[ih] A bit more re John McCarthy
Jack Haverty
jack at 3kitty.org
Thu Jun 25 11:42:08 PDT 2026
One additional historical tidbit that Gemini missed...
The PDP-10 instruction set included ROTC - ROTateCombined - which
treated two registers as a single memory location and ROTated bits
between the two. IIRC bits ROTated off the right end of one register
were moved into the right side of the adjacent register. Same migration
for the other sides, so the 2 registers behaved as one circular register
twice as wide. This was used in Greenblatt's Chess program in one of
the "inner loops" that dictated performance. I suspect ROTC might have
been used in the "transposition table" manipulations.
Greenblatt at one point decided it would also be useful for Chess to
have a different instruction available - where the bits rotated out the
right end went into the LEFT side of the adjacent register.
So one day shortly thereafter the AI's PDP-10 suddenly had a new
instruction, which rotated 2 registers "the other way". I don't
remember what mnemonic they used. I was in Lick's group, and our PDP-10
didn't get that modification so I never used that instruction.
This was all possible because the PDP-10s used "flip chips" containing
logic gates, all interconnected by a massive "bed of nails" backplane.
The CPU was contained in a very large standard DEC cabinet. So it was
straightforward to change how the CPU worked. If you knew what you were
doing you could even add new instructions. DEC Field Service
technicians hated coming to fix MIT machines. But loved to learn more
about how the machines actually worked.
With today's technology, all that design is now embedded in the silicon
wafers, so it would be much much more difficult to do such things.
/Jack Haverty
On 6/25/26 02:36, Vint Cerf via Internet-history wrote:
> Steve Crocker and I spent some time understanding a chess program written
> by Richard Greenblatt at MIT in the mid/late 1960s. Not sure how that
> program may have been influenced by earlier work. From Gemini:
>
> Alan Kotok, a fellow MIT hacker, wrote an earlier chess program which
> inspired Greenblatt.
>
> The program Richard Greenblatt wrote is famously known as *Mac Hack VI* (or
> simply *Mac Hack* / *The Greenblatt Chess Program*). Developed at the MIT
> Artificial Intelligence Laboratory starting in November 1966, it is a
> milestone in the history of AI and computer chess.
>
> Here is a breakdown of what made Mac Hack VI so significant:
> 1. Historical Milestones
>
> -
>
> *Human Tournament Play:* In January 1967, Mac Hack VI became the very
> first computer program to play against humans under regular tournament
> conditions (competing in the Massachusetts Amateur Championship).
> -
>
> *Official Chess Rating:* It was the first chess engine to be granted an
> official chess rating by the United States Chess Federation (USCF),
> initially clocking in around 1200–1400 (the level of a decent hobbyist or
> high school player).
> -
>
> *First Human Defeat:* In the spring of 1967, it became the first
> computer program to defeat a human in a sanctioned tournament setting,
> beating a player rated 1510 USCF.
> -
>
> *The Hubert Dreyfus Match:* Famously, philosopher and prominent AI
> skeptic Hubert Dreyfus—who had publicly asserted that no computer could
> ever defeat even a child at chess—was invited to the MIT lab. Mac Hack
> VI promptly defeated him, a moment that became legendary in early AI lore.
>
> 2. Technical Innovations
>
> -
>
> *The Transposition Table:* Mac Hack VI was the first chess program to
> implement a transposition table. This optimization caches previously
> evaluated board positions, ensuring the computer doesn't waste precious
> processing power re-calculating the same position if arrived at via a
> different sequence of moves.
> -
>
> *Better Chess Heuristics:* Unlike earlier creators of chess programs who
> weren't particularly strong players themselves, Richard Greenblatt was an
> accomplished chess player. He added roughly 50 specialized heuristics
> (rules of thumb) directly into the code to evaluate positions pragmatically.
> -
>
> *Programming Language:* It was written entirely in *MIDAS* (a macro
> assembler language) for the DEC PDP-6 computer. It evaluated about 10
> positions per second, a fraction of what modern engines do, but used clever
> "plausible move generation" to narrow down which branches of the game tree
> to search.
>
> 3. Legacy
>
> Mac Hack VI went on to be widely distributed after being ported to the
> PDP-10. It laid the architectural groundwork for many generation-defining
> chess engines that followed. Interestingly, a decade later in 1977, the
> program even got to play three games against grandmaster Bobby Fischer
> (though Fischer predictably won all three).
>
>
>
> On Thu, Jun 25, 2026 at 1:12 AM Leonard Kleinrock via Internet-history <
> internet-history at elists.isoc.org> wrote:
>
>> Back to the early history involving the brilliance of John McCarthy: For
>> example, it is not widely known that in 1958/59 John McCarthy and Claude
>> Shannon began working on a limited chess playing program. McCarthy engaged
>> a graduate student named Paul Abrahams and they took on the task of
>> generating all legal moves from any given chess position. Shannon hired me
>> to work with him and it was our job to generate strategies for the middle
>> game. In that role, among other strategies, we studied a book by Fred
>> Reinfeld “1001 brilliant chess sacrifices and combinations” where each page
>> showed a middle game position for which there was a brilliant move or a
>> sequence of moves and the challenge was to find it. We went to the answers
>> in the back of the book and gathered statistics on such data as “what is
>> the most common first move of brilliant sequence?“. (the answer is,
>> unsurprisingly “check“!). Using such data, we generated a fairly
>> interesting program to play portions of the middle game of chess. Shortly
>> thereafter, Alan Kotok, Elwyn Berlekamp and other MIT students used some of
>> these ideas which led to the MIT chess playing program.
>> As another example, we all remember that McCarthy created LISP (and the
>> same Paul Abrahams was again involved) and McCarthy also introduced some
>> essential ideas of time sharing.
>> Between John McCarthy and Marvin Minsky the field of AI had its early
>> beginnings.
>> Len
>> Sent from my iPhone
>>
>>
>>> On Jun 24, 2026, at 5:36 PM, Brian E Carpenter via Internet-history <
>> internet-history at elists.isoc.org> wrote:
>>> On 25-Jun-26 10:22, Sivan via Internet-history wrote:
>>>> Dear Jack Haverty,
>>>> Your question "For example, when there are problems in today's Internet,
>>>> are AI techniques and tools used to diagnose and repair them? What's
>> the
>>>> History of such things?" is immensely interesting. Concerns about A.I.
>>>> momentarily set aside, are there initiatives underway to positively use
>>>> A.I. tools to "diagnose and repair" problems in the Internet? For
>> example,
>>>> using A.I. to scan for malware, bots, phishing and other forms of
>> technical
>>>> and non-technical Abuse? Or using A.I. to scan and detect barriers to
>>>> network protocols such as vpns? Or even using A.I. to scan and detect
>>>> non-human content and other forms of Abuse?
>>> I can't imagine that the answer to any of those questions is "No".
>>> I wouldn't have said that a year ago, but progress is very fast.
>>>
>>> Of course, operators will see this as a competitive advantage and may
>>> choose not to publicise such AI deployments. But there is a lot of
>>> work in progress on agent-to-agent communication.
>>>
>>> If this is history, it's history in progress.
>>>
>>> Regards/Ngā mihi
>>> Brian Carpenter
>>>
>>>> Sivasubramanian Muthusamy
>>>> sender
>>>>> On Tue, 23 Jun, 2026, 01:20 Jack Haverty via Internet-history, <
>>>>> internet-history at elists.isoc.org> wrote:
>>>>> With AI now in the news all the time, I've been wondering about the
>>>>> history of AI in The Internet, i.e., how AI technology has been used
>>>>> within the Internet over the years, rather than just a service which
>>>>> people can access over The Internet. Personally I only know of a few
>>>>> such uses of AI in a communications role, quite a while ago. But maybe
>>>>> others remember more...?
>>>>> In the mid-1970s, I was involved in an AI project at MIT in Licklider's
>>>>> group, sponsored by ARPA. It wasn't really part of the ARPANET but it
>>>>> did relate to communications. The project involved using AI
>> techniques
>>>>> of that era, then called "expert systems", to have computers decode
>>>>> hand-sent Morse radio transmissions. The Intelligence Community was
>>>>> apparently quite interested in this problem at that time, and the
>>>>> project ran for several years and was deemed a success.
>>>>> FYI, see chapter 22 of https://apps.dtic.mil/sti/citations/ADA239925
>> for
>>>>> info on that AI project. Personally, I think of that 1990 report as an
>>>>> enumeration of "ARPA's Greatest Hits". There are six projects listed
>>>>> from the Information Processing Techniques Office of ARPA (IPTO, where
>>>>> all the networking and computer projects happened). Another project of
>>>>> those six IPTO successes is The ARPANET, described in Chapter 20. The
>>>>> Internet was probably still too immature to be included at the time .
>>>>> Similarly, while I was at BBN in the 1980s there were tools developed
>> to
>>>>> visualize activity in the ARPANET, and do tasks involved in network
>>>>> design - figuring out where new lines were needed, reconfiguring the
>>>>> topology of the ARPANET to address changes in traffic patterns, and
>>>>> other such analyses. I'm not sure those projects would be recognized
>> as
>>>>> "AI" today, but they were widely used to manage a variety of networks
>>>>> such as the ARPANET and DDN. The idea was to use computers to augment
>>>>> people skills, as it is in today's AI as well.
>>>>> Bob Kahn and I had a discussion at some point in late 1982 about AI and
>>>>> networks in ARPA's world. Bob was aware of the ARPA-sponsored project
>>>>> done at MIT in the mid 1970s which used AI "expert system" techniques
>> to
>>>>> decode Morse code. We mused that a similar expert system approach
>>>>> could be used to manage networks, especially the emerging Internet
>> which
>>>>> was much more complex than the ARPANET and had few tools available for
>>>>> operations and management.
>>>>> The concept was to use the plentiful supply of BBN engineers who had
>>>>> been debugging Internet crises for several years as the "experts",
>>>>> observing how they worked, and translating what they did into software
>>>>> to do tasks "automatically". That started the "Automated Network
>>>>> Management" (ANM) project as a new research task at BBN. I wrote the
>>>>> proposal to ARPA and waited for the contract to be signed. But when
>> BBN
>>>>> reorganized in July 1983 the ANM contract and I went separate ways so I
>>>>> never got to work on ANM and I don't think there was enough detail in
>>>>> the proposal to convey the concept onwards to the new project team.
>>>>> It strikes me that the real driver of AI today has evolved only partly
>>>>> from advances in algorithms such as LLMs. I think another major factor
>>>>> has been the massive drop in computing costs over the last
>>>>> half-century. AI systems, such as that Morse Code project, were
>>>>> affordable only by well-funded parts of government in the 1970s,
>>>>> requiring millions of dollars/pounds/rubles/yen/lira to field a system
>>>>> that provided minimal capability. Today, the system that cost millions
>>>>> in the 1970s now costs pennies by comparison.
>>>>> Anybody else know more about the history of the use of AI *within* (not
>>>>> just on top of) The Internet? For example, when there are problems in
>>>>> today's Internet, are AI techniques and tools used to diagnose and
>>>>> repair them? What's the History of such things?
>>>>> /Jack Haverty
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