for Software Reliability, City University, Northampton
Square, London EC1V 0HB


Disk failures after extended shutdown

David Keppel <pardo@cs.washington.edu>
22 May 90 05:22:31 GMT
Recently, a several-hour power failure shut down all of our computers.  Most of
the computers rebooted from this unexpected failure.  Our largest VAX, however,
refused to reboot.  When DEC field service arrived, they were able to reboot
the machine only by replacing several of the hard disks.  The data that had
been written since the last backup was completely lost.

Apparently, there have been problems with some of the RA90 disks.  When they
are shut down and restarted, they function normally.  Apparenly, however, if
they are shut off long enough to cool down, the bearing seals fail and oil is
spewed all over the disks.  This failure has apparently been observed in a
small but significant (a few percent) of the disks.

A point to ponder: The last I heard, DEC had not told its customers.  The aware
customer may be able to avoid extended shutdowns and/or do backups just before
shutdown.  Also, the aware customer may be able to plan an extended shutdown
just before a planned field service call, allowing the user to explore possible
failure in a planned way.


The Internet is growing up!

Scott Deerwester <scott%sage@gargoyle.uchicago.edu>
Fri, 25 May 90 10:45:57 CDT
Consider:

5/8:    Jim Vavrina reads Nick DiGionanni's description of Military
    Viruses in VIRUS-L 3-90.
5/10:   Jim gets a FAX of Rory O'Connor's article, and finds the
    person that Rory interviewd.  Jim writes an article to the
    net, which David Brierly forwards on 5/13 to RISKS.
5/11:   Andy Warinner gives a summary of an SBIR solicitation that is
    probably the source of Nick's description.
5/20:   Rory O'Connor reads Jim's article on the net, and responds in
    RISKS to the charges that Jim made.

All of this happened in the space of a little over a week, all over
the net.  I don't find it remarkable when a bunch of computer types
chat at each other over the net.  But the fact that most of the people
involved in this incident (and I have *no* comment on the incident)
can all chat about it over the net, including a reporter for a San
Jose paper.  Amazing.

Scott Deerwester, Center for Information and Language Studies, University of
Chicago, 1100 E. 57th, CILS Chicago, IL 60637 Phone: 312-702-6948


Are government secrets safer if not classified?

<mculnan@guvax.georgetown.edu>
22 May 90 07:55:00 EDT
In his most recent newsletter, Senator Daniel Patrick Moynihan (D-NY) writes:

"Something called, I'm sorry to say, the Information Security Oversight Office
located in the General Services Administration, has just reported that in 1989
the government created 6,796,501 new secrets.  Half again the number of new
babies.  Is it not likely that the present system of classification actually
calls attention to things we would closely hold?  If an envelope is marked TOP
SECRET -- one of the lower classifications by the way -- does that make a spy's
work easier?

There must be some amateur mathematicians and cryptographers who receive this
newsletter.  Would anyone care to demonstrate that real secrets-- I would judge
there are maybe one hundred new ones every year -- would be safer if *NOT*
classified?  I will insert selected replies in the Congressional Record. (Which
incidentally is a good hiding place for secrets.  Even the Russians are known
to have despaired of deciphering it)."

Any ideas should be sent directly to Senator Daniel Patrick Moynihan, U.S.
Senate, Washington, D.C. 20510.

Mary Culnan, School of Business Administration, Georgetown University


Risks of slandering identifiable individuals/businesses in public forums

"Dr. Tom @MKO, CMG S/W Mktg, DTN 264-4865" <blinn@dr.enet.dec.com>
Tue, 22 May 90 07:16:02 PDT
RISKS DIGEST 9.93 (Monday 21 May 1990) included an announcement of P.T.U.U.I.
from Robert Hardy (a195@mindlink.UUCP).

Since this appears to be a "bulletin board" and presumably allows unrestricted
public access, anyone considering posting the sort of contributions that are
being sought might want to also consider the risks of being taken to court on
civil charges of slander, business defamation, and the like.  Even though the
BBS operator may be able to disclaim responsibility (through a "freedom of the
press" argument, for instance), identifiable contributors probably can not get
the same freedom.  Of course, contributors can "fake" their names so that they
can not be traced (unless it's one *HELL* of a clever BBS, in which case using
one of the 1-900 route-through services would probably fool it), but how much
credence can anyone place in *anonymous* slander?

Clearly, there are RISKS in working for small businesses, and especially in
working for individuals.  Most of those risks can be controlled by checking
references (you *can* ask a prospective employer for references, after all),
by making sure your own rights are spelled out in a contract between you and
your employer, and so forth.  In other words, there are better ways to make
sure your own rights are protected than by participating in organized slander.

>We would like to act as an `Ombudsman' to mediate desputes.

Acting as an "Ombudsman" is very different from acting as a clearinghouse for
unsubstantiated and perhaps inaccurate defamatory statements.

Tom

Dr. Thomas P. Blinn, Marketing Consultant, Application Platforms, U. S.
Channels, Digital Equipment Corporation, Continental Blvd. -- MKO2-2/F10
Merrimack, New Hampshire 03054
Usenet:   ...!decwrl!dr.enet.dec.com!blinn    Phone: (603) 884-4865


A320 again

Nancy Leveson <nancy@safety.ICS.UCI.EDU>
Thu, 24 May 90 02:16:38 -0700
The 21 May 90 issue of Newsweek has an article on the A320.  It gibes with the
rumors I have heard from people in the aircraft industry (although they have
told me about even more suspected control systems problems than are mentioned
in this article).

         A Bumpy Ride for the Airbus A320:
     Northwest's newest fleet comes under scrutiny
        by Annetta Miller with Karen Springen

"It's been one of the more controversial aeronatic introductions since Kitty
Hawk.  And last week the highly automated Airbus A320 jetliner bumped up
against still more turbulence.  Northwest Airlines, the only U.S.  carrier to
operate the planes, acknowledged that it has reported suspected malfunctions of
the aircraft's flight control system to the Federal Aviation Administration.
The reports come on the heels of two overseas crashes involving the $32 million
plane.  While both Northwest and the plane's manufacturer say it is safe to
fly, the crashes and the reports to the FAA raise questions about its
reliability -- and the limits of technology.  `The controversy is always out
there,' says Edwin Arbon of hte Flight Safety Foundation.  `Are we going too
far with automation?'"



M1 Air Crash Inquest

Brian Randell <Brian.Randell@newcastle.ac.uk>
Wed, 23 May 90 16:37:20 BST
Today's UK newspapers carry lengthy accounts of the results of the inquest that
has just been held into the deaths arising from the Kegworth (M1) air crash.
Here, quoted without permission, are two articles from the Independent. About
half of the first article is included, and all the second. (Other articles have
the titles "Decision by pilots to switch off good engine remains a mystery" and
"Training of cabin crew may change".)

Brian Randell

::      "Lessons must be learnt from M1 air crash, inquest told."
::                   - by Stephen Ward
::
::  The coroner at the inquest in to the deaths of 47 people in the M1 air
::  crash yesterday listed eight areas where he believed safety could be
::  improved.
::  .....
::
::  The crash happened after one of the aircraft's engines malfunctioned
::  but the pilots switched off the wrong one.  Mr Tomlinson said he would
::  be writing to the Department of Transport's Air Accident Investigation
::  Branch (AAIB) and to the Civil Aviation Authority regulatory body with
::  a list of areas he though were important.
::
::  -The relationship between the cockpit crew and the cabin crew,
::  particularly in an emergency.  (The cabin staff saw fire from the
::  left-hand engine, but did not tell the pilots.)
::
::  - Urgent provision of external cameras and monitor screens so pilots
::  can see the outside of the aircraft, including the engines.
::
::  - Warning lights on the vibration monitor instruments, as
::  `attention-getters' and to identify which engine was at fault.
::
::  - Red areas on the vibration dials when they approach danger levels,
::  as with other instruments.
::
::  - New or modified types of engines to be tested in flying conditions
::  before approval.  (The CFM-56 engine in the crash had only been
::  bench-tested).
::
::  - Pilot training to emphasise the importance of new instrument
::  systems, particularly where they replace an instrument which has been
::  largely ignored in the past.  (Early vibration monitors were
::  unreliable).
::
::  - Design of instrument panels, and their relationship with other
::  controls.  (The 737-400 had new, electronic dials).
::
::  - The factors in the design of the cabin which meant some passengers
::  survived the impact while others died.
::  .....
::      --------------------------------------------------------
::
::       "High-tech cockpits `may be gap in safety' "
::         - by David Black, Transport Correspondent
::
::  `Glass cockpits' like the one on board the British Midland Boeing 737
::  that crashed at Kegworth, are of a design close to the cutting edge of
::  aviation technology.  The decision to introduce them was a matter of
::  economics.
::
::  Everyone should have been happy - the airline because it was going to
::  cost them less to fly 'glass cockpit' jets, which incorporate six
::  cathode ray tubes in place of the electro-mechanical guages in older
::  airlines; passengers because tickets would be cheaper; and pilots
::  because the new gadget would cut workload.
::
::  However, the recent spate of seemingly inexplicable accidents and
::  incidents involving these new high-tech airliners points to a gap in
::  aviation's safety defences.  In their pursuit of efficiency, the
::  industry may have brought the environment of pilots into the age of
::  information but omitted to teach them how to manage it.
::
::  The Kegworth inquest is over but the official report by the Department
::  of Transport's Air Accidents Investigations Branch has yet to come.
::
::  Although written, it is unlikely to be published before late summer.
::  But it is understood that it is not the flight deck crew, who
::  mistakenly shut down the wrong engine, that come in for most
::  criticism, but the design of the 737' `glass cockpit' and the training
::  that crew receive in operating it.
::
::  The computer systems that run the `glass cockpits' are also subject
::  to question after two crashes of the world's most advanced
::  computerised airliner, the Airbus A320, and other incidents in which
::  the computer overrode the crew's commands and `crashed' the aircraft,
::  despite efforts to prevent it.
::
::  Behind these problems lies the deceptive simplicity of `glass cockpit'
::  operations.  In an old cockpit, there are several hundred guages
::  feeding off many more sensors, the guages maintained with all the
::  skills of a watchmaker.
::
::  However, in a `glass cockpit' there are only the six cathode ray
::  tubes, as in an ordinary television, and if one fails the information
::  displayed on it can be punched up on its neighbour.  Repair is
::  achieved by unplugging the component and plugging in another.
::
::  The system works because all the sensors feed their information into
::  three flight management computers, each policing the the other for
::  mistakes.  They take responsibility for the information the pilot sees
::  on his screen.  The pilot's workload is cut because the computer will
::  assess each problem for him.
::
::  The computers will also identity the nature of the fault and present
::  the pilot with a checklist of action to be taken.
::
::  Herein lies the deception.  While six screens have replaced up to 400
::  instruments, the information passing through those screens is vast.
::  In one column alone on a flight management display, different messages
::  the equivalent of three A4 pages in length can flash up, and each of
::  those can be colour-coded to represent a different status.  The pilot,
::  to understand what his aircraft is doing, must first understand what
::  the computer is doing.
::
::  That flies in the face of basic airmanship and pilots' comments
::  reflect the dilemma.  One said: "With old cockpits the workload was
::  high but you were always aware of what's going on.  Things either
::  worked or they didn't.  With the computer you have to back-track to
::  find the initial error before you can correct "
::
::  Another commented: "With a flight management computer there is almost
::  a sense of disbelief.  You ask "Why's it doing that?" and then you get
::  sucked into an intellectual exercise of trying to work out what is
::  going on."
::
::  "Why is it doing that?" is the most common phrase passing between
::  pilot and co-pilot on a modern jet, according to Dr Roger Green, of
::  the RAF's Institute of Aviation Medicine.  In a lecture to the Royal
::  Aeronautical Society he said: "Modern pilot training methods [and
::  `glass cockpits'] are distancing the pilot from his aircraft and
::  environment."
::
::  When the unexpected happened, the pilot was less likely to be able to
::  deal with the emergency quickly or accurately, he said.
::
::  Pilots feel that the transfer of computer technology from office to
::  cockpit has gone through on the nod without anyone paying attention to
::  the different working environments.  If this quantum leap in aviation
::  technology is to succeed, more attention must be paid to the human
::  factor.
::
::  Captain Kevin Hunt, the pilot in the M1 crash, was very experienced
::  but had flown the 737 type that crashed for only 23 hours.  His
::  co-pilot had only 53 hours on the type.  Each had received only a
::  day's classroom training on its instruments, the inquest was told.
::
::  The AAIB report's likely recommendations on cockpit design and pilot
::  training seem to indicate that they, too, are coming to share the
::  pilot's worries


Tempus Fugit

Brian Randell <Brian.Randell@newcastle.ac.uk>
Fri, 25 May 90 13:08:41 BST
RISKS 9.32 carried a message from me about the master/slave clock system in the
Claremont tower at the University of Newcastle upon Tyne. (The gist of the
message was that the design was totally - indeed unbelievably - inadequate,
through failing to provide *any* means of synchronising the slave clocks from
the master, e.g for fault tolerance purposes, or for summer time changes.)

I thought RISKS readers might be amused by how this 25-year old system has
suddenly come to the end of the line.

Recently workmen were found in the Tower, tiling a patch of wall, on each
level, to make good damage caused by installation and refurbishment of the lift
(elevator) systems. Quite aside from the fact that the result of such
("lavatory") tiling was aesthetically unpleasing, to say the least, we
complained at the lost opportunity.  By this I mean that the tiler was
carefully, and with great difficulty, cutting large circular holes in the
tiles, to allow the slave clocks to be re-installed in the walls!

A colleague edited the ensuing email correspondence within the Computing Lab
about this activity, plus my original RISKS posting, to produce a document to
accompany a request to our Bursar's Office that this work be halted and the
clock system be removed instead.  This request was answered far faster than
past experience with this Office would have led us to expect - indeed almost
immediately after the tiling was complete!

Moreover the answer was much more positive that we expected - the clock system
was to be removed, and the holes in the tiling made good.  In fact this work
started on the very day that the reply arrived. So the offending system is now
no more, though there is a strong possibility that the rather fine looking
master clock will be put on display somewhere in the Computing Laboratory (with
an account of how RISKS helped in its demise). However if anybody wants a large
number of slave clocks, our Bursar's Department might be able to help them!

Brian Randell, Computing Laboratory, University of Newcastle upon Tyne, UK
PHONE = +44 91 222 7923    FAX = +44 91 222 8232


Telephone network synchronization and NavSat

<JC%RMC@ugw.utcs.utoronto.ca>
Wed, 23 May 90 01:26:55 EDT
The following is excerpted from SPACE Digest V11 #419.  The phone companies
seem to have assumed that DoD would not change the operation of their
NavStar satellites.  This sounds to me like another example of using a non-
standard 'feature' and being stung for it later.

  Date: Thu, 17 May 90 18:07:06 -0400 (EDT)
  From: James Price Salsman <js7a+@andrew.cmu.edu>
  Subject: GPS/NAVSTAR news

  >From _Data_Communications_ (ISSN 0363-6399) vol. 19, no. 6, May 1990, p. 56
  (c) 1990 McGraw-Hill Inc

DOD DITHERS DIGITAL DATA

Telephone network synchronization is an unlikely topic for heated
controversy, but that is what the U.S. Department of Defense has
provoked by tampering with the Navstar Global Positioning Satellite
(GPS) system that AT&T plans to use as a network clock.

GPS is a group of 13 satellites now in operation and 27 more to be launched by
1994 [I believe this is in error, as there are to be 27 total satellites in the
constellation --jps], each of which produces and encrypted P code that the
military uses to guide missiles, and another signal, called the
Clear/Acquisition signal, that has been available for commercial uses like
surveying and timing communications networks.

But the DoD has decided that even the C/A signal is too accurate to be
generally available, so it has begun a practice it calls "selective
availability."  That delicious piece of bureaucratese means that the DoD will
introduce random noise on the C/A signal, known in some circles as "dithering,"
to make it difficult or even impossible to use.

Meanwhile, some commercial equipment manufacturers and users, such as land
surveyors, are already relying on the signal and now are angry that the DoD is
changing the rules.  "There is a big controversy about why the government is
doing this," says Jim Jespersen, a staff member of the time and frequency
division of the National Institute of Standards and Technology (Boulder,
Colo.), "especially since the threat from the Russians is not so severe."  [The
"Russians" have a very accurate GPS system of their own, called GLONASS, so
someone is confused here... --jps]

GPS is run by the U.S. Air Force Systems Command's Space Division in Los
Angeles.  The officer in charge of the project, Col. Marty Runkle of the Joint
Program Office, could not be reached for comment.

As for AT&T, George Zampetti, a Bell Laboratories scientist who is in charge of
developing AT&T's synchronization scheme, says that the company plans to use
the C/A signal even if it is dithered.

Zampetti and John Abate, another Bell Labs scientist, say AT&T will use 3B2
computers to filter out the noise to get close to the true signal.  Filtering
will slow down but not eliminate the use of GPS, Abate says.

"We could go a month and still maintain" on error in 100 billion events,
Zampetti says.

The key to the system is Rubidium clocks that actually pass timing to AT&T's
switches and transmission network.  Those Rubidium clocks can maintain network
timing to meet requirements of ANSI and CCITT standards, Zampetti says.  AT&T
would use GPS to calibrate and monitor the rubidium clocks.  -John T. Mulqueen

[The main article (of which that was a sidebar) talks about MCI and Sprint's
use of Loran, atomic clocks, and describes GPS.  The ANSI standard in question
is T1.101, by committee T1X1.3, which describes synchronization for
high-bandwidth long-haul digital transmission. --jps]


National Geographic also wants me to move (RISKS-9.73)

<tim@ggumby.cs.caltech.edu>
Tue, 22 May 90 13:34:08 PDT
I reported earlier that United MileagePlus couldn't get my address straight.
I told them     Timothy L. Kay,     Box 256-80,     Pasadena, CA  91125
and they kept changing my zip code to 91102.  Then I started seeing
this problem with several other companies, all from the eastern half
of the United states.  I have asked them for help in debugging the
problem, and they all point their fingers at the US Postal Service,
but none of them has yet given me a name to talk to.

National Geographic has gratiously sent me every issue by first class mail as
soon as I report that it is late.  The postage comes to about $2.25 per issue.
That is pretty generous of them, considering that my subscription for 12
monthly issues is $21.00.  That is the price they pay if they can't tell their
computer to ignore (erroneous) redirects from the Post Office.

My favorite memorabilia (so far) is a letter from National Geographic that says
that the Post Office has told them that this address is no good, and could I
please inform them of a good one.  Of course, they sent the letter to the "bad"
address.  It reminds me of an IBM PC clone that booted with the following error
message:
                "... missing keyboard; hit F1 to continue."


Re: Irrational and nonvaledictory reasoning

John Chew <john@trigraph.uucp>
Wed, 23 May 90 17:11:10 EDT
In RISKS DIGEST 9.93, "Peter G. Neumann" <neumann@csl.sri.com> quoted a UPI
report that three Florida seniors had obtained GPAs of 4.2857142, and then
suggested "that no one along the way recognized 4 and two sevenths in
disguise."

Well, if *my* GPA were actually 30/7 and a school had salamied me of almost an
entire unit in the last digit of the calculated figure (the correct value of
4.285714 2857142 ... is of course *much* closer to 4.2857143), I'd be posting
now to complain about the risks of grade-point truncation. :-)

                              [A Bit Off More Than You Could Chew?  PGN]

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