1. Thread: Tech we can’t use or teach?
Total comment counts : 20
Summary
The author of the article discusses their experience with a failed project and their frustration with the reasons behind the failure. They talk about their previous project, an over-engineered coffee bean storage and inventory system, and how it inspired others to start similar projects. They then discuss their current projects, one of which is a new version of the coffee storage display aimed at increasing the battery runtime. The author explores low-power electronics and discovers that WiFi is inefficient for their project. They consider alternatives such as LoRa and Zigbee, but settle on Thread as an interesting option due to its use of the IPv6 protocol and its compatibility with existing devices like Apple HomePod and Nest Hub. The author highlights the advantages of Thread’s mesh network and the availability of Thread Border Routers. They also mention the use of Thread repeaters to extend the network’s reach.
Top 1 Comment Summary
The city decided to use LoRawan because it is less complicated legally, despite being more complicated to work with. However, Danish telecom laws restrict the use of such technology and give telecom companies a monopoly on high-speed internet. This also applies to threads. The advantage of using LoRawan in a city is that there are many locations to set up antennas, such as public schools and libraries, which the public does not have access to. The key is to persuade the city to make their LoRawan equivalent open to the public if you want to deploy devices throughout the city. Additionally, the city may provide free access to power supplies and financial support for projects that benefit the city. Ultimately, the advice is to avoid using threads.
Top 2 Comment Summary
The article states that if you are a hobbyist without a lot of money, you cannot legally use Thread, a networking protocol. The author questions if this is really true, suggesting that patents may only apply if there is commercial activity involved. The article further asserts that the current patent regime grants monopolies, as big companies can freely use OpenThread, while small businesses and startups cannot. Overall, the article presents this situation as unfair and suggests that it has a chilling effect.
2. The derivative of a number (2014)
Total comment counts : 14
Summary
The article discusses Edward Barbeau, a professor emeritus of mathematics at the University of Toronto, who has worked on increasing interest in mathematics and enhancing education. One of Barbeau’s contributions is his definition of the derivative of a number. While the concept of a derivative is commonly understood for functions, Barbeau extends it to natural numbers using specific rules. Despite its interesting nature, Barbeau’s derivative of a number has not been extensively studied. However, there have been recent papers exploring its intrinsic properties, solutions to differential equations, growth and inequality results, and potential extensions beyond natural numbers. The article also mentions an attempt to use Barbeau’s derivative to prove something unrelated to numbers. Overall, the derivative of a number remains an intriguing concept that may have untapped potential.
Top 1 Comment Summary
The article explains that mathematicians often use the same name for two things with the same “structure,” even if they may not seem related. In this case, the shared structure is that both the derivative of a function and D(n) follow the product rule of derivatives. The article goes on to describe how a morphism can be constructed by finding functions for each prime number that have a specific value and derivative. These functions can then be multiplied together for all other natural numbers. The resulting function is called F_n(x), and it involves the prime factors of n. The article concludes by stating that there is a homomorphism between D and the derivatives of functions, which suggests that D is indeed a derivative.
Top 2 Comment Summary
The article discusses the concept of the Derivative of Regular Expression and its practical uses. It refers to the link mentioned for more information.
3. Why the CORDIC algorithm lives rent-free in my head
Total comment counts : 11
Summary
The article discusses the CORDIC algorithm, which allows for computing trigonometric functions on low-powered hardware without floating point operations or expensive lookup tables. The algorithm uses simple additions and bit shifts to perform complex calculations by combining vector math, trigonometry, convergence proofs, and computer science. The article explains that this algorithm is particularly useful for embedded environments and less capable microcontrollers and FPGAs. It also discusses how fixed-point representation can be used instead of floating point to represent rational numbers, and explains the basic operations such as addition, subtraction, multiplication, and division in fixed-point arithmetic. Finally, the article introduces CORDIC as a solution for more complex functions like trigonometric functions.
Top 1 Comment Summary
The article discusses Meagher’s octree system, which utilizes efficient algorithms for various operations such as Boolean operations, geometric operations, N-dimensional interference detection, and display. These algorithms do not require floating-point operations, integer multiplications, or integer divisions. This system has allowed for the development of quick and customized VLSI graphics acceleration hardware for octree representation.
Top 2 Comment Summary
The author discusses the challenge of achieving deterministic floating-point calculations across different platforms, especially in applications like FPGA and game development. One solution is to use a fixed-point physics engine instead of floats, which would require implementing trigonometric functionality using CORDIC. The author started working on this as a side project but has yet to finish it.
4. So We’ve Got a Memory Leak
Total comment counts : 9
Summary
The article discusses the experience of dealing with a memory leak in a decade-old Rails app. The author explores various tools and techniques for identifying and fixing memory leaks, including profiling memory allocations, generating heap dumps, and analyzing code changes. Despite reviewing recent code changes and making tooling adjustments, the memory leak persisted. The author noticed that the leak occurred only in web Dynos and not in Sidekiq and Delayed::Job Dynos, leading to suspicion that it may be specific to certain types of traffic. The article concludes by mentioning the inability to use OpenTelemetry Traces to pinpoint the cause of the leak due to aggressive sampling.
Top 1 Comment Summary
The author of the article does not understand the fear associated with manual memory management. They argue that with proper engineering practices, such as Resource Acquisition Is Initialization (RAII) and clear ownership rules, managing memory becomes easy. They find it more challenging to deal with frameworks that use reference counting and shared pointers because ownership becomes unclear. The author believes that memory bugs are no worse than logic bugs and should be fixed as part of engineering discipline. They also point out that they manually manage other resources like operating system handles and sockets, so they question the need for automatic memory management, which they see as complicating the design.
Top 2 Comment Summary
The author recalls a story from the 90s about a memory leak in a printer driver in Solaris. They worked for a bank that relied on faxes to confirm trades, and when the memory leak caused a confirmation to not be printed, it resulted in a $5 million loss. Despite senior executives’ efforts, the bank was unable to resolve the issue and made a policy to never trade with that particular bank again. The fax printer job was eventually moved to Windows NT. The article also mentions that the memory leak was eventually fixed because Scott McNealy, the CEO of Sun Microsystems at the time, experienced the problem firsthand and pushed for a solution.
5. One Minute Park
Total comment counts : 16
Summary
The One Minute Park project allows users to view one-minute videos of parks from around the world. The goal of the project is to have a video for every minute of the day. The project is created by Elliott Cost and relies on support for funding. Users can help by creating their own One Minute Park or supporting the project through donations or sponsorship.
Top 1 Comment Summary
I apologize, but you have not provided an article for me to summarize. Could you please provide the article so that I can assist you?
Top 2 Comment Summary
The author of the article states that they feel more engaged with a video when the sound is turned off. They explain that with the sound on, the experience feels similar to watching any other video online and the audio quality from the microphone doesn’t capture the true feeling of being present. On the other hand, when the sound is off, they find a greater sense of tranquility and a stronger connection to the visuals, as they blend with the actual sounds of their surroundings.
6. Unix and Multics (2019)
Total comment counts : 5
Summary
This article provides a brief history of Unix and its development. It starts by mentioning the Multics project in 1964, where Bell Telephone Laboratories (BTL) collaborated with MIT and General Electric. The article discusses the contribution of various programmers, including Ken Thompson and Dennis Ritchie, and their work on the Multics project. It also mentions Bell Labs’ impatience with the slow progress of Multics and their decision to withdraw from the project in 1969. The article then highlights the emergence of Unix and its joke name, coined by Brian Kernighan, as a reference to Multics. It mentions a conference in 1973 where Ken and Dennis presented Unix, and the paper they presented won the best paper award. The article concludes by mentioning the author’s personal involvement in promoting Unix at MIT and a conversation with Dennis Ritchie about error recovery code. The author also mentions giving a speech at a conference in Paris in 1978.
Top 1 Comment Summary
The article discusses a conversation between two individuals regarding writing error recovery code in a system called Multics. One person mentions that a significant portion of their coding involved error recovery, while the other person reveals that in their system, error recovery is handled by a routine called panic(), which causes the machine to crash, requiring a reboot. This approach is referred to as the “New Jersey Style.”
Top 2 Comment Summary
The article discusses the Department of Defense’s security assessment of Multics and highlights the advantages of PL/I over C in terms of memory safety.
7. Show HN: Wag, MFA and Enrollment for WireGuard
Total comment counts : 6
Summary
The article discusses the key features of a tool called Wag, which adds multi-factor authentication (MFA), route restriction, and device enrollment to WireGuard. Some of the important details mentioned include the requirement of having iptables and libpam installed, running Wag as root, enabling forwarding in sysctl, and needing a kernel newer than 5.9+.
The article also mentions various commands that can be used with Wag, such as starting the server, cleaning up, reloading ACLs, and managing devices and users. It explains the process of generating a token, authenticating users through their 2fa code, and setting the configuration file.
Other topics covered include trusted reverse proxies, email address configuration, lockout settings, NAT (masquerading) options, exposing ports on the VPN server, checking for updates, customizing MFA templates, downloading the WireGuard config file, and various configuration options related to session lifetime, inactivity timeout, database location, socket, access control lists (ACLs), policies, web server addresses, and authentication methods.
The article concludes by mentioning specific configuration options for OIDC (OpenID Connect), such as the issuer URL.
Overall, the article provides a detailed overview of the features, requirements, and configurations of the Wag tool for enhancing the security and management of WireGuard.
Top 1 Comment Summary
The article discusses various aspects of a registration process for a server, as well as the need to update the example provided to use a secure protocol instead of HTTP. The author also discusses the authentication process and suggests the idea of implementing a wireguard client with captive portal detection functionality. However, the author mentions that they have not found such a client yet.
Top 2 Comment Summary
The article discusses the importance of session management in wireguard key implementation. It suggests that software that implements wireguard transport layer should have session management capabilities to be considered a fully functional VPN server solution. This includes features like rotating session keys, terminating sessions, changing IP addresses, configuring new routes, and repeating authentication when needed.
8. Pyramid3D Real-time Graphics Processor (1997) [pdf]
Total comment counts : 7
Summary
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Top 1 Comment Summary
The article discusses the availability of relatively inexpensive graphics cards in the late 1990s. The author mentions owning cards from Matrox, Dynamic Pictures, and a Fujitsu prototype. These “pro” cards were eventually replaced by gamer cards, which made GPUs more accessible to the general public. The article also mentions that SGI, a computer hardware company, also faced challenges due to this shift in the market. The Oxygen 102 card from Dynamic Pictures, for example, was initially priced at $1495 in 1996 but later reduced to $399.
Top 2 Comment Summary
The article discusses the connection between the PC demoscene and the development of hardware, specifically a processor related to Future Crew. The author mentions that the article is a bit disjointed but provides helpful information.
9. Show HN: Jacinda, a functional Awk (text stream processing on the comamnd-line)
Total comment counts : 5
Summary
The article discusses a command-line tool called Jacinda, which is a functional pattern sifting language similar to AWK. It is powered by Rust’s regex library and is designed to simplify cross-compiling. The article provides instructions on installing Jacinda and dependencies on different platforms. It also mentions the availability of plugins for text editors like Vim and VSCode. The tool uses regular expressions to match relevant lines and extract data. The article suggests referring to the guide and manpages for more information and examples. It also mentions that the tool is missing some features and welcomes bug reports and contributions.
Top 1 Comment Summary
The article discusses the use of the colon in various contexts and provides examples to help explain its functionality. It explains how the colon is used for type conversion and discusses the cases where it is used without anything on its left-hand side. It also highlights the difference between [: and : as separate operators.
Top 2 Comment Summary
The author is discussing the advantages and disadvantages of using awk, specifically focusing on its functional aspects. They provide several examples of how they use awk in a functional manner, such as filtering, folding, mapping, and concatenating operations. However, they also mention features of awk that are less functional, such as mutation and lack of compositionality. They compare this to the “functional” programming language jq, which allows for composition of programs. The author wonders if there is a way to achieve composition of awk programs without resorting to using byte streams.
10. The Foundation of a Generic Theorem Prover (1989) [pdf]
Total comment counts : 4
Summary
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Top 1 Comment Summary
The article is a good resource for understanding the basics of Isabelle, but it mentions that additional literature for a complete understanding of Isabelle is scattered across multiple papers.
Top 2 Comment Summary
The article provides a link to information about designing a theorem prover in the field of computer science, as well as a chapter from a book called “ML for the Working Programmer” that discusses this topic.