One of my favorite quotes:
“There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies.”
I think about this a lot because it’s true of any complex system or argument, not just software.
This is indeed a great quote (one of many gems from Sir Tony) but I think the context that follows it is also an essential insight:
> The first method is far more difficult. It demands the same skill,
devotion, insight, and even inspiration as the discovery of the simple
physical laws which underlie the complex phenomena of nature. It
also requires a willingness to accept objectives which are limited
by physical, logical, and technological constraints, and to accept a
compromise when conflicting objectives cannot be met. No committee
will ever do this until it is too late.
"At first I hoped that such a technically unsound project would collapse but I soon realized it was doomed to success. Almost anything in software can be implemented, sold, and even used given enough determination. There is nothing a mere scientist can say that will stand against the flood of a hundred million dollars. But there is one quality that cannot be purchased in this way-- and that is reliability. The price of reliability is the pursuit of the utmost simplicity. It is a price which the very rich find most hard to pay."
From the linked lecture, which I printed out to read as part of a new less is more screen time management regime (where I print out longer form writing for reading) I found this very interesting tidbit in the context of Tony having made a delivery miscalculation and his team failing to deliver on one of their products; which is where I think a lot people are today with LLMs:
"Each of my managers explained
carefully his own theory of what had gone wrong and all the theories were different. At last, there breezed into my office the most senior manager of all, a general manager of our parent company, Andrew St. Johnston. I was surprised that he had even heard of me.
"You know what went wrong?" he shouted--he always shouted -- "You let your programmers do things which you yourself do not understand." I stared in astonishment. "
Can’t argue with the quote. However my current boss has been pushing this to the extreme without much respect for real-world complexities (or perhaps I’m too obtuse to think of a simple solution for all our problems), which regrettably gives me a bit of pause when hearing this quote.
Reminds me of this quote... “A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work.”
One of the policies of The Rhinoceros Party in Canada was to increase the complexity of the taxation system so much that nobody could find the loopholes to exploit.
Had to look them up (WP), wasn't disappointed. We have the Monster Raving Loony Party in the UK.
One of the Rhino's Party policies stands out - are you sure Trump wasn't born a Cannuck and was stolen at birth by racoons and smuggled down south?
"Annexing the United States, which would take its place as the third territory in Canada's backyard (after the Yukon and the Northwest Territories—Nunavut did not yet exist), in order to eliminate foreign control of Canada's natural resources"
As Dijkstra was preparing for his end of life, organizing his documents and correspondence became an important task. Cancer had snuck up on him and there was not much time.
One senior professor, who was helping out with this, asked Dijkstra what is to be done with his correspondences. The professor, quite renowned himself, relates a story where Dijsktra tells him from his hospital bed, to keep the ones with "Tony" and throw the rest.
The professor adds with a dry wit, that his own correspondence with Dijsktra were in the pile too.
Time of delivery would be the biggest factor. Today we can send multiple quick messages to anyone, at that time people had to batch big discussions in a long articulated text, since it would take days to it arrive.
I guess the closest to that nowadays would be blog articles, RFC discussions or long-form email threads.
Fun story - at Oxford they like to name buildings after important people. Dr Hoare was nominated to have a house named after him. This presented the university with a dilemma of having a literal `Hoare house` (pronounced whore).
I can't remember what Oxford did to resolve this, but I think they settled on `C.A.R. Hoare Residence`.
>our Reinforcement Learning reading group there //
Anyone else, like me, imagining ML models embodied as Androids attending what amounts to a book club? (I can't quite shake the image of them being little CodeBullets with CRT monitors for heads either.)
Our Graphics Lab at University used to be in an old house opposite a fish and chip shop. The people at the fish and chip shop were suspicious of our lab as all they saw was young men (mostly) entering and leaving at all hours of the night. We really missed an opportunity to name it "Hoare House" after one of our favourite computer scientists.
I mean, I like puns but they're a flash in the pan. Jokes get old after a while and you don't want to embed them in something fairly permanent like a building name.
Imagine being a world-famous computer scientist and dying and one of the top threads in a discussion of your life is juvenile crap about how your name sounds like "whore".
He was the professor in the Programming Research Group (known universally as the PRG) at Oxford when I was doing my DPhil and interviewed me for the DPhil. I spent quite a bit of time with him and, of course, spent a lot of time doing stuff with CSP including my entire DPhil.
Sad to think that the TonyHoare process has reached STOP.
I lucked in to meeting him once, in Cambridge. A gentle intellectual giant.
I repeatedly borrow this quote from his 1980 Turing Award speech, 'The Emperor's Old Clothes'... "At last, there breezed into my office the most senior manager of all, a general manager of our parent company, Andrew St. Johnston. I was surprised that he had even heard of me. "You know what went wrong?" he shouted--he always shouted-- "You let your programmers do things which you yourself do not understand." I stared in astonishment. He was obviously out of touch with present day realities. How could one person ever understand the whole of a modern software product like the Elliott 503 Mark II software system? I realized later that he was absolutely right; he had diagnosed the true cause of the problem and he had planted the seed of its later solution."
My interpretation is that whether shifting from delegation to programmers, or to compilers, or to LLMs, the invariant is that we will always have to understand the consequences of our choices, or suffer the consequences.
"Around Easter 1961, a course on ALGOL 60 was offered in Brighton, England, with Peter Naur, Edsger W. Dijkstra, and Peter Landin as tutors. I attended this course with my colleague in the language project, Jill Pym, our divisional Technical Manager, Roger Cook, and our Sales Manager, Paul King. It was there that I first learned about recursive procedures and saw how to program the sorting method which I had earlier found such difficulty in explaining. It was there that I wrote the procedure, immodestly named Quicksort, on which my career as a computer scientist is founded. Due credit must be paid to the genius of the designers of ALGOL 60 who included recursion in their language and enabled me to describe my invention so elegantly to the world. I have regarded it as the highest goal of programming language design to enable good ideas to be elegantly expressed."
- C.A.R Hoare, The Emperor's Old Clothes, Comm. ACM 24(2), 75-83 (February 1981).
Tony's An Axiomatic Basis for Computer Programming[1] is the first academic paper that I read that I was able to understand when I was an undergrad. I think it unlocked something in me because before that I never believed that I would be able to read and understand scientific papers.
That was 35ish years ago. I just pulled up the paper now and I can't read the notation anymore... This might be something that I try applying an AI to. Get it to walk me through a paper paragraph-by-paragraph until I get back up to speed.
Retrospective: An Axiomatic Basis For Computer Programming. This was written 30 years after An Axiomatic Basis for Computer Programming to take stock on what was proven right and what was proven wrong - https://cacm.acm.org/opinion/retrospective-an-axiomatic-basi...
Thanks for the recommendation. I downloaded both social.pdf and noproof.pdf on my Kindle Scribe to read them carefully and revisited the discussions on EWD638 and EWD692.
It is very interesting to see how Sir Tony diverged from EDW: one is right in theoretical sense but cynical about human fallacies and how the society is heading towards more wasteful complexity, one is to live with it and stay optimistic.
There is a proverb in Chinese Taoism:
小隱隱於野，大隱隱於市
A small recluse hides in the wild, while a great recluse hides in the city
He also invented many other things, like enumeration types, optional types, constructors. He popularized the "unions" introduced by McCarthy, which were later implemented in ALGOL 68, from where a crippled form of them was added to the C language.
Several keywords used in many programming languages come from Hoare, who either coined them himself, or he took them from another source, but all later programming language designers took them from Hoare. For example "case", but here only the keyword comes from Hoare, because a better form of the "case" statement had been proposed first by McCarthy many years earlier, under the name "select".
Another example is "class" which Simula 67, then all object-oriented languages took from Hoare, However, in this case the keyword has not been used first by Hoare, because he took "class", together with "record", from COBOL.
Another keyword popularized by Hoare is "new" (which Hoare took from Wirth, but everybody else took from Hoare), later used by many languages, including C++. At Hoare, the counterpart of "new" was "destroy", hence the name "destructor", used first in C++.
The paper "Record Handling", published by C.A.R. Hoare in 1965-11 was a major influence on many programming languages. It determined significant changes in the IBM PL/I programming language, including the introduction of pointers . It also was the source of many features of the SIMULA 67 and ALGOL 68 languages, from where they spread in many later programming languages.
The programming language "Occam" has been designed mainly as an implementation of the ideas described by Hoare in the "Communicating Sequential Processes" paper published in 1978-08. OpenMP also inherits many of those concepts, and some of them are also in CUDA.
The mistake was not null references per se. The mistake was having all references be implicitly nullable.
He states around minute 25 the solution to the problem is to explicitly represent null in the type system, so nullable pointers are explicitly declared as such. But it can be complex to ensure that non-nullable references are always initialized to a non-null value, which is why he chose the easy solution to just let every reference be nullable.
The null reference was invented by Hoare as a means to implement optional types, which works regardless of their binary representation.
Optional types were a very valuable invention and the fact that null values have been handled incorrectly in many programming languages or environments is not Hoare's fault.
I'm pretty sure that this is not true. I talked to Bud Lawson (the inventor of the pointer) and he claimed that they had implemented special behaviour for null pointers earlier. When I talked to Tony later about it, he said he had never heard of Bud Lawson. So probably both invented them independently, but Bud came first.
there was a time, 10-15 years ago, when they were super cool. at some point they """diluted""" the technicality content and the nature of guests and they vanished into irrelevance.
Readit News
I think about this a lot because it’s true of any complex system or argument, not just software.
> The first method is far more difficult. It demands the same skill, devotion, insight, and even inspiration as the discovery of the simple physical laws which underlie the complex phenomena of nature. It also requires a willingness to accept objectives which are limited by physical, logical, and technological constraints, and to accept a compromise when conflicting objectives cannot be met. No committee will ever do this until it is too late.
(All from his Turing Award lecture, "The Emperor's Old Clothes": https://www.labouseur.com/projects/codeReckon/papers/The-Emp...)
This explain quite a lot actually!
"Each of my managers explained carefully his own theory of what had gone wrong and all the theories were different. At last, there breezed into my office the most senior manager of all, a general manager of our parent company, Andrew St. Johnston. I was surprised that he had even heard of me.
"You know what went wrong?" he shouted--he always shouted -- "You let your programmers do things which you yourself do not understand." I stared in astonishment. "
The software I like best was not written by "teams"
I prefer small programs written by individuals that generally violate memes like "software is never finished" and "all software has bugs"
(End user perspective, not a developer)
Tony might be my favorite computer scientist.
I've been thinking about it a lot, and now, in turn, the memory of Mr. Hoare.
don't bet on it
https://www.npr.org/sections/13.7/2014/02/03/270680304/this-...
Antoine de Saint-Exupéry
The book is well worth reading.
https://news.ycombinator.com/item?id=9948767
One of the Rhino's Party policies stands out - are you sure Trump wasn't born a Cannuck and was stolen at birth by racoons and smuggled down south?
"Annexing the United States, which would take its place as the third territory in Canada's backyard (after the Yukon and the Northwest Territories—Nunavut did not yet exist), in order to eliminate foreign control of Canada's natural resources"
One senior professor, who was helping out with this, asked Dijkstra what is to be done with his correspondences. The professor, quite renowned himself, relates a story where Dijsktra tells him from his hospital bed, to keep the ones with "Tony" and throw the rest.
The professor adds with a dry wit, that his own correspondence with Dijsktra were in the pile too.
I guess back then each letter had a cost, in (delivery) time and money, so you better make it count.
My guess is that these correspondences were often interesting to read because they had to be worthwile to send because of the associated cost.
I guess the closest to that nowadays would be blog articles, RFC discussions or long-form email threads.
I can't remember what Oxford did to resolve this, but I think they settled on `C.A.R. Hoare Residence`.
[1] https://www.cs.ox.ac.uk/people/jennifer.watson/tonyhoare.htm...
Anyone else, like me, imagining ML models embodied as Androids attending what amounts to a book club? (I can't quite shake the image of them being little CodeBullets with CRT monitors for heads either.)
The University was correct in saying "nope" to the endless distractions, misery, and overhead of having to deal with that.
Sad to think that the TonyHoare process has reached STOP.
RIP.
I repeatedly borrow this quote from his 1980 Turing Award speech, 'The Emperor's Old Clothes'... "At last, there breezed into my office the most senior manager of all, a general manager of our parent company, Andrew St. Johnston. I was surprised that he had even heard of me. "You know what went wrong?" he shouted--he always shouted-- "You let your programmers do things which you yourself do not understand." I stared in astonishment. He was obviously out of touch with present day realities. How could one person ever understand the whole of a modern software product like the Elliott 503 Mark II software system? I realized later that he was absolutely right; he had diagnosed the true cause of the problem and he had planted the seed of its later solution."
My interpretation is that whether shifting from delegation to programmers, or to compilers, or to LLMs, the invariant is that we will always have to understand the consequences of our choices, or suffer the consequences.
It would have been fun if he’d directly said “You’re absolutely right!”
That was 35ish years ago. I just pulled up the paper now and I can't read the notation anymore... This might be something that I try applying an AI to. Get it to walk me through a paper paragraph-by-paragraph until I get back up to speed.
[1]:https://dl.acm.org/doi/10.1145/363235.363259
Retrospective: An Axiomatic Basis For Computer Programming. This was written 30 years after An Axiomatic Basis for Computer Programming to take stock on what was proven right and what was proven wrong - https://cacm.acm.org/opinion/retrospective-an-axiomatic-basi...
How Did Software Get So Reliable Without Proof? More detailed paper on the above theme (pdf) - https://6826.csail.mit.edu/2020/papers/noproof.pdf
It is very interesting to see how Sir Tony diverged from EDW: one is right in theoretical sense but cynical about human fallacies and how the society is heading towards more wasteful complexity, one is to live with it and stay optimistic.
There is a proverb in Chinese Taoism:
小隱隱於野，大隱隱於市
A small recluse hides in the wild, while a great recluse hides in the city
1. https://notebooklm.google/
Several keywords used in many programming languages come from Hoare, who either coined them himself, or he took them from another source, but all later programming language designers took them from Hoare. For example "case", but here only the keyword comes from Hoare, because a better form of the "case" statement had been proposed first by McCarthy many years earlier, under the name "select".
Another example is "class" which Simula 67, then all object-oriented languages took from Hoare, However, in this case the keyword has not been used first by Hoare, because he took "class", together with "record", from COBOL.
Another keyword popularized by Hoare is "new" (which Hoare took from Wirth, but everybody else took from Hoare), later used by many languages, including C++. At Hoare, the counterpart of "new" was "destroy", hence the name "destructor", used first in C++.
The paper "Record Handling", published by C.A.R. Hoare in 1965-11 was a major influence on many programming languages. It determined significant changes in the IBM PL/I programming language, including the introduction of pointers . It also was the source of many features of the SIMULA 67 and ALGOL 68 languages, from where they spread in many later programming languages.
The programming language "Occam" has been designed mainly as an implementation of the ideas described by Hoare in the "Communicating Sequential Processes" paper published in 1978-08. OpenMP also inherits many of those concepts, and some of them are also in CUDA.
His “billion dollar mistake”:
https://www.infoq.com/presentations/Null-References-The-Bill...
He states around minute 25 the solution to the problem is to explicitly represent null in the type system, so nullable pointers are explicitly declared as such. But it can be complex to ensure that non-nullable references are always initialized to a non-null value, which is why he chose the easy solution to just let every reference be nullable.
Optional types were a very valuable invention and the fact that null values have been handled incorrectly in many programming languages or environments is not Hoare's fault.
there was a time, 10-15 years ago, when they were super cool. at some point they """diluted""" the technicality content and the nature of guests and they vanished into irrelevance.
Hoare Logic - https://en.wikipedia.org/wiki/Hoare_logic
However, they were not just concurrent, but also communicating.