I think about this a lot because it’s true of any complex system or argument, not just software.

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 can't remember what Oxford did to resolve this, but I think they settled on `C.A.R. Hoare Residence`.

My favourite quote of his is “There are two ways of constructing a piece of software: One is to make it so simple that there are obviously no errors, and the other is to make it so complicated that there are no obvious errors.”

While we hope it's not true, if it is a very deserved RIP.

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.

"A consequence of this principle is that every occurrence of every subscript of every subscripted variable was on every occasion checked at run time against both the upper and the lower declared bounds of the array. Many years later we asked our customers whether they wished us to provide an option to switch off these checks in the interests of efficiency on production runs. Unanimously, they urged us not to they already knew how frequently subscript errors occur on production runs where failure to detect them could be disastrous. I note with fear and horror that even in 1980 language designers and users have not learned this lesson. In any respectable branch of engineering, failure to observe such elementary precautions would have long been against the law."

-- C.A.R Hoare's "The 1980 ACM Turing Award Lecture"

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

An older gentleman stood up and politely mentioned they knew a thing or two.

That was Tony Hoare.

I always liked this presentation. I think it's equally fine to say "invented" something, but I think this fits into his ethos (from what I understand of him.) There are natural phenomena, and it just takes noticing.

RIP Sir Tony.

Tony Hoare was on my bucket list of people I wanted to meet before I or they die. My grad school advisor always talked of him extremely highly, and while I cannot seem to confirm it, I believe Hoare might have been his PhD advisor.

It's hard to overstate how important Hoare was. CSP and Hoare Logic and UTP are all basically entire fields in their own right. It makes me sad he's gone.

Makes me think of an anecdote where Dijkstra said that he feared he would only be remembered for his shortest path algorithm.

Mr. Hoare did a talk back during my undergrad and for some reason despite totally checked out of school I attended, and it is one of my formative experiences. AFAICR it was about proving program correctness.

After it finished during the Q&A segment, one student asked him about his opinions about the famous Brooks essay No Silver Bullet and Mr. Hoare's answer was... total confusion. Apparently he had not heard of the concept at all! It could be a lost in translation thing but I don't think so since I remember understanding the phrase "silver bullet" which did not make any sense to me. And now Mr. Hoare and Dr. Brooks are two of my all time computing heroes.

> Another good example of recursion is quicksort, a sorting algorithm developed by C.A.R. Hoare in 1962. Given an array, one element is chosen and the others partitioned in two subsets - those less than the partition element and those greater than or equal to it. The same process is then applied recursively to the two subsets. When a subset has fewer than two elements, it doesn't need any sorting; this stops the recursion.

> Our version of quicksort is not the fastest possible, but it's one of the simplest. We use the middle element of each subarray for partitioning. [...]

It was one of the first few 'serious' algorithms I learnt to implement on my own. More generally, the book had a profound impact on my life. It made me fall in love with computer programming and ultimately choose it as my career. Thanks to K&R, Tony Hoare and the many other giants on whose shoulders I stand.

In the 60s inventing one single algorithm with 10 lines of code was a thing.

If you did that today nobody would bat an eye.

Today people write game engines, compilers, languages, whole OS and nobody bats an eye cause there are thousands of those.

Quick sort isn't even a thing for leet code interviews anymore because it's not hard enough.

It had intrigued me due to its promise of designing lock-free concurrent systems, that can (I think) also be proven to be deadlock-free.

You do this by building a simple concurrent block that is proven to work correctly, and then build bigger ones using the smaller, proven blocks, to create more complex systems.

The way it is designed is processes don't share data and don't have locks. They use synchronized IPC for passing and modifying data. It seemed to be a foundational piece for designing reliable systems that incorporate concurrency in them.

249 points by nextos 16 hours ago | 61 comments

His presentation on his billion dollar mistake is something I still regularly share as a fervent believer that using null is an anti-pattern in _most_ cases. https://www.infoq.com/presentations/Null-References-The-Bill...

That said, his contributions greatly outweigh this 'mistake'.

> On the topic of films, I wanted to follow up with Tony a quote that I have seen online attributed to him about Hollywood portrayal of geniuses, often especially in relation to Good Will Hunting. A typical example is: "Hollywood's idea of genius is Good Will Hunting: someone who can solve any problem instantly. In reality, geniuses struggle with a single problem for years". Tony agreed with the idea that cinema often misrepresents how ability in abstract fields such as mathematics is learned over countless hours of thought, rather than - as the movies like to make out - imparted, unexplained, to people of 'genius'. However, he was unsure where exactly he had said this or how/why it had gotten onto the internet, and he agreed that online quotes on the subject, attributed to him, may well be erroneous.

Somewhat off-topic, but it's cool hearing this from someone who's contributed so much to the fields of programming and mathematics. It makes me hopeful that my own strugglings with math will pay out over time!

he read the algol 60 report (Naur, McCarthy, Perlis, …)

and that described "recursion"

=> aaah!

https://www.youtube.com/watch?v=pJgKYn0lcno

SIR_TONY_HOARE = μX • (think → create → give → X)

-- process ran from 1934 to 2026 -- terminated with SKIP -- no deadlock detected -- all assertions satisfied -- trace: ⟨ quicksort, hoare_logic, csp, monitors, -- dining_philosophers, knighthood, turing_award, -- billion_dollar_apology, structured_programming, -- unifying_theories, ... ⟩ -- trace length: ∞ The channel is closed. The process has terminated. The algebra endures.

Virtual HLF 2020 – Scientific Dialogue: Sir C. Antony R. Hoare/Leslie Lamport

https://www.youtube.com/watch?v=wQbFkAkThGk

When I started university he gave a talk to all the new CompScis which as you can imagine was incredibly inspirational for an aspiring Software Engineer.

Grateful to have had that experience.

RIP

See the "preface" for details of the book - https://dl.acm.org/doi/10.1145/3477355.3477356

Review of the above book - https://www.researchgate.net/publication/365933441_Review_on...

Somebody needs to contact ACM and have them make the above book freely available now; there can be no better epitaph.

2) Tony Hoare's lecture in honour of Edsger Dijkstra (2010); What can we learn from Edsger W. Dijkstra? - https://www.cs.utexas.edu/~EWD/DijkstraMemorialLectures/Tony...

Somebody needs to now write a similar one for Hoare.

Truly one of the absolute greats in the history of Computer Science.

This is how you remind me of what I really am This is how you remind me of what I really am

It's not like you to say sorry I was waitin' on a different story This time I'm mistaken For handing you a heart worth breakin' And I've been wrong, I've been down Been to the bottom of every bottle These five words in my head Scream, "Are we havin' fun yet?"

Yet, yet, yet, no, no Yet, yet, yet, no, no

It's not like you didn't know that I said, "I love you," and I swear I still do And it must have been so bad 'Cause livin' with me must have damn near killed you

And this is how you remind me of what I really am This is how you remind me of what I really am

It's not like you to say sorry I was waitin' on a different story This time I'm mistaken For handing you a heart worth breakin' And I've been wrong, I've been down Been to the bottom of every bottle These five words in my head Scream, "Are we havin' fun yet?"

Yet, yet, yet, no, no Yet, yet, yet, no, no Yet, yet, yet, no, no Yet, yet, yet, no, no

Never made it as a wise man I couldn't cut it as a poor man stealin' And this is how you remind me This is how you remind me

This is how you remind me of what I really am This is how you remind me of what I really am

It's not like you to say sorry I was waitin' on a different story This time I'm mistaken For handing you a heart worth breakin' And I've been wrong, I've been down Been to the bottom of every bottle These five words in my head Scream, "Are we havin' fun yet?"

Yet, yet, are we havin' fun yet? Yet, yet, are we havin' fun yet? Yeah, yeah (These five words in my head scream) Are we havin' fun yet? Yeah, yeah (These five words in my head) No, no

RIP good sir

Can anyone suggest a better approach for a situation like this in the future? What's better than exposing addressing the problem with a light solution?

Turing Award Legend.

Thank you for your work on ALGOL, you were multiple decade ahead of your time.

Rest in peace.