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 1 Issue 02

Friday, 28 Aug 1985


o Introduction; three more risk items
Peter Neumann
o Mariner 1 Irony
Nicholas Spies
o RISKS Forum ... [Reaction]
Bob Carter
o RISKS Forum ... [An Air Traffic Control Problem]
Scott Rose
o Risks in AI Diagnostic Aids
Art Smith
o Warning! ... [A Trojan Horse Bites Man]
Don Malpass
Martin Moore
Jim Horning
John McCarthy
John McCarthy
Peter Karp
Dave Parnas
Gary Martins
Tom Parmenter
o The Madison Paper on Computer Unreliability and Nuclear War
Jeff Myers
o Can a Computer Declare War?
Cliff Johnson

Introduction, and more recent risk items

Peter G. Neumann <Neumann@SRI-CSL>
27 Aug 1985 23:32:01-PST

I was away during the previous three weeks, which made it difficult to put out another issue. However, the newspapers were full of excitement relevant to this forum:

I expect that future issues of this RISKS forum will appear at a higher frequency — especially if there is more interaction from our readership. I will certainly try to redistribute appropriate provocative material on a shorter fuse. I hope that we can do more than just recapture and abstract things that appear elsewhere, but that depends on some of you contributing. I will be disappointed (but not surprised) to hear complaints that we present only one side of any particular issue, particularly when no countering positions are available or when none are provoked in response; if you are bothered by only one side being represented, you must help to restore the balance. However, remember that it is often easier to criticize others than to come up with constructive alternatives, and constructive alternatives are at the heart of reducing risks. So, as I said in vol 1 no 1, let us be constructive.

Mariner 1 irony

16 Aug 1985 21:23-EST

My late father (Otto R. Spies) was a research scientist at Burroughs when the Mariner 1 launch failed. He brought home an internal memo that was circulated to admonish all employees to be careful in their work to prevent similar disasters in the future. (I don't recall whether Burroughs was directly involved with Mariner 1 or not.) After explaining that a critical program bombed because a period was substituted for a comma, the memo ended with the phrase

"... no detail is to [sic] small to overlook."

My father would be deeply pleased that people who can fully appreciate this small irony are now working on ways to prevent the misapplication of computers as foible-amplifiers.

Forum on Risks to the Public in Computer Systems [Reaction]

_Bob <Carter@RUTGERS.ARPA>
8 Aug 85 19:10 EDT (Thu)

Thanks for the copy of Vol. I, No. 1. Herewith a brief reaction. This is sent to you directly because I'm not sure whether discussion of the digest is appropriate for inclusion in the digest.

  1. Please mung RISKS so that it does not break standard undigestifying software (in my case, BABYL).

    [BABYL is an EMACS-TECO hack. It seems to be a real bear to use, with lots of pitfalls still. But I'll see what I can do. Alternatively, shorter issues might help. PGN]
  2. I think RISKS is clearly an idea whose time has come, but I'm not entirely sure it has been sufficiently thought through.

    [I should hope not! It is a cooperative venture. I just happen to be trying to moderate it. PGN]
    1. You cast your net altogether too widely, and include some topics that have been discussed extensively on widely-read mailing lists. Star Wars, the Lin paper, the Parnas resignation, and related topics have been constructively discussed on ARMS-D. I have considerable doubt about the utility of replicating this discussion. (The moderators of HUMAN-NETS and POLI-SCI have both adopted the policy of directing SDI debate to that forum. Would it be a good idea to follow that example?

      [To some extent, yes. However, one cannot read ALL of the interesting BBOARDs — there are currently hundreds on the ARPANET alone, many of which have some bearing on RISKS. Also, browsers from other networks are at a huge disadvantage unless they have connections, hours of spare time, money, etc. This is a FORUM ON RISKS, and should properly address that topic. We certainly should not simply reproduce other BBOARDS, but some duplication seems tolerable. (I'll try to keep it at the end of each issue, so you won't have to wade through it.) By the way, I had originally intended to mention ARMS-D in RISKS vol 1 no 1, but did not have time to check it out in detail. For those of you who want to pursue it, next following is the essence of the blurb taken from the Network Information Center, SRI-NIC.ARPA:<NETINFO>INTEREST-GROUPS.TXT. PGN]
      [ ARMS-D@MIT-MC:

      The Arms-Discussion Digest is intended to be a forum for discussion of arms control and weapon system issues. Messages are collected, edited into digests and distributed as the volume of mail dictates (usually twice a week).

      Old digests may be FTP'ed from MIT-MC(no login required). They are archived at BALL; ARMSD ARCn , where n is the issue no.

      All requests to be added to or deleted from this list, problems, questions, etc., should be sent to Arms-D-REQUEST@MIT-MC.

      Moderator: Harold G. Ancell <HGA@MIT-MC> ]

    2. You do not cover the topics which, in my opinion, are going to generate more law-making than anything you do touch on. In particular, the health hazards (if any) of CRT use, and the working conditions (including automated performance testing) of "pink-collar" CRT users are going to be among the most important labor-relations issues of the next few years. Many people think these more imminent risks than those mentioned in the RISKS prospectus.

      [Fine topic! PGN]
  3. I think a digest is an animal that differs considerably from print media, but is no less important. I get the feeling that you consider yourself a country cousin of the ACM publications and of SEN. Wrong! You're not inferior, you are just editing in a different medium and as you put your mind to the task, I hope you come to take them with a larger grain of salt. In particular,

    ! Chinese computer builder electrocuted by his smart computer after he built a newer one. "Jealous Computer Zaps its Creator"! (SEN 10 1)
    was a National Inquirer-style joke. The editor of SEN should not have reprinted it, and you probably should not have included it in a serious list of computer-related failures.

    [The editor of SEN has sometimes been known to indulge in levity. In this case it appears that a Chinese engineer was indeed electrocuted — and that is an interesting case of computer-related disaster. On the other hand, if someone can believe that an AI automatic programming routine can write many million lines of correct code, then he might as well believe that a smart computer system could express jealousy and cause the electrocution! Actually, Bob used "PEN" throughout rather than "SEN", but "Software Engineering Notes" was the only sensible interpretation I could come up with, so I changed it. Do I have a "PEN" pal? PGN]
  4. It seems to me that it is precisely in the area of serious hardware and software failures that RISKS should make its mark. Directing itself to that topic, it fills a spot no existing list touches on directly, and treats a matter that concerns every computer professional who is earning a decent living. Litigation about defective software design and programming malpractice will be the inevitable consequence of risks, and RISKS is the only place to discuss avoiding them. Please consider focussing the list more closely on that subject.

    [Bob, Thanks for your comments. I heartily agree on the importance of the last item. But, I do not intend to generate all of the material for this forum, and can only smile when someone suggests that this forum is not what it should be. I look forward to your help! PGN]

[End of Bob Carter's message and my interspersions.]

RISKS forum [including An Air-Traffic Control Problem]

Scott M. Rose <>
16 Aug 85 21:06:39 PDT (Fri)

I had kind of hoped that somebody would submit something on the recent problem in Aurora Illinois, whereby a computer cable was cut that brought information from RADAR sensors to the regional air traffic control center there. Supposedly, the system was designed to be sufficiently redundant to handle such a failure gracefully, but this turned out not to be the case: there were several close calls as the system went up and down repeatedly. There was information about the problem in the New York Times and the Chicago Tribune, at least... but not in very good detail.

I wonder if the forum is the right format for such a group. The problem is that one may find oneself reluctant to report on such an incident that was widely reported in the popular press, and was current, for fear that a dozen others have done the same. Yet in this case, the apparent result is that NOBODY reported on it, and I think such an event ought not pass without note on this group. I might propose something more like the info-nets group, where postings are automatically forwarded to group members. If problems arose, then the postings could be filtered by the moderator... say, on a daily basis? Just an idea...

-S Rose
[Please don't feel reluctant to ask whether someone has reported an interesting event before you go to any potentially duplicate effort. We'd rather not miss out entirely.]

Risks in AI Diagnostic Aids

Sun, 18 Aug 85 12:23:25 EDT

I would enjoy a discussion on the legal and ethical problems that have come up with the creation of AI diagnostic aids for doctors. Who takes the blame if the advice of a program causes a wrong diagnosis? The doctor (if so, then who would use such a program!?!?), the program's author(s) (if so, then who would write such a program!?!?), the publishers/distributors of the program (if so, then who would market such a program!?!?), .... These nagging questions will have to be answered before anyone is going to make general use of these programs I would be very interested in hearing what other people think about this question. It seems to me that it would be a suitable one for this bboard.

art smith
Following are several items on the Strategic Defense Initiative and related subjects.

WARNING!! [A Trojan Horse Bites Man]

Don Malpass <malpass@ll-sst>
Thu, 15 Aug 85 11:05:48 edt

Today's Wall St. Journal contained the following article. I think it is of enough potential significance that I'll enter the whole thing. In addition to the conclusions it states, it implies something about good backup procedure discipline.

In the hope this may save someone,

Don Malpass
            (8/15/85 Wall St. Journal)
                ARF! ARF!
    Richard Streeter's bytes got bitten by an "Arf Arf," which isn't
a dog but a horse.
    Mr. Streeter, director of development in the engineering department
of CBS Inc. and home-computer buff, was browsing recently through the
offerings of Family Ledger, a computer bulletin board that can be used by
anybody with a computer and a telephone to swap advice, games or programs -
or to make mischief.  Mr. Streeter loaded into his computer a program that
was billed as enhancing his IBM program's graphics; instead it instantly wiped
out the 900 accounting, word processing and game programs he had stored in
his computer over the years.  All that was left was a taunt glowing back
at him from the screen: "Arf! Arf! Got You!"
    This latest form of computer vandalism - dubbed for obvious reasons
a Trojan Horse - is the work of the same kind of anonymous "hackers" who
get their kicks stealing sensitive data from government computers or invading
school computers to change grades.  But instead of stealing, Trojan Horses
just destroy all the data files in the computer.
    Trojan Horse creators are nearly impossible to catch - they usually
provide phony names and addresses with their programs - and the malevolent
programs often slip by bulletin-board operators.  But they are becoming a
real nuisance.  Several variations of the "Arf! Arf!" program have made
the rounds, including one that poses as a "super-directory" that
conveniently places computer files in alphabetical order.
    Operators have begun to take names and addresses of electronic
bulletin-board users so they can check their authenticity.  When a
computer vandal is uncovered, the word is passed to other operators.
Special testing programs also allow them to study the wording of
submitted programs and detect suspicious commands.
    But while Al Stone, the computer consultant who runs Long Island
based Family Ledger, has such a testing program, he says he didn't have time
to screen the "Arf! Arf!" that bit Mr. Streeter.  "Don't attempt to run
something unless you know its pedigree," he says.
    That's good advice, because the computer pranksters are getting more
clever - and nastier.  They are now creating even-more-insidious programs
that gradually eat away existing files as they are used.  Appropriately
enough, these new programs are known as "worms".

            (8/15/85 Wall St. Journal)

Software engineering and SDI

Mon, 19 Aug 85 13:56:21 CDT

[FROM Soft-Eng Digest Fri, 23 Aug 85 Volume 1 : Issue 31]

>Dr. David Parnas has quite accurately pointed out some of the dangers inherent
in the software to be written for the Strategic Defense Initiative.  I must
take exception, however, to the following statement from the Boston Globe
story quoted in Volume 1, Issue 29, of this digest:

"To imagine that Star Wars systems will work perfectly without testing is ridiculous. A realistic test of the Strategic Defense Initiative would require a practice nuclear war. Perfecting it would require a string of such wars." There are currently many systems which cannot be fully tested. One example is the software used in our present defense early warning system. Another example, one with which I am personally familiar, is the Range Safety Command Destruct system at Cape Canaveral Air Force Station. This system provides the commands necessary to destroy errant missiles which may threaten populated areas; I wrote most of the software for the central computer in this system. The system can never be fully tested in the sense implied above, for to do so would involve the intentional destruction of a missile for testing purposes only. On the other hand, it must be reliable: a false negative (failure to destroy a missile which endangers a populated area) could cause the loss of thousands of lives; a false positive (unintentional destruction of, say, a Space Shuttle mission) is equally unthinkable. There are many techniques available to produce fault-tolerant, reliable software, just as there are for hardware; the Range Safety system was designed by some of the best people at NASA, the U. S. Air Force, and several contractors. I do not claim that a failure of this system is "impossible", but the risk of a failure, in my opinion, is acceptably low. "But ANY risk is too great in Star Wars!" I knew someone would say that, and I can agree with this sentiment. The only alternative, then, is not to build it, because any system at all will involve some risk (however small) of failure; and failure will, as Dr. Parnas has pointed out, lead to the Ultimate Disaster. I believe that this is what Dr. Parnas is hoping to accomplish: persuading the authorities that the risk is unacceptable. It won't work. Oh, perhaps it will in the short run; "Star Wars" may not be built now, or ever. But sooner or later, some system will be given life-and-death authority over the entire planet, whether it is a space defense system, a launch-on-warning strategic defense system, or something else. The readers of this digest are the present and future leaders in the field of software engineering. It is our responsibility to refine the techniques now used and to develop new ones so that these systems WILL be reliable. I fear that some first-rate people may avoid working on such systems because they are "impossible"; this will result in second-rate people working on them, which is something we cannot afford. This is NOT a slur at Dr. Parnas. He has performed an invaluable service by bringing the public's attention to the problem. Now it is up to us to solve that problem. I apologize for the length of this message. The above views are strictly my own, and do not represent my employer or any government agency. Martin J. Moore Senior Software Analyst RCA Armament Test Project P. O. Box 1446 Eglin AFB, Florida 32542 ARPAnet: MOOREMJ@EGLIN-VAX.ARPA

Software engineering and SDI

From: horning@decwrl.ARPA (Jim Horning)
Date: 21 Aug 1985 1243-PDT (Wednesday)
To: Neumann@SRI-CSLA
Subject: Trip Report: Computing in Support of Battle Management

[This is a relatively long report, because I haven't been able to come
up with a simple characterization of an interesting and informative day.]


On August 13 I travelled to Marina del Rey to spend a day with the
U.S. Department of Defense Strategic Defense Initiative Organization
Panel on Computing in Support of Battle Management (DoD SDIO PCSBM).

SDI is the "Star Wars" antiballistic missile system; PCSBM is the panel
Dave Parnas resigned from.

I wasn't really sure what to expect. As I told Richard Lau when he
invited me to spend a day with them, I'd read what Parnas wrote, but
hadn't seen the other side.  He replied that the other side hadn't been
written yet. "Come on down and talk to us. The one thing that's certain
is that what we do will have an impact, whether for good or for ill."


The good news is that the panel members are not crazies; they aren't
charlatans; they aren't fools. If a solution to SDI's Battle Management
Software problem can be purchased for five billion dollars (or even
ten), they'll probably find it; if not, they'll eventually recognize
that it can't.

The bad news is that they realize they don't have the expertise to
solve the problem themselves, or even to direct its solution. They
accept Dave Parnas's assessment that the software contemplated in the
"Fletcher Report" cannot be produced by present techniques, and that
AI, Automatic Programming, and Program Verification put together won't
generate a solution. Thus their invitations to people such as myself,
Bob Balzer, and Vic Vyssotsky to come discuss our views of the state
and prospects of software technology.

I think a fair summary of the panel's current position is that they are
not yet convinced that the problem cannot be modified to make it
soluble. ("Suppose we let software concerns drive the system
architecture? After all, it is one of the two key technologies.") They
are trying to decide what must be done to provide the information that
would be needed in the early 1990s to make a decision about deploying a
system in the late 1990s.


Throughout the day's discussions, there were repeated disconnects
between their going-in assumptions and mine. In fairness, they tried to
understand the sources of the differences, to identify their
assumptions, and to get me to identify and justify mine.

* Big budgets: I've never come so close to a trillion-dollar ($10**12)
project before, even in the planning stage. ("The satellite launches
alone will cost upwards of $500 billion, so there's not much point in
scrimping elsewhere.")

- I was unprepared for the intensity of their belief that any technical
problem could be steamrollered with a budget that size.

- They seemed surprised that I believed that progress in software
research is now largely limited by the supply of first-rate people, and
that the short-term effect of injecting vastly more dollars would be to
slow things down by diverting researchers to administer them.

* Big software: They were surprised by my observation that for every
order of magnitude in software size (measured by almost any interesting
metric) a new set of problems seems to dominate.

- This implies that no collection of experiments with million-line
"prototypes" can ensure success in building a ten-million-line system.
I argued that the only prototype from which they would learn much would
be a full-scale, fully-functional one. Such a prototype would also
reveal surprising consequences of the specification.
(The FIFTEENTH LAW OF SYSTEMANTICS: A complex system that works is
invariably found to have evolved from a simple system that works.)

- Only Chuck Seitz and Bijoy Chatterjee seemed to fully appreciate why
software doesn't just "scale up" (doubtless because of their hardware
design experience). It is not a "product" that can be produced at some
rate, but the design of a family of computations; it is the
computations that can be easily scaled.

* Reliability: I had assumed that one of the reasons Battle Management
software would be more difficult than commercial software was its
more stringent reliability requirement. They assume that this is one of
the parameters that can be varied to make the problem easier.


The Panel is still in the process of drafting its report on Battle
Management Systems. Although they take the need to produce such a
system as a given, almost anything else is negotiable. (In particular,
they do not accept the "Fletcher Report" as anything more than a
springboard for discussion, and criticize current work for following it
too slavishly. The work at Rome Air Development Center--which produced
estimates like 24.61 megalines of code, 18.28 gigaflops per weapons
platform--was mentioned contemptuously, while the Army work at Huntsville
was considered beneath contempt.)

The following comments are included merely to indicate the range and
diversity of opinions expressed. They are certainly not official
positions of the panel, and--after being filtered though my
understanding and memory--may not even be what the speaker intended.
Many of the inconsistencies are real; the panel is working to identify
and resolve them.

- The problem may be easier than a banking system, because: each
autonomous unit can be almost stateless; a simple kernel can monitor
the system and reboot whenever a problem is detected; there are fewer
people in the loop; more hardware overcapacity can be included.

- If you lose a state it will take only a few moments to build a new
state. (Tracks that are more than 30 minutes old are not interesting.)

- Certain kinds of reliability aren't needed, because: a real battle
would last only a few minutes; the system would be used at most once;
with enough redundancy it's OK for individual weapons to fail; the
system doesn't have to actually work, just be a credible deterrent; the
system wouldn't control nuclear weapons--unless the Teller "pop up"
scheme is adopted; the lasers won't penetrate the atmosphere, so even
if the system runs amok, the worst it could do would be to intercept some
innocent launch or satellite.

- We could debug the software by putting it in orbit five or ten years
before the weapons are deployed, and observing it. We wouldn't even
have to deploy them until the system was sufficiently reliable. Yes,
but this would not test the important modes of the system.

- Dependence on communication can be minimized by distributing
authority: each platform can act on its own, and treat all
communication as hints.

- With a multi-level fault-tolerance scheme, each platform can monitor
the state of its neighbors, and reboot or download any that seem to be

- In fifteen years we can put 200 gigaflops in orbit in a teacup. Well,
make that a breadbox.

- Space qualification is difficult and slow. Don't count on
microprocessors of more than a few mips in orbit. Well, maybe we could
use fifty of them.

- How much can we speed up computations by adding processors? With
general-purpose processors, probably not much. How much should we rely
on special-purpose space-qualified processors?

- Processor cost is negligible. No, it isn't. Compared to software
costs or total system costs it is. No, it isn't, you are
underestimating the costs of space qualification.

- 14 MeV neutron flux cannot effectively be shielded against and
represents a fundamental limitation on the switching-speed, power
product. Maybe we should put all the computationally intensive
components under a mountain. But that increases the dependence on

- Maybe we could reduce failure rates by putting the software in
read-only memory. No, that makes software maintenance incredibly

- Flaccidware. It's software now, but it can become hardware when

- Is hardware less prone to failure if switched off? Maybe we could
have large parts of the system on standby until the system goes on
alert. Unfortunately, the dominant hardware failure modes continue even
with power off.

- The software structure must accommodate changes in virtually all
component technologies (weapons, sensors, targets, communication,
computer hardware) during and following deployment. But we don't have
much technology for managing rapid massive changes in large systems.

Relation to Critics:

Dave Parnas's criticisms have obviously been a matter of considerable
concern for the panel. Chuck Seitz and Dick Lau both said explicitly
that they wouldn't be satisfied making a recommendation that failed to
address the issues Dave and other critics have raised. Chuck also
distributed copies of "The Star Wars Computer System" by Greg Nelson
and David Redell, commending it to the attention of the panel as
"Finally, some well-written and intelligent criticism."

Richard Lipton had a somewhat different attitude: How can they say that
what we are going to propose is impossible, when even we don't know
yet what we're going to propose? And why don't software researchers
show more imagination? When a few billion dollars are dangled in front
of them, the physicists will promise to improve laser output by nine
decimal orders of magnitude; computer scientists won't even promise one
or two for software production.

The minutes of the August 12 meeting contain the following points:

- Critics represent an unpaid "red team" and serve a useful function in
identifying weak points in the program.

- Critiques should be acknowledged, and areas identified as to how we
can work to overcome these problem areas.

- Throughout our discussions, and in our report we should reflect the
fact that we have accepted a degree of uncertainty as an inherent part
of the strategic defense system.

- How to get the system that is desired? This basic problem goes back
to defining requirements--a difficult task when one is not quite sure
what one wants and what has to be done.


After all of this, what do I think of the prospects for SDI Battle
Management Software? I certainly would not be willing to take on
responsibility for producing it. On the other hand, I cannot say flatly
that no piece of software can be deployed in the 1990s to control a
ballistic missile defense system. It all depends on how much
functionality, coordination, and reliability are demanded of it.

Unfortunately, as with most other computer systems, the dimension in
which the major sacrifice will probably be made is reliability. The
reality of the situation is that reliability is less visible before
deployment than other system parameters and can be lost by default. It
is also probably the hardest to remedy post facto. Of course, with a
system intended to be used "at most once," there may be no one around
to care whether or not it functioned reliably.

Despite these misgivings, I am glad that this panel is taking seriously
its charter to develop the information on which a deployment decision
could responsibly be based.

Jim H.

Software engineering and SDI

[An earlier SU-bboard message that prompted the following sequence of 
replies seemed like total gibberish, so I have omitted it.  PGN]

Date: 13 Aug 85  1521 PDT
From: John McCarthy <JMC@SU-AI.ARPA>
Subject: Forum on Risks to the Public in Computer Systems 
To:   su-bboards@SU-AI.ARPA  
                              [but not To: RISKS...]

I was taking [as?] my model Petr Beckmann's book "The Health Hazards of not
Going Nuclear" in which he contrasts the slight risks of nuclear energy with
the very large number of deaths resulting from conventional energy sources
from, e.g. mining and air pollution.  It seemed to me that your announcement
was similarly one sided in its consideration in risks of on-line systems and
ignoring the possibility of risks from their non-use.  I won't be specific
at present, but if you or anyone else wants to make the claim that there are
no such risks, I'm willing to place a substantial bet.

   [Clearly both inaction and non-use can be risky.  The first two items at
    the beginning of this issue (Vol 1 no 2) — the lobstermen and the Union
    Carbide case — involved inaction.  PGN]

Software engineering and SDI

Date: 14 Aug 85  1635 PDT
From: John McCarthy <JMC@SU-AI.ARPA>
Subject: IJCAI as a forum   
To:   su-bboards@SU-AI.ARPA 

	Like Chris Stuart, I have also contemplated using IJCAI as a forum.
My issue concerns the computer scientists who have claimed, in one case "for
fundamental computer science reasons" that the computer programs required
for the Strategic Defense Initiative (Star Wars) are impossible to write and
verify without having a series of nuclear wars for practice.  Much of the
press (both Science magazine and the New York Times) have assumed (in my
opinion correctly) that these people are speaking, not merely as
individuals, but in the name of computer science itself.  The phrase "for
fundamental computer science reasons" was used by one of the computer
scientist opponents.

	In my opinion these people are claiming an authority they do not
possess.  There is no accepted body of computer science principles that
permits concluding that some particular program that is mathematically
possible cannot be written and debugged.  To put it more strongly, I don't
believe that there is even one published paper purporting to establish
such principles.  However, I am not familiar with the literature on
software engineering.

	I think they have allowed themselves to be tempted into
exaggerating their authority in order to support the anti-SDI cause,
which they support for other reasons.

	I have two opportunities to counter them.  First, I'm giving
a speech in connection with an award I'm receiving.  Since I didn't
have to submit a paper, I was given carte blanche.  Second, I have
been asked by the local arrangements people to hold a press conference.
I ask for advice on whether I should use either of these opportunities.
I can probably even arrange for some journalist to ask my opinion on
the Star Wars debugging issue, so I wouldn't have to raise the issue
myself.  Indeed since my position is increasingly public, I might
be asked anyway.

	To make things clear, I have no position on the feasibility
of SDI, although I hope it can be made to work.  Since even the
physical principles that will be proposed for the SDI system haven't
been determined, it isn't possible to determine what kind of programs
will be required and to assess how hard they will be to write
and verify.  Moreover, it may be possible to develop new techniques
involving both simulation and theorem proving relevant to verifying
such a program.  My sole present point is that no-one can claim
the authority of computer science for asserting that the task
is impossible or impractical.

	There is even potential relevance to AI, since some of the
opponents of SDI, and very likely some of the proponents, have suggested
that AI techniques might be used.

	I look forward to the advice of BBOARD contributors.

Software engineering and SDI

Date: Thu 15 Aug 85 00:17:09-PDT
From: Peter Karp <KARP@SUMEX-AIM.ARPA>
Subject: Verifying SDI software
To: su-bboard@SUMEX-AIM.ARPA

John McCarthy: I argue CPSR's approach is reasonable as follows:

1) I assume you admit that bugs in the SDI software would be very
   bad since this could quite conceivably leave our cities open
   Soviet attack.

2) You concede software verification theory does not permit proof
   of correctness of such complex programs.  I concede this same
   theory does not show such proofs are impossible.

3) The question to responsible computer professionals then becomes:
   From your experience in developing and debugging complex computer
   systems, how likely do you believe it is that currently possible
   efforts could produce error-free software, or even software whose
   reliability is acceptable given the risks in (1) ?

Clearly answering (3) requires subjective judgements, but computer
professionals are among the best people to ask to make such 
judgements given their expertise.  

I think it would be rather amusing if you told the press what you
told bboard: that you "hope they can get it to work".

Software engineering and SDI

Date: 16 Aug 85  2200 PDT
To:   su-bboards@SU-AI.ARPA 
From: John McCarthy <JMC@SU-AI.ARPA>
Subject: sdi 

I thank those who advised me on whether to say something about the
SDI controversy in my lecture or at the press conference.  I don't
presently intend to say anything about it in my lecture.  Mainly
this is because thinking about what to say about a public issue
would interfere with thinking about AI.  I may say something or
distribute a statement at the press conference.

I am not sure I understand the views of those who claim the computer
part of SDI is infeasible.  Namely, do they hope it won't work?  If
so, why?  My reactionary mind thinks up hypotheses like the following.
It's really just partisanship.  They have been against U.S. policy
in many areas including defense, that they automatically oppose any
initiative and then look for arguments.

Software engineering and SDI

Date: Thu, 15 Aug 85 13:01:46 pdt
From: vax-populi!dparnas@nrl-css (Dave Parnas)
Subject: Re:  [John McCarthy <JMC@SU-AI.ARPA>: IJCAI as a forum   ]

McCarthy is making a classic error of criticizing something that 
he has not read.  I have not argued that any program cannot be written 
and debugged.  I argue a much weaker and safer position, that we cannot
know that the program has been debugged.  There are "fundamental computer
science reasons" for that, they have to do with the size of the smallest
representation of the mathematical functions that describe the behaviour
of computer software and our inability to know that the specifications
are correct.  


Date: Thu, 15 Aug 85 13:14:22 pdt
From: vax-populi!dparnas@nrl-css (Dave Parnas)
To: neumann@SRI-CSL.ARPA
Subject: Copy of cover letter to Prof. John McCarthy

Dear Dr. M

	A friend of mine, whose principal weakness is reading the junk mail 
posting on bulletin boards sent me a copy of your posting with regard to 

	It is in general a foolish error to criticize a paper that you have
not read on the basis of press reports of it.

	Nobody has, in fact, claimed that any given program cannot be
written and "debugged" (whatever that means).  The claim is much weaker,
that we cannot know with confidence that the program does meet its
specification and that the specification is the right one.  There is both
theoretical (in the form of arguments about the minimal representation of
non-continuous functions) and empirical evidence to support that claim.  The
fact that you do not read the literature on software engineering does not
give you the authority to say that there are no papers supporting such a

	As I would hate to see anyone, whether he be computer scientist or AI
specialist, argue on the basis of ignorance, I am enclosing ...

Software engineering and SDI

Date: Thu 15 Aug 85 18:50:46-PDT
From: Gary Martins <GARY@SRI-CSLA.ARPA>
Subject: Speaking Out On SDI
To: jmc@SU-AI.ARPA

Dear Dr. McC -

In response to your BB announcement:

1.  Given that IJCAI is by and large a forum for hucksters and crackpots of
various types, it is probably a poor choice of venue for the delivery of
thoughts which you'd like taken seriously by serious folks.

2. Ditto, for tying your pro-SDI arguments in with "AI"; it can only lower
the general credibility of what you have to say.

3.  You are certainly right that no-one can now prove that the creation of
effective SDI software is mathematically impossible, and that part of your
argument is beyond reproach, even if rather trivial.  However, you then
slip into the use of the word "impractical", which is a very different
thing, with entirely different epistemological status.  On this point,
you may well be entirely wrong — it is an empirical matter, of course.

I take no personal stand on the desirability or otherwise of SDI, but
as a citizen I have a vested interest in seeing some discussions of
the subject that are not too heavily tainted by personal bias and
special pleading.

Gary R. Martins
Intelligent Software Inc.


       International Conference on Software Engineering
              28-30 August 1985, London UK
         Feasibility of Software for Strategic Defense
                    Panel Discussion
             30 August 1985, 1:30 - 3:00 PM

        Frederick P. Brooks III, University of North Carolina
        David Parnas, University of Victoria
           Moderator: Manny Lehman, Imperial College

This panel will discuss the feasibility of building the software for the
Strategic Defense System ('Star Wars') so that that software could be
adequately trusted to satisfy all of the critical performance goals.  The
panel will focus strictly on the software engineering problems in building
strategic defense systems, considering such issues as the reliability of the
software and the manageability of the development.

    [This should be a very exciting discussion.  Fred has extensive hardware,
     software, and management experience from his IBM OS years.  David's
     8 position papers have been widely discussed — and will appear in the
     September American Scientist.  We hope to be able to report on this
     panel later (or read about it in ARMS-D???).   Perhaps some of you
     will be there and contribute your impressions.  PGN]


Date: Mon, 15 Jul 85 11:05 EDT
From: Tom Parmenter 

From an article in Technology Review by Herbert Lin on the difficulty
(impossibility) of developing software for the Star Wars (Strategic
Defense Initiative) system:

  Are there alternatives to conventional software development?  Some defense
  planners think so.  Major Simon Worden of the SDI office has said that

    "A human programmer can't do this.  We're going to be developing new
     artificial intelligence systems to write the software.  Of course, 
     you have to debug any program.  That would have to be AI too."


Date: Wed, 14 Aug 85 18:08:57 cdt
From: uwmacc! (Latitudinarian Lobster)
Message-Id: <8508142308.AA12046@maccunix.UUCP>
Subject: CPSR-Madison paper for an issue of risks?

The following may be reproduced in any form, as long as the text and credits
remain unmodified.  It is a paper especially suited to those who don't already
know a lot about computing.  Please mail comments or corrections to:

Jeff Myers                              [Something was lost here...]
University of Wisconsin-Madison		reflect the views of any other
Madison Academic Computing Center	person or group at UW-Madison.
1210 West Dayton Street
Madison, WI  53706
ARPA: uwmacc!myers@wisc-rsch.ARPA
UUCP: ..!{harvard,ucbvax,allegra,heurikon,ihnp4,seismo}!uwvax!uwmacc!myers



     Larry Travis, Ph.D., Professor of Computer Sciences, UW-Madison 
	      Daniel Stock, M.S., Computer Sciences, UW-Madison
	     Michael Scott, Ph.D., Computer Sciences, UW-Madison
	    Jeffrey D. Myers, M.S., Computer Sciences, UW-Madison
	      James Greuel, M.S., Computer Sciences, UW-Madison
James Goodman, Ph.D., Assistant Professor of Computer Sciences, UW-Madison
     Robin Cooper, Ph.D., Associate Professor of Linguistics, UW-Madison
	     Greg Brewster, M.S., Computer Sciences, UW-Madison

                               Madison Chapter
               Computer Professionals for Social Responsibility
                                  June 1984

           Originally prepared for a workshop at a symposium on the
                     Medical Consequences of Nuclear War
                         Madison, WI, 15 October 1983

  [The paper is much too long to include in this forum, but can be 
  obtained from Jeff Myers at the above net addresses, or FTPed from
  RISKS@SRI-CSL:<RISKS>MADISON.PAPER.  The section headings are as follows:

    1.  Computer Use in the Military Today, James Greuel, Greg Brewster
    2.  Causes of Unreliability, Daniel Stock, Michael Scott
    3.  Artificial Intelligence and the Military, Robin Cooper
    4.  Implications, Larry Travis, James Goodman



Date: Wed, 21 Aug 85 17:46:55 PDT
From: Clifford Johnson <GA.CJJ@Forsythe>
Subject:  @=  Can a computer declare war?

****************** CAN A COMPUTER DECLARE WAR?

Below is the transcript of a court hearing in which it is was argued by the
Plaintiff that nuclear launch on warning capability (LOWC, pronounced
lou-see) unconstitutionally delegates Congress's mandated power to declare

The Plaintiff is a Londoner and computer professional motivated to act by
the deployment of Cruise missiles in his hometown.  With the advice and
endorsement of Computer Professionals for Social Responsibility, on February
29, 1984, he filed a complaint in propria persona against Secretary of
Defense Caspar Weinberger seeking a declaration that peacetime LOWC is
unconstitutional.  The first count is presented in full below; a second
count alleges a violation of Article 2, Part 3 of the United Nations Charter
which binds the United States to settle peacetime disputes "in such a manner
that international peace and security, and justice, are not endangered":

1.  JURISDICTION:  The first count arises under the Constitution of the
United States at Article I, Section 8, Clause 11, which provides that "The
Congress shall have Power ... To declare War"; and at Article II, Section 2,
Clause 1, which provides that "The President shall be Commander in Chief" of
the Armed Forces.

2.  Herein, "launch-on-warning-capability" is defined to be any set of
procedures whereby the retaliatory launching of non-recoverable nuclear
missiles may occur both in response to an electronically generated warning
of attacking missiles and prior to the conclusively confirmed commencement
of actual hostilities with any State presumed responsible for said attack.

3.  The peacetime implementation of launch-on-warning-capability is now
presumed constitutional, and its execution by Defendant and Defendant's
appointed successors is openly threatened and certainly possible.

4.  Launch-on-warning-capability is now subject to a response time so short
as to preclude the intercession of competent judgment by the President or by
his agents.

5.  The essentially autonomous character of launch-on-warning-capability
gives rise to a substantial probability of accidental nuclear war due to
computer-related error.

6.  Said probability substantially surrenders both the power of Congress to
declare war and the ability of the President to command the Armed Forces,
and launch-on-warning-capability is therefore doubly repugnant to the

7.  The life and property of Plaintiff are gravely jeopardized by the threat
of implementation of launch-on-warning-capability.

WHEREFORE, Plaintiff prays this court declare peacetime
launch-on-warning-capability unconstitutional.


[in the original message, and is too lengthy to include here.  I presume you
will find it in ARMS-D — see my interpolation into the note from Bob Carter
above.  Otherwise, you can FTP it from SRI-CSL:<RISKS>JOHNSON.HEARING.  PGN]


Please report problems with the web pages to the maintainer