Top all-time · #2404
keeping simple
Personal blog · yodaiken.comsystemsprogrammingscience
keeping simple is a personal blog at yodaiken.com about systems, programming and science. Since 2016, 34 different Hacker News readers have linked it 68 times, most often “Undefined behavior in C is a reading error”. It is still writing: the last post was on 2026-09-01, and you can follow it by feed.
Most-linked posts?
- Undefined behavior in C is a reading error5 people · 5 mentions · first linked 2021-05-19
- /2018/06/07/torvalds-on-aliasing/4 people · 4 mentions · first linked 2021-03-20
- C Standard Undefined Behavior vs. Wittgenstein [pdf]4 people · 4 mentions · first linked 2018-05-30
- The C standard versus C and the mother of all hacks (2017)3 people · 3 mentions · first linked 2017-06-27
- Dennis Ritchie on alias analysis in C (1988)3 people · 3 mentions · first linked 2021-03-19
- Computer Science as a Scholarly Discipline2 people · 4 mentions · first linked 2016-12-24
- Undefined behavior and purpose of C language2 people · 2 mentions · first linked 2017-01-05
- Depressing and faintly terrifying days for the C standard [pdf]2 people · 2 mentions · first linked 2018-05-30
- Von Neumann’s critique of automata theory and logic in computer science (1947)2 people · 2 mentions · first linked 2019-05-25
- Linus Torvalds on aliasing2 people · 2 mentions · first linked 2018-06-08
What Hacker News says?
truly ahead of his time https://www.yodaiken.com/2019/02/20/von-neumanns-critique-of...
Comment linking /2019/02/20/von-neumanns-critique-of-automata-theory-and-logic-in-computer-science/
on “The Unparalleled Genius of John von Neumann (2019)”Submitted Depressing and faintly terrifying days for the C standard [pdf] as a story · 209 points
HN discussionI think the answer is that in the late 80s/90s, academic CS decided that the important topics in this area centered on completely asynchronous networks. The super famous, but trivial, FLP "theorem" gave a respectable foundation for work in the area (even though it pretty much says, you can't get anywhere with a completely asynchronous network). There was a lot of very interesting work prior to this period that was j…
Comment linking /2018/07/16/practical-uses-of-synchronized-clocks-liskov/
on “The Paxos Algorithm, or How to Win a Turing Award”Submitted Undefined behavior in C is a reading error as a story · 203 points
HN discussionYou don't need Paxos at all. In fact, you should read Liskov's paper https://www.yodaiken.com/2018/07/16/practical-uses-of-synchr... The key is to decide whether timeouts work in your network. If timeouts don't work and you don't have some reliable message protocol, then nothing works. If timeouts do work, then a completely simple obvious brute force algorithm works. In this algorithm, we have leader/coordinator ele…
Comment linking /2018/07/16/practical-uses-of-synchronized-clocks-liskov/
on “The Paxos Algorithm, or How to Win a Turing Award”Submitted Linus Torvalds on aliasing as a story · 150 points
HN discussionThis is authentically a very interesting simulation and I would be interesting to see a writeup if you have one. I will say that you only have multiple proposers if the proposers cannot talk to one another, as otherwise they would be silenced by any simple leader election protocol (heartbeats + node rank, etc.) It's true that the leader election protocol is not part of paxos per se but all implementations will have…
Comment linking /papers-and-talks/distributed-consensus-paxos-raft-etc/
on “The Paxos Algorithm, or How to Win a Turing Award”Submitted Von Neumann’s critique of automata theory and logic in computer science (1947) as a story · 141 points
HN discussionI wrote a little simulation. Paxos rarely gets stuck with a small number of proposers/acceptors, but jams up solid once you get to, I forget, 10 or 20. Here it is: https://www.yodaiken.com/wp-content/uploads/2016/10/paxos.pt... Embarrassingly badly written Lua code for the simulator https://github.com/yodaikenv/consensus The key to me is that once you accept the need for leader election, you have much simpler altern…
Comment linking /wp-content/uploads/2016/10/paxos.ptpx_.ppxt_.png
on “The Paxos Algorithm, or How to Win a Turing Award”Submitted Three proposals for the C standard WG14 as a story · 72 points
HN discussionReminds me of strict aliasing. Same attitude... https://www.yodaiken.com/2018/06/07/torvalds-on-aliasing/
Comment linking /2018/06/07/torvalds-on-aliasing/
on “GCC 15.1”Submitted Dennis Ritchie on alias analysis in C (1988) as a story · 62 points
HN discussionThe standard massively conflicts with the practices used in existing C programs by existing C programmers. Yes, it's perfectly possible to write code that doesn't violate any of the (largely implicit, it's worth noting) strict-aliasing rules. But was it a good idea for the standard to allow optimizing compilers to silently break massive amounts of existing code that has worked for years? Even if that were acceptable…
Comment linking /2018/05/20/depressing-and-faintly-terrifying-days-for-the-c-standard/
on “Torvalds: Standards need to be questioned”Submitted PLOS2021: ISO-C became unusable for operating systems as a story · 57 points
HN discussionDirect link to PDF: http://www.yodaiken.com/wp-content/uploads/2018/05/ub-1.pdf
Comment linking /wp-content/uploads/2018/05/ub-1.pdf
on “Depressing and faintly terrifying days for the C standard [pdf]”Submitted On C-optimizing compilers removing code that has undefined behavior as a story · 40 points
HN discussionhttps://www.yodaiken.com/2021/05/21/your-computer-is-a-fast-...
Comment linking /2021/05/21/your-computer-is-a-fast-pdp-11-and-more-on-c-the-c-standard-and-computer-architecture/
on “Undefined behavior in C is a reading error”Submitted Synchronous Processors (2016) as a story · 30 points
HN discussionFYI https://www.yodaiken.com/2021/05/21/your-computer-is-a-fast-...
Comment linking /2021/05/21/your-computer-is-a-fast-pdp-11-and-more-on-c-the-c-standard-and-computer-architecture/
on “Undefined behavior in C is a reading error”Submitted Possibly Fun C Code as a story · 29 points
HN discussionRunning Linux under something lower level is old hat, see RTLinux: http://www.yodaiken.com/papers/BarabanovThesis.pdf [1997] Well, that's not exactly a microkernel, but took lots of inspiration from microkernels. I take it that you may be alluding to the debate between Torvalds and Tannenbaum regarding microkernels. https://en.wikipedia.org/wiki/Tanenbaum%E2%80%93Torvalds_deb...
Comment linking /papers/BarabanovThesis.pdf
on “HelenOS: portable microkernel-based multiserver operating system”Submitted The fault-tolerant Auragen file system from pre-history as a story · 29 points
HN discussion[Edit: this isn't true] That is definitely how it is used, and it works on the major compilers. But, surprisingly, this is indeed undefined behaviour according to the standard. There was an infamous rant by Linus [1] (more infamous for the language than the subject) about how the kernel can and should continue to use unions for type punning. He noted that even though the C standard doesn't specify a behaviour for th…
Comment linking /2018/06/07/torvalds-on-aliasing/
on “How Safe Is Zig?”Submitted Undefined behavior in C is a reading error (2021) as a story · 25 points
HN discussionType punning/aliasing with unions is well defined in gcc. Linus even has a humorous rant about it on the topic: https://www.yodaiken.com/2018/06/07/torvalds-on-aliasing/ Sure, it's compiler-specific, but I'm already using `__attribute__((packed))` anyways.
Comment linking /2018/06/07/torvalds-on-aliasing/
on “Learning that you can use unions in C for grouping things into namespaces”Submitted C Standard Undefined Behavior vs. Wittgenstein [pdf] as a story · 16 points
HN discussionJust a reminder that there are ZERO published studies showing that these UB "optimizations" have significant value for any real programs. They impose a bizarre notion of C semantics that is not compatible with the language design. A good critique, for example, of the UB alias behavior can be found in Brian Kernhighans article on Pascal ( http://www.cs.virginia.edu/~evans/cs655-S00/readings/bwk-on-... ). The Standard…
Comment linking /2018/11/17/standard-c-is-more-fun-than-ordinary-c/
on “Undefined Behavior Is Really Undefined”Submitted Undefined behavior in C is a reading error as a story · 9 points
HN discussionSome of those are classics. The Lipton-Perlis-DeMillo argument against program verification is a good one.[1] They demonstrated that manual programming verification via hand theorem proving is buggy. Automated theorem proving was new back then. This was an issue back in the 80s for a philosophical reason in mathematics. Mathematics classically approves of short, clever, elegant proofs. The paper-and-pencil crowd was…
Comment linking /papers/p271-de_millo.pdf
on “Vigorous Public Debates in Academic Computer Science”Submitted Understanding Paxos as a story · 8 points
HN discussion
