@MIT-MC.ARPA:ARMS-D-Request%MIT-MC.ARPA@MIT-XX.ARPA (10/30/85)
From: Moderator <ARMS-D-Request%MIT-MC.ARPA@MIT-XX.ARPA>
Arms-Discussion Digest Tuesday, October 29, 1985 9:33AM
Volume 5, Issue 8
Today's Topics:
SDI Debate
Falklands Game
Historical A-Bombs and a "what-if"
Are SLBMs safe?
Test Ban
Re: Build Your Own Bomb
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Date: Mon, 28 Oct 85 10:58 EST
From: Mills@CISL-SERVICE-MULTICS.ARPA
Subject: SDI Debate
This is a summary of my impressions of the panel discussion/debate
entitile "Star Wars: Can the Computing Requirements be Met?" This
took place on Monday October 21 at MIT. The panelists where Danny
Cohen, David L Parnas, Charles L Seitz, and Joseph Weizenbaum. The
moderator was Michael L Dertouzos.
I was basically disappointed in this panel discussion. I was hoping
to hear a good counter to the the arguments Dr Parnas had put forth
in his papers. Dr Cohen started what looked like an organized attack
on Dr Parnas' "Octet", refering to the series of eight papers Dr
Parnas presented his arguments in. Dr Cohen correctly dismissed the
eighth paper,"Is SDIO An Efficient Way To Fund Worthwhile Research",
as being outside the bounds of the current discussion. Unfortunately
Dr Cohen only further discussed one of the other papers. The other
six where dealt with with some minor hand waving. I have to admit I
don't remember which paper Dr Cohen "went into detail" on. This is
because the detail amounted to a one slide outline of the major six
points of this paper. This slide was up for no more than one minute
with some more hand waving that none of these points were true.
Back to the side claiming the software is not feasable, Dr Weizenbaum
didn't realy add much of anything to Dr Parnas' arguments. He thought
that Dr Parnas had done a wonderful job and there wasn't much he
could add. He gracefully didn't take up much time saying this either.
Dr Parnas basically presented the material in his papers. He added
the new point that even if we build this thing and it "tested OK",
we could never realy trust it and would be forced not to rely on it.
Charles Seitz made no attempt to directly attack Dr Parnas' argument.
He focused his presentation on a simplistic hierarchal structure the
software for SDI could take. Unfortuanately this looked like a highly
centralized form of controlling all the weapons and sensors resulting
in a high degree of complexity and size.
Both Dr Cohen and Seitz hit upon the point that the software for SDI
is not necessarily as large and complex as some people might think.
They claimed that it could be built of smaller fairly independant
parts. To me this appeared contradictory to Dr Seitz's hierarchal
control structure. It did come through that If you had enough
totally independant platforms shotting things down, you stood a good
change of hitting most the targets. It is also clear that you would
need a very high level of overkill to make this work since the other
platforms don't know who else is shotting at what.
Back to Dr Parnas' points, I did get the feeling that there is some
general agreement that there is a limit to the scale and complexity
our software engineering can handle. Dr Parnas furthered this point
by saying large advances in the mathematics of discreet functions
are going to be a major stumbling block in the furthering software
engineering. He doesn't expect these large advances on the grounds
that if you simplify the equations to much you are loosing
information. A discreet function can only represent so many bits.
I may not have this argument exactly right. He also went thru his
standing arguments against AI or automatic programing helping very
much.
[ I think the argument is that we need concise, manipulable
discrete functions modelling software in order to achieve what
other fields of engineering can do with concise, manipulable
continuous functions. However, such concise representations may
not be possible due to information-theoretic constraints on the
number of bits that can be represented by a certain number of
symbols. --MDAY@MIT-XX ]
[I didn't get quite this impression, though I agree with it. Rather, I
thought Parnas was saying that the problem was in the fact that with
software that is fundamentally digital, there is no such thing as a
continuous function, and that therefore the usual engineering
assumption valid in most of the world that small changes in input or
in correctness necessarily mean small changes in output or result
simply isn't valid in the software engineering world. Until it is
possible to analyze software in terms of approximately correct
functions, graceful software degradation (in terms of an approximately
correct program always doing approximately correct things) is not
really possible. -- LIN@MIT-MC]
Both sides came up with a number of interesting and colorful
analogies. The most relavent is the Space Shuttle. Dr Cohen claims
that the Space Shuttle works. This is obviously true in some sense.
However, it was also pointed out that there have been times when the
software on the shuttle has not worked within seconds of launch. It
seems that it would be impractical to ask the Soviets to wait 15
minutes while we reboot the system.
[Indeed, Seitz conceded that under certain circumstances plausible in
the context of a nuclear missile attack, it might be necessary to
re-boot the system. He then proceeed to ignore the consequences of
that; he did not even say that there are ways to eliminate the need
for re-booting. -- LIN@MIT-MC]
In summary it seems that there are very real limits on what our
software engineering can handle reliably. We are actually not that
far from those limits in some of our current efforts. If SDI is to
work its architecture must be dictated by what is doable by the
software. It is unclear that SDI is feasably from a material cost point
of view if the platforms are small and independant enough to be
reliable from the software standpoint.
In closing I would like to say that I don't think either side did a
particularly good job sticking to just the software feasibility
issue. One other interesting thing happened. Dr Parnas claimed to
have asked some person with authority over SDIO whether "No, we can't
do this" was an acceptable answer. He did this for the first time at
this debate because he did not want to say this behind this person's
back. Unfortunately, I don't remember this other person's name, but
he was in the audience. Dr Parnas claims that the answer was, "No is
not an accepatble answer" and challenged the other person to deny
this. The other person promptly stood up and did exactly
that.
[If you mean that it was political, that's certainly true. But
politics is really the determinant of the software specifications at
the top level. That is how it should be, and people who want to
ignore that are ignoring the most important part of the problem.
However, in other instances, the Administration has noted that the SDI
is central to future US defense policy. In addition, it has never
specified what evidence it would consider adequate or sufficient to
turn off the SDI.
-- LIN@MIT-MC]
------------------------------
Date: Mon 28 Oct 85 09:37:01-PST
From: Ole Jorgen Jacobsen <OLE@SRI-NIC.ARPA>
Subject: Falklands Game
A Mexican newspaper reports that bored Royal Air Force pilots stationed on
the Falkland Islands have devised what the consider a marvelous new game.
Noting that the local penguins are fascinated by airplanes, the pilots search
out a beach where the birds are gathered and fly slowly along it at the
water edge. Perhaps ten thousand penguins turn their heads in unison
watching the planes go by, and when the pilots turn around and fly back, the
birds turn their heads in the opposite direction, like spectators at a
slow-motion tennis match. Then, the paper reports "The pilots fly out to sea
and directly to the penguin colony and overfly it. Heads go up, up, up, and
ten thousand penguins fall over gently onto their backs.
-Audobon Magazine
------------------------------
Date: Mon, 28 Oct 85 14:04:54 EST
From: Will Martin <wmartin@brl.arpa>
Subject: Historical A-Bombs and a "what-if"
There has been a lot of WWII history on PBS TV and in other media lately,
and it inspired a thought... The island-hopping strategy of the Pacific
Theatre involved an awful lot of loss of life amongst the soldiers who
had to invade and take the islands held by the Japanese. Assuming that,
due to their conditioning and code, the Japanese defenders would have
died anyway, rather than surrender, no matter what techniques had been
used to neutralize the threat from these islands, it would have been
possible to have saved many thousands of lives (those of the Allied
soldiers and sailors who would NOT have had to run the risks of the
invasions) by using nuclear weapons to destroy the defending forces.
Of course, we did not HAVE nuclear weapons to use at the time the Marines
were dying on the beaches and in the jungles of these islands, and the
other services were losing men on ships, in the air, and on land during
these battles. But what if we HAD had enough nuclear weapons early
enough to have used them in this role? Would we have done it? What would
have been the result, both in the immediate aspects of the war, and in the
impacts on the post-war world? Would Japan have surrendered without
a nuclear strike on the home islands? (After all, it was proposed to
use the Hiroshima bomb as a demonstration weapon on an island instead
of making the first use be on a city; this was rejected at the time.
This would have been a series of "demonstrations", in effect.)
Or would we have used these weapons in Eurpoe instead? After all, we had
an explicit agreement amongst the Allies to make the defeat of Germany a
higher priority than the defeat of Japan. Would we have been compelled
to use nuclear bombs instead of massive conventional attacks on German
cities? Or would there have been enough voices raised against this use
of nuclear weapons against civilians that it would not have happened?
Or would it have happened *once*?
It seemed to me that many of the moral objections against using nuclear
weaponry do not apply when such use as reducing the defenses of an
isolated fortified island is considered. (Of course, some of these
islands DID have civilian populations -- I have never seen much
attention given to these peoples' fates and have assumed that they were
killed in bombardments and attacks, not haveing access to the defensive
positions of the Japanese military. Any pointers to info specifically on
them?) If I was in command of such an operation, and had the choice of
using a nuclear weapon and incinerating an entire island, turning it into
glass, versus sacrificing thousands of men in a conventional assault,
I'd not hesitate to nuke the island. But then I've never had to make any
such life-or-death decisions, so that is speculation.
I find this an intriguing speculation. If we had had a large stock of
nuclear weapons immediately after defeating both Germany and Japan (and
this might have happened earlier if we had used nuclear weapons earlier
[like 1943 or so]), I would think that our actions would have been
different at that time. Would we have attacked the Soviet Union, or
forced them to withdraw deep into Asiatic areas, leaving the
once-German-occupied territories as independent states? If Japan had
surrendered earlier, with less damage inflicted to the home islands,
would they have developed differently without the experience of
destruction and rebuilding to shape their outlook?
Speculation on this topic is solicited. Please send responses to the
Digest; mail to my home host has been flaky lately.
Regards, Will Martin
------------------------------
Date: 28 Oct 1985 1141-PST
From: Rem@IMSSS
CC: warack@AEROSPACE.ARPA
Subject:Are SLBMs safe?
| Date: Tue, 9 Jul 85 12:48:17 PDT
| From: Chris Warack <warack@AEROSPACE.ARPA>
| Subject: Questioning the need for SDI
| Over 50% of the US missiles are SLBM's and are not vulnerable to a
| pre-emptive strike by the USSR even accounting for the ones caught
| in port. This seems to be a common misconception -- that the USA is
| vulnerable to such an attack.
Submarines with missiles are an extreme case of multiple warheads in a
single silo. Whereas an MX missile with 10 warheads sits in one silo
that can be knocked out by one enemy warhead, on a submarine something
like 40 or more warheads can be knocked out by one enemy warhead if
the submarine can be located and tracked by the enemy missile. In the
past it has been assumed submarines can't be found in the big ocean,
and you are making that assumption, but recent advances in
satellite-based observation of the ocean are beginning to make that
assumption shaky, and maybe in a few years our submarines will be
totally unhideable. Furthermore, it isn't necessary to send an ICBM or
SLBM to knock out a submarine. Just attach a bomb to its side, after
all it isn't on homeland where you can't get at it, it's out there in
the middle of the ocean where anybody an come and go at will. All you
have to do is avoid being detected by the submarine itself. Since the
kill radius of a thermonuclear warhead against a submarine is perhaps
a mile or more, it shouldn't be too hard to just sit within kill
radius but outside direct detection radius. If the bomb is smaller
than the submarine, it may be that the submarine can be tracked from
space and locally from the bomb but the bomb can't be seen from either
space or from the sub.
| The policy of deterrence centers around surviving such an attack and being
| able to retaliate.
Yup. With single-warhead missiles that are less than 100% accurate,
the attacker spends more warheads than the victim loses, so the victim
wins the retaliation. But with multiple warhead missiles or multiple
missiles of any kind in a single silo or submarine this logic breaks
down when the silo/sub can be located.
| For this reason, we have concentrated our forces in SLBM's.
Until now. This may have to change in the near future.
| In fact, a number of opponents to ICBM's (and the MX in particular)
| feel our ICBM force should be deactivated anyways, since SLBM's carry more
| warheads with sufficient accuracy to be adequate for deterrence. In
| this light the Soviets are no better off than they are now.
I thought that way myself until a few years ago when I wrote to an
author of an article in Sci.Am. and got a reply to the effect that
soon submarines may be detectable and thus we ought not to put all our
missiles in subs, have some land-based and some aircraft-based too. (I
think this was about 4 years ago, so by now I expect the day when subs
can be located is getting close.)
| If SDI actually can replace deterrence in insuring national security, then
| what excuse is there not to disarm (nuclear)?
Flip answer: if horses can fly then why do we need airplanes??
Since SDI can't replace deterrence due to the instability we pass
through while building it and the insurmountable cost of ever really
getting it completed past the instable phase, then we still need
deterrence. But like Ike or somebody said, a couple hundred H-bombs
should be sufficient deterrence to protect us. (and I add, providing
the warheads are single-per-silo/sub)
------------------------------
Date: Mon, 28 Oct 85 17:11:58 EST
From: Herb Lin <LIN@MIT-MC.ARPA>
Subject: Test Ban
Date: Mon, 26 Aug 85 12:22 PDT
From: "Morton Jim" at LLL-MFE.ARPA
Concerning the Soviet Union offer for a complete moratorium on
Nuclear explosives testing, We entered into such an agreement
with them in the early sixties...
They abbrogated the treaty by beginning a very well planned
and executed series of tests....When
their projects were ready, they broke the
treaty and surged ahead with their research.
False. By the time the USSR broke the moratorium, the US had
*ALREADY* said it was no longer bound by it. Moreover, the SU said it
would feel free to resume when the "West" resumed testing, and the
French did so before the SU did.
------------------------------
Date: 29 Oct 85 07:42:42 EST (Tuesday)
From: MJackson.Wbst@Xerox.ARPA
Subject: Re: Build Your Own Bomb
The article was *not* "about how one can build a nuclear bomb in ones
home." You are thinking of "The H-Bomb Secret" by Howard Morland
(November 1979), which disclosed (in very general terms) technical
details about how, in a hydrogen bomb, the energy released by the
fission trigger is coupled to the fusion fuel, By "very general terms"
I mean "cartoon" drawings and word descriptions, but nothing like plans,
and no equations or critical numbers.
The US government bent considerable effort to block publication of this
article; the legal issues were never resolved, however, since
publication elsewhere made the issue moot.
The Morland article, later corrections, and an exhaustive discussion of
the legal case and related matters can be found in /Born Secret: The
H-Bomb, The *Progressive* Case, and National Security/, by A. DeVolpi et
al. (Pergamon Press, 1981).
Mark
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End of Arms-Discussion Digest
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