2019-04-27

2018-04-07

2019-05-26

I hate telephones. Some rational reasons: lack of authentication, no spam filtering, forced synchronous communication. But also just a visceral fear. 2017-11-08

2014-05-11

Hacker News buried my post on conspiracy theories in my family due to overheated discussion, not censorship. Moderation keeps the site focused on interesting technical content. 2019-01-26

2019-01-20

Try setting the root font-size to calc(1rem + 0.25vw) instead of using media queries with fixed breakpoints. 2024-03-12

2020-02-09

Trick Android to display an SMS as coming from any contact. Convincing phishing vuln, but still unpatched. 2020-08-06

A “true or false” quiz where you respond with your confidence level, and the optimal strategy is to report your true belief. 2020-04-26

2020-03-14

I got started with simple web development, but because enamored with increasingly esoteric programming concepts, leading to a “trough of hipster technologies” before returning to more productive work. 2019-03-23

Bob invents asymmetric cryptography by playing loud white noise to obscure Alice’s message, which he can cancel out but an eavesdropper cannot. This idea, published in 1944 by Walter Koenig Jr., is the forgotten origin of asymmetric crypto. 2019-02-16

OpenSSL’s inadequate documentation, confusing key formats, and deprecated interfaces make it difficult to use, despite its importance. 2017-12-02

2017-10-26

Granddad died. The unspoken practice of death-by-dehydration in the NHS. The Liverpool Care Pathway. Assisted dying in the UK. The importance of planning in end-of-life care. 2017-05-19

2017-02-17

2024-03-20

2024-03-14

Errors in JavaScript cause an ErrorEvent on window. Preventing the default action blocks console output. Resource errors follow the capture-bubble event model. 2024-03-13

Try setting the root font-size to calc(1rem + 0.25vw) instead of using media queries with fixed breakpoints. 2024-03-12

2024-03-11

2024-03-09

The “golden rule” of code reviews is to approve improvements. Approve pull requests that fix bugs, even if the implementation isn’t ideal. 2023-10-07

A workshop to show the importance of estimation, and teach self-calibration using facts about your company. 2023-09-13

2023-09-04

A primary feature of a collaborative product is its social norms. I look at LessWrong, a forum product, and show how it builds its social norms. 2023-08-28

2023-06-14

2022-12-14

2022-11-02

2022-10-17

2022-10-13

2022-09-10

2022-09-08

2022-07-15

2022-02-24

2022-02-09

2022-01-17

2021-03-09

2021-02-17

2021-02-16

2021-02-15

2021-01-19

2021-01-18

Screen recording accidentally encoded superwhite/superblack due to obsolete yuv420p(tv) color space; rescaling fixes it. 2021-01-13

How to create an NPM addon package from C++ code using the node-gyp tool and a binding.gyp file, with a JavaScript wrapper module for a more idiomatic API. 2020-12-07

I implement homogeneous coordinates in 3D, including rotation, scaling, translation, and projection matrices, and use them to create an animated 3D house scene. 2020-11-29

Homogeneous coordinates enable a matrix to translate points. I show a six-line JS library. 2020-11-28

A 5-line matrix library, and how to derive it without rote memorization. 2020-11-27

2020-11-03

JavaScript has two different “prototype” concepts: an own property with the string key “prototype”, and a parent slot. Don’t confuse the two! 2020-11-02

2020-11-01

A playground to explore the various widths and heights of a <video> element, as reported by different browser APIs, when displaying a webcam stream with dynamically adjustable constraints. 2020-10-23

WebGL’s texImage2D function expects pixels in bottom-to-top order, while browsers provide them top-to-bottom. UNPACK_FLIP_Y_WEBGL fixes this behavior. 2020-10-22

2020-10-21

2020-10-19

The MediaStream Recording API converts a MediaStream to a Blob of compressed video and audio. A demo where you can record a 5-second clip. 2020-10-17

2020-10-16

2020-10-15

2020-10-14

A WebRTC-based group chat application that uses Ably’s publish-subscribe system for signaling. Clients connect directly via peer-to-peer data channels, with Ably facilitating the initial connection. 2020-10-13

A method for calculating a bounding circle around a head, using facial landmarks from BlazeFace. Plus a live demo that you can run on your own face. 2020-10-12

A method for calculating a bounding circle around a head, using facial landmarks from BlazeFace. Plus a live demo that you can run on your own face. 2020-10-11

Involves downloading the model manifest file and associated binary weight files, to avoid downloading large models every application launch. 2020-10-07

2020-10-06

Node.js REPL uses the inspector module to safely evaluate expressions as you type, using V8’s evaluation with throwOnSideEffect: true to avoid executing harmful code. 2020-10-05

2020-10-04

2020-10-03

2020-10-02

2020-10-01

NPM is Node.js’s package system, allowing installation of arbitrary stuff, not just Node.js modules. Packages are folders, tarballs, URLs, or version identifiers published to the NPM registry. 2020-09-30

2020-09-29

ES modules are just concatenated source files, with some error checking and variable renaming. Live bindings are an illusion - they’re just ordinary variables at the top-level scope. 2020-09-28

The require function in Node.js loads modules, either local files or external packages. I show the algorithm that searches node_modules directories and package.json files. 2020-09-27

Source maps map generated JavaScript to original source files, allowing debugging of the original code in the browser’s dev tools. 2020-09-26

JavaScript modules enable better dependency management and scoping. A guide for developers like me who still use <script> tags everywhere. 2020-09-25

2020-09-24

2020-09-23

2020-09-22

2020-09-21

2020-09-20

2020-08-31

BodyPix is a TensorFlow model for person segmentation. A demo of BodyPix in the browser. 2020-08-16

WebGL alpha-transparency may appear wrong because of premultiplied alpha. Fix it by setting premultipliedAlpha: false when creating the WebGL context. 2020-08-12

A green screen implementation in the browser using WebGL and chroma key. Includes a live demo. 2020-08-11

2020-08-10

2020-08-09

Trick Android to display an SMS as coming from any contact. Convincing phishing vuln, but still unpatched. 2020-08-06

2020-08-03

2020-07-31

Calling setFrameAutosaveName on an NSWindow causes its size and position to be saved to user defaults, overriding the contentRect passed to the constructor. To avoid this, do not call setFrameAutosaveName. 2020-07-10

A “true or false” quiz where you respond with your confidence level, and the optimal strategy is to report your true belief. 2020-04-26

2020-04-24

2020-03-14

2020-03-13

2020-03-12

Implementing Conway’s Game of Life in WebGPU, a 2D cellular automaton simulation. Uses compute shaders to update the game state and render the cells. 2020-03-03

A WebGPU-powered simulation of the Rule 110 cellular automaton, rendering a dynamic image on a canvas. 2020-03-02

I write an ArrayBuffer to a canvas by interpreting the buffer as pixel data and using ImageData to provide the dimensions. 2020-03-01

Blurring sensitive information in images may not effectively protect privacy, as the original content can often be recovered using deblurring techniques. 2020-02-29

2020-02-23

RNA genomes of viruses like COVID-19 are often sequenced as complementary DNA (cDNA) for practical reasons, though the actual genome is made of RNA with uracil instead of thymine. 2020-02-16

2020-02-15

2020-02-09

An algorithm in Haskell using a breadth-first search to find the reachable set of nodes. 2020-01-24

An O(n) algorithm to check if a binary tree is balanced, by passing up the height from recursive calls. 2020-01-23

2020-01-22

2020-01-21

2020-01-20

2020-01-19

2020-01-18

2020-01-17

2020-01-16

A trick to find the middle of a linked list by using two pointers, slow and fast, where fast moves twice as fast as slow. 2020-01-15

Reverse a linked list by treating it as a stack, popping elements and pushing them onto a new list. An implementation in C without a separate stack. 2020-01-14

A C function to partition a linked list around a value x, running in optimal time and space. 2020-01-13

2020-01-12

2020-01-11

2020-01-10

An in-place algorithm to rotate a square matrix by 90 degrees. The key is to rotate 4 corresponding points using a formula, applying this to all points in the top-left corner. 2020-01-09

2020-01-08

A C function to replacing spaces with "%20" in-place, by iterating from the end, preserving true string length. 2020-01-07

A C function to determine if one string is a permutation of another, using a character distribution representation for optimal time and space complexity. 2020-01-06

2020-01-05

A recursive algorithm to determine if a string has all unique characters, with an analysis of its time complexity. 2020-01-04

2020-01-01

Exploring my 23andMe genome data - a text file of single nucleotide polymorphisms, not a full DNA sequence, requiring a reference genome to interpret. 2019-12-30

2019-12-29

2019-12-28

CSS variables, also called custom properties, allow defining and using dynamic values in CSS. They cascade and inherit like other CSS properties, with the var() function used to reference them. 2019-12-21

Startups must get the foundations right from the start. Choose co-founders carefully, keep the board small, hire full-time employees, and compensate with equity over high salaries, even for the CEO. 2019-10-07

2019-10-06

2019-05-28

A mathematical model where the neuron is a function that takes binary inputs and produces a binary output based on a threshold. The model can implement basic logic gates like AND and OR, but not more complex functions like XOR. 2019-05-27

2019-05-26

Generators in JavaScript can act as both producers and consumers of data. An example Metric generator batches and sends data using the yield keyword. 2019-05-18

2019-05-17

Symbols are a new fundamental data type in JavaScript, introduced in 2015. They are used to create unique object property keys that won’t clash with other properties. 2019-05-16

2019-05-15

2019-05-10

2019-05-06

2019-05-05

2019-05-04

2019-04-27

I create a native Node.js addon called addon in C++ using node-gyp. The addon exports a hello() function. 2019-04-20

Installing Electron, creating an HTML web page, and writing the main entry point script to load the page. 2019-04-19

Cycling tour of France’s Loire Valley, visiting chateaux, wineries, and medieval attractions over 5 days, from Tours to Nantes. 2019-04-09

2019-04-02

2019-04-01

Betting exchanges like Betfair allow users to act as bookmakers, offering bets at their own chosen odds. This contrasts with traditional bookmakers who set the odds. 2019-03-31

Different notations for betting odds, including fractional, decimal, and probability. Probability notation is shown to be the most transparent, revealing the bookmaker’s expected positive gain. 2019-03-30

I got started with simple web development, but because enamored with increasingly esoteric programming concepts, leading to a “trough of hipster technologies” before returning to more productive work. 2019-03-23

CSS visited link styles are limited for security reasons, as they could reveal a user’s browsing history. Color can be changed, but getComputedStyle will lie about it. 2019-03-08

Bob invents asymmetric cryptography by playing loud white noise to obscure Alice’s message, which he can cancel out but an eavesdropper cannot. This idea, published in 1944 by Walter Koenig Jr., is the forgotten origin of asymmetric crypto. 2019-02-16

2019-01-27

Hacker News buried my post on conspiracy theories in my family due to overheated discussion, not censorship. Moderation keeps the site focused on interesting technical content. 2019-01-26

2019-01-20

Jekyll build breaks due to Bundler 2 incompatibility. Fixed by removing Bundler 1 version from Gemfile.lock. 2019-01-09

Redis Sentinel provides high availability for Redis. We start a Redis master, then three Redis Sentinel instances. They discover each other, then we trigger a failover. 2019-01-08

Use nc (netcat) to create a web server that returns custom HTTP responses. 2018-12-31

I use a custom blogpost command to quickly create new blog post files with the current date and post title. 2018-12-30

I demonstrate animating a cat walk cycle on an HTML canvas using a sprite sheet image and the drawImage method. 2018-12-29

2018-12-28

Cookies are client-side storage that get sent with every HTTP request. A cookie is scoped to a domain suffix, a path prefix, and a time range. The API is old and weird. 2018-12-22

A visualization of how frequently different years are referenced in writing over time, showing patterns in how the past and future are viewed. 2018-12-18

2018-12-17

2018-11-25

2018-11-15

How to use the undocumented Strava Route Builder API to get routes between two points, including a JavaScript example. 2018-10-13

2018-09-23

The USA believes in the future is unpredictable but will get better. A false contradiction. Success is not random, as evidenced by serial entrepreneurs who have founded multiple billion-dollar businesses. 2018-09-19

2018-09-17

2018-09-16

Profitable companies are monopolies, not competitors. Competition drives down prices but also wages and quality. Monopolies are not permanent, as new markets and products can create new monopolies. 2018-09-15

2018-09-14

2018-09-13

2018-07-29

Redis sorted sets are implemented using a hash table for efficient key-value lookups and a skip list for efficient score-based ordering. I show a Haskell implementation that uses a forward map for keys and a reverse map for scores. 2018-04-22

2018-04-07

2018-04-01

/dev/stdin, /dev/stdout, and /dev/stderr are special files in the /dev directory that represent the standard input, output, and error streams of a process. They can be used to connect processes in a shell pipeline without creating temporary files. 2018-03-31

An efficient algorithm to round up to the next power of two in C, using bitwise operations and compiler intrinsics for constant-time performance. 2018-03-30

2018-03-27

Creating and using an SSH certificate authority, an alternative to the default “trust on first use” model. 2018-03-16

A lambda calculus interpreter in Haskell, using de Bruijn indexing and lazy evaluation, with simple integer literals added. 2018-03-15

2018-03-10

I write a parser for JimScript, an imperative programming language, in Haskell. The parser goes through three stages: tokenization, nesting, and parsing. 2018-03-09

2018-03-06

2018-03-04

2018-03-02

Linux uses exponential backoff to retry dropped TCP connections, with a configurable retry limit. 2018-02-27

2018-02-24

2018-02-23

The magic shell string 3>&2 2>&1 1>&3- swaps stdout and stderr. It does with the dup2 system call to swap file descriptors. 2018-02-22

2018-02-20

2018-02-19

2018-02-17

2018-02-12

IP addresses are mapped to MAC addresses using the Address Resolution Protocol (ARP). The OS maintains an ARP cache to store these mappings. 2018-02-11

Subnets divide the IP address space hierarchically using bitstring prefixes. We check if an IP address is in a subnet using C. 2018-02-10

2018-02-09

A C implementation of run-length encoding, a compression scheme that works well on inputs with consecutive repeated characters. 2018-02-08

2018-02-07

DHCP dynamically assigns IP addresses to hosts, using a client-server protocol over UDP. It involves a sequence of DORA (Discover, Offer, Request, Acknowledge) messages to obtain and configure a network lease. 2018-02-06

nscd, a local DNS resolver within glibc, is non-standard. Instead, use a local DNS server like named or dnscache. 2018-02-05

2018-02-03

tcpdump captures and displays network traffic. An example inspecting DNS requests and responses. 2018-02-01

2018-01-23

2018-01-21

I propose BootstrapCC, a project to build a C compiler from a tiny handwritten program, avoiding the trust problem in Thompson’s “Reflections on Trusting Trust”. 2018-01-11

2018-01-10

Methods for hashing multiple values, including hash-then-XOR, concat-then-hash, and serialize-then-hash. The only method that’s collision-resistant is serialize-then-hash! 2018-01-09

A stream cipher in Go that generates an infinite keystream from a shared key using SHA-256. 2018-01-01

2017-12-11

An open addressing hash table implementation in C, which resolves collisions by finding alternative buckets for elements using linear probing. 2017-12-10

2017-12-09

Modular arithmetic involves operations like addition, subtraction, multiplication, and exponentiation that “wrap around” a fixed modulus. This is useful for cryptography like RSA. 2017-12-08

Inline quizzes make reading more engaging by requiring readers to participate in the content. 2017-12-07

2017-12-06

Creating a Facebook Messenger bot for a Christmas game ‘Nativité’, switching from expensive SMS notifications. The bot is hosted on Heroku and Netlify, with Pusher for real-time updates. 2017-12-05

2017-12-04

2017-12-03

OpenSSL’s inadequate documentation, confusing key formats, and deprecated interfaces make it difficult to use, despite its importance. 2017-12-02

ASN.1 is a data format used to encode structured data like RSA private keys and certificate signing requests. Using openssl asn1parse to reveal its structure. 2017-11-30

The used metric in free -m includes memory used for caching, not just application memory. The true memory usage is lower, calculated as used minus buffers/cache. 2017-11-29

GitHub-Flavored Markdown supports “diff views” with + and - prefixes. While it loses syntax highlighting, it’s a quick and easy way to show changes. 2017-11-27

2017-11-26

DNS resolution is a recursive procedure involving different record types like A, CNAME, and NS. Resolving a domain name can require multiple DNS queries to different nameservers. 2017-11-25

I start using tags to categorize blog posts, enabling audience-specific features like subreddit auto-posting, customizable RSS feeds, and push notifications. 2017-11-24

A proposal to use “diff views” in technical writing to clearly differentiate code under discussion from contextual information, similar to the format of version control diffs. 2017-11-23

The @NSApplicationMain annotation in Swift automatically sets up the application’s entry point, including creating the NSApplication instance and assigning the AppDelegate class. 2017-11-13

Replaced static image on this site with a looped video. Experimenting with subtle motion to mimic images at first glance. 2017-11-12

Cost-based pricing sets prices to cover costs plus profit, while value-based pricing sets prices based on customer willingness to pay. The optimal SaaS pricing model uses value-based inputs like user count that approximate customer value. 2017-11-11

2017-11-10

2017-11-09

I hate telephones. Some rational reasons: lack of authentication, no spam filtering, forced synchronous communication. But also just a visceral fear. 2017-11-08

2017-11-07

2017-11-06

Promises in JavaScript represent future values. They provide a way to handle asynchronous operations, allowing chaining of callbacks. Promises can be fulfilled or rejected, with callbacks handling each case. 2017-11-05

2017-11-04

Generating ECDH keys and deriving a shared AES key. 2017-11-03

Generating a key, encrypting and decrypting text, and explaining the implementation. 2017-11-02

2017-10-31

2017-10-30

2017-10-29

A WebGL shader that combines diffuse and specular lighting, allowing the user to adjust the relative contribution of each using keyboard controls. Guest post by Luís Fonseca. 2017-10-28

2017-10-27

2017-10-26

2017-10-25

Differences between the Web Push API in Google Chrome and Firefox. Firefox uses the Mozilla Push Service, enabling push notifications without Google’s GCM/FCM. 2017-10-24

Implements a 1024x1024 grid of Conway’s Game of Life using WebGL fragment shaders. 2017-10-23

A Conway’s Game of Life simulation implemented using WebGL fragment shaders, with rendering to texture and a Gosper Glider Gun initial state. 2017-10-22

Rendering an animated 3D cube in WebGL using a vertex shader, face color uniforms, and matrix transformations for rotating the cube. 2017-10-21

Generating dynamic normal-mapped ripple effects using WebGL, with the mouse position controlling the light source. 2017-10-20

GLSL varying allows vertex shader outputs to be passed to fragment shaders. A WebGL demo with colors interpolated between vertices. 2017-10-19

2017-10-18

Combining two textures in a WebGL fragment shader, using texture units and uniform locations to access the textures. 2017-10-17

2017-10-16

Random slopes are interpolated to create a smooth, wiggly line. More realistic noise is achieved by combining multiple octaves. 2017-10-15

A program to create a cyan window on macOS using C and the GLFW library. 2017-10-14

2017-10-13

Contrasting diffuse and specular shading models in WebGL, with live demos showing matte vs. shiny surface renderings. 2017-10-12

2017-10-11

2017-10-10

A WebGL visualization of a point in 4D homogeneous clip space. Explore the effects of the x, y, z, and w components. 2017-10-09

WebGL has several spaces that need to be properly managed to display content correctly. 2017-10-08

2017-10-07

Using WebGL to load an image and swap its RGB channels with a fragment shader. 2017-10-06

2017-10-05

A WebGL demo that creates a 2x2 checkerboard texture, uploads it to the graphics driver, and samples from it in the fragment shader to display a blurred checkerboard pattern. 2017-10-04

Shader uniforms in WebGL are global variables that allow passing data from the JavaScript application to the shader. A demo shows how to update a uniform representing the mouse position and use it to generate a dynamic pattern. 2017-10-03

2017-10-02

2017-09-30

2017-09-29

Lack of a standard Unicode feed icon despite its widespread use. I plan to submit a proposal for its inclusion. 2017-09-28

2017-09-27

How to create an IndexedDB database, add an object store, and read/write data. 2017-09-26

2017-09-25

2017-09-24

Browsers offer various storage options, including cookies, localStorage, sessionStorage, IndexedDB, CacheStorage, WebSQL, and AppCache, each with its own tradeoffs in terms of use case, persistence, and support. 2017-09-23

Adding an RSS feed to a Jekyll blog using the jekyll-feed gem, configuring _config.yml, and adding links to the HTML template. 2017-09-22

Browser generates keys, shares public key; server encrypts data with it; browser decrypts push payload. 2017-09-21

notificationclick service worker event lets the web app open a webpage via clients.openWindow. 2017-09-20

Web applications can “subscribe” for notifications via PushSubscription endpoint, but there’s poor interoperability between different browsers’ push services. 2017-09-19

2017-09-19

An efficient way to represent and sample from a discrete probability distribution, using a balanced binary tree data structure called the “urn”. 2017-09-18

I install Rust, create a “Hello World” program, and compare it to the equivalent C program. The Rust binary has additional dependencies beyond the standard C library. 2017-09-17

2017-09-16

2017-09-15

2017-09-14

The Background Sync API lets service workers execute tasks even when the client page is not active. It queues jobs that run as sync events, which can trigger desktop notifications. 2017-09-13

Deprecated new Notification() replaced with ServiceWorkerRegistration.showNotification(). 2017-09-12

2017-09-11

Service workers are scripts that run outside the browser context, allowing web apps to perform tasks like caching, network requests, and offline functionality. 2017-09-10

2017-09-09

Using a service worker to monitor the sitemap and display updates via browser notifications. 2017-09-08

The web Notification API allows web apps to display system-level notifications, requiring user permission. It has two key parts: requesting permission and creating notifications. 2017-09-07

Paginate an API with either array indexing (?page_number=) or dictionary indexing (?first_word=). Array indexing suffers from shifting page boundaries, but is easier to parallelize. Dictionary indexing requires ordering, but handles dynamic ordering better. 2017-09-06

Disastrous interview experience. Unable to enter building. Was this a test to weed out the idiots? Ran away and never came back. 2017-09-05

Guidelines for writing compelling yet substantively questionable essays, focused on rhetorical techniques over truth. 2017-09-04

2017-09-03

To write a viral blog post title, use a question format, focus on a single topic, and employ clickbait tactics to pique readers’ curiosity. 2017-09-02

2017-09-01

2017-08-31

Use CSS padding-top and position properties to create a full-width iframe with fixed 16:9 aspect ratio. 2017-08-30

Old Bitcoin wallet on a sketchy 2012 laptop. Block database corrupted but wallet.dat found. 2017-08-29

2017-08-29

2017-08-28

extern declares a variable without defining it, allowing the linker to find the definition elsewhere. This is useful when a variable is declared in one file but defined in another. 2017-08-27

2017-08-26

2017-08-25

2017-08-24

2017-08-23

2017-08-22

2017-08-21

Authoritative DNS servers provide definitive responses for their domains, while recursive DNS servers consult other servers to serve responses, caching results to reduce load on authorities. 2017-08-20

C’s _Generic is not true generics. It requires manual implementation of concrete type cases, unlike generics that automatically generate code for any type. 2017-08-19

2017-08-18

2017-08-17

Embedly respects Open Graph og:image meta tag for thumbnail selection. Adding it to vidr.io enables Reddit thumbnail. 2017-08-16

> is redundant; < alone suffices for all comparisons. I prefer it because it aligns with the number line. 2017-08-15

2017-08-13

Package a macOS app for distribution outside the Mac App Store by archiving it in Xcode, exporting it with a Developer ID signature, then creating a .dmg disk image. 2017-08-12

2017-08-11

Tracing a DNS lookup for ws-mt1.pusher.com using dig +trace reveals the iterative process of resolving the domain name, starting from the root name servers and following referrals to the top-level domain and authoritative name servers. 2017-08-10

<link rel="canonical" href="..."/> specifies the preferred URL of a page duplicated across domains. Search engines use this to determine which page to recommend. 2017-08-09

Moved GitHub Pages blog to Netlify, using custom domain, HTTPS, and redirects from the old site. 2017-08-08

2017-08-07

2017-08-06

2017-08-05

A DNS server in Go that responds to A queries for a hardcoded set of domain-to-IP mappings, using the miekg/dns package. 2017-08-04

2017-08-03

2017-08-02

2017-08-01

2017-07-30

Concurrent fwrites are not atomic and can lead to interleaving of characters, invoking undefined behavior. POSIX does not specify behavior of concurrent writes to a file, so applications should use concurrency control. 2017-07-29

2017-07-25

Presented “Go garbage collector” talk at GoWayFest in Minsk, met fellow Gophers, and did some tourism around Belarus and Ukraine. 2017-07-21

2017-07-05

2017-06-25

A long-term personal calendar that captures life goals, plans, and trajectories rather than daily schedules. Focuses on broad life stages and scenarios rather than precise event planning. 2017-06-06

2017-06-04

Granddad died. The unspoken practice of death-by-dehydration in the NHS. The Liverpool Care Pathway. Assisted dying in the UK. The importance of planning in end-of-life care. 2017-05-19

2017-05-07

The clear program clears the terminal screen using the escape sequence \033c, where \033 is the ASCII code for “escape” and 'c' is the command to clear the screen. 2017-05-06

2017-05-03

2017-05-02

2017-04-30

A macOS app that displays a webcam preview in a floating panel, using the AVFoundation framework. 2017-04-29

Kernels in Core Image operate on output pixels, using samplerCoord to find corresponding input pixels. sample then retrieves the color of the input pixel. Kernel can apply transformations by modifying the samplerCoord expression. 2017-04-28

2017-04-27

2017-04-26

2017-04-23

A neural network with one neuron that classifies binary-encoded natural numbers. We can decide whether the number is even, or whether it’s greater/less than 5. 2017-04-22

A .app is a macOS application bundle, a directory structure containing the executable and supporting files. The .app directory contains the real program binary, but cannot be directly executed. 2017-04-21

2017-04-20

2017-04-19

2017-04-18

2017-04-17

Businesses can take different legal forms, such as companies, sole traders, and partnerships. Companies are unique in that they are considered “legal persons” with their own finances and liabilities, distinct from their directors and shareholders. 2017-04-16

I demonstrate creating a public-private key pair, distributing the public key, and using a trusted third party (CA) to vouch for the public key. 2017-04-15

2017-04-14

2017-04-10

I want a service to manage product keys for software monetization, including key generation, signing, distribution, and verification, with optional machine or user licensing restrictions. 2017-04-09

2017-04-08

A TCP server that multiplexes multiple clients without select by looping over non-blocking sockets, maintaining a shared counter of total bytes received. 2017-04-07

A screencast about go tool trace, a profiling tool for Go applications. 2017-04-06

rxi/vec provides dynamic arrays in C, including push, pop, and iteration, without the need to manage array resizing and length. 2017-04-06

To set a socket as non-blocking, use fcntl to mark it with the O_NONBLOCK flag. This allows the socket to fail gracefully instead of blocking when no data is available. 2017-04-05

2017-04-04

2017-04-03

2017-04-02

2017-04-01

A “Replay with sound” button to control a muted video, implemented using the YouTube Iframe API. 2017-03-30

Prevent annoying video autoplay on mobile by detecting mobile devices and serving a manual play button instead. 2017-03-29

2017-03-28

2017-03-27

An analysis of the Framer.com promo video, highlighting its engaging music, timed animations, and succinct text slides. 2017-03-25

Asymmetric cryptography uses public and private keys. The private key can be derived from a password using a secure PRNG, avoiding the need to store the private key. 2017-03-24

Repetition is key for effective communication. Spaced repetition throughout the text, not just in the intro and conclusion, helps readers remember the main point. 2017-03-23

2017-03-22

Generating RSA keys, extracting the public key, encrypting with the public key, and decrypting with the private key. 2017-03-21

NSApplicationMain loads the MainMenu.xib file to create the application’s main menu and window. It first looks for the NSMainNibFile key in the Info.plist file, and if not found, it falls back to the first nib/xib file in the main bundle. 2017-03-20

2017-03-19

The @NSApplicationMain annotation in Swift is a macro that calls NSApplicationMain(...) to set up the Cocoa application’s UI event loop. 2017-03-18

2017-03-17

Avoid claiming unrealistic time estimates like “5 minutes” for product onboarding or tutorials. Realistic estimates like “a couple hours” are more honest and set appropriate expectations. 2017-03-14

2017-03-13

The openssl passwd command hashes passwords using the outdated crypt algorithm, with truncation to 8 characters - a poor choice for secure password hashing. 2017-03-12

Use the openssl s_client command to fetch a server’s SSL certificate chain, including the root certificate. 2017-03-11

Generate random bytes with openssl rand, which uses a PRNG seeded with entropy from ~/.rnd. 2017-03-10

2017-03-10

Encrypt and decrypt text using the openssl enc command with a password and AES-256 cipher. The encrypted text is base64-encoded. 2017-03-09

2017-03-03

2017-03-02

To fix misconfigured App Icons, create properly-sized PNG files and update the Contents.json file to reference the correct image files. 2017-03-01

2017-03-01

A technique to improve blogging focus by including a justification for each post, referring back to monthly targets. Allows room for off-the-wall posts. 2017-03-01

2017-03-01

2017-03-01

2017-03-01

A TCP server that uses pthread to serve multiple clients concurrently, with an “echo” server for each connection. 2017-02-28

The domain and type arguments to socket() describe the protocol family and socket type, respectively. The protocol argument specifies the actual protocol to use, which may be inferred from the domain and type. 2017-02-27

UTF-8 is a character encoding that can represent the entire Unicode character set. It’s variable-length, self-synchronizing, and an extension of ASCII. 2017-02-26

2017-02-25

2017-02-25

2017-02-24

2017-02-23

2017-02-22

Avoid using the word “simply” as it can come across as insulting to the reader by implying the task is easy or the reader is stupid. Instead, rephrase to be more objective and avoid comparatives like “simply” or “just.” 2017-02-22

A FIFO is a special file that allows inter-process communication. The mkfifo system call creates a FIFO, enabling processes to read from and write to it. 2017-02-21

2017-02-20

2017-02-20

Generate Intel and AT&T assembly with clang, demonstrating the difference in syntax between the two styles. 2017-02-19

2017-02-18

2017-02-17

To close a file descriptor in C, use the close system call. Multiple descriptors can reference the same underlying file or pipe. The pipe is only closed when all references are closed. 2017-02-16

A talk given with Will Sewell. Overview of Go’s concurrent garbage collector. 2017-02-15

2017-02-15

2017-02-14

French preposition examples for common spatial relationships like behind, in front of, next to, under, on, above, in, and between. 2017-02-13

Lamport timestamps measure time and causality in distributed systems. Timestamps are assigned to events, with the property that if event A happened-before event B, then A’s timestamp is less than B’s. 2017-02-12

2017-02-11

The happened-before relation models time in distributed systems, where events at different locations may not have a total order. It defines time using causality. 2017-02-10

2017-02-09

Reassessing daily routine - shifting sleep, work, and commute times to wake up earlier, improve sleep quality, and align with daylight hours. 2017-02-08

GeoDNS uses geo-IP to locate clients and connect them to the nearest server, reducing latency. 2017-02-08

To call a program from C, use `fork` then `execve`. There is no more direct way! 2017-02-07

2017-02-06

execve replaces the current process with a new one. It takes a path, an argument array, and an environment array. The process never returns unless execve fails. 2017-02-05

Realtime apps use protocols like HTTP streaming, long polling, WebSocket to enable live updates. Scaling pub/sub requires distributed servers and routing clients to the closest server. 2017-02-04

2017-02-04

2017-02-04

2017-02-03

Access environment variables in C by using the global environ variable, which points to an array of string pointers representing the environment. 2017-02-02

Reviewing January 2017 - covered networking, C/UNIX, WebRTC, and electronics. Plans to learn fundamentals of circuits, C compilation, UNIX process management, and WebRTC protocols. 2017-02-01

2017-01-31

2017-01-30

A multiplayer web-based version of the cooperative game Spaceteam, using Pusher for real-time communication between players. 2017-01-30

2017-01-29

To write to a file, open the file, mmap the file descriptor, then write to memory. 2017-01-28

2017-01-27

2017-01-26

Coulomb’s law describes the force between charged particles, which is proportional to the product of their charges and inversely proportional to the square of the distance between them. 2017-01-25

How to check if a 64-bit word contains a zero byte. A step-by-step example and a proof of correctness. 2017-01-24

2017-01-24

Integers in C are int by default, while suffixes like L and U denote long and unsigned types. Floats are double without a suffix. 2017-01-23

Literals are lvalues with addresses, while constants are rvalues without addresses. In C, only string literals are literals; other “literals” like numbers and characters are constants. 2017-01-22

2017-01-21

2017-01-20

2017-01-19

2017-01-18

The RTCDataChannel API lets us configure the delivery guarantees, including the ordered, maxPacketLifeTime, and maxRetransmits properties. 2017-01-17

2017-01-16

2017-01-15

2017-01-14

sigaction says what to do when a signal is received. signal is a simplified interface to sigaction. 2017-01-13

Executing do_something() N times in C using a while loop and post-decrement operator. 2017-01-12

To unregister a signal handler in C, use signal(signum, SIG_DFL) to reset the disposition to the default, or signal(signum, SIG_IGN) to set the disposition to ignore the signal. 2017-01-11

signal returns the old signal handler pointer for given signal number. 2017-01-10

2017-01-09

2017-01-08

The four wires in a USB cable are power (black, red) and data (white, green). One can power devices by connecting the ground and +5V wires, ignoring the data wires. 2017-01-07

2017-01-06

Using unique error codes with linkable documentation improves error reporting. Provide a central error page URL with each error message. 2017-01-05

Bitfields in C allow compact bit packing in structs, avoiding manual bitwise operations for greater safety and clarity, at the cost of some language complexity. 2017-01-04

2017-01-03

Efficient packing of game player data into 16 bits using bitwise operations on a uint16_t type. 2017-01-02

2017-01-01

2016-12-31

GCC’s ‘statement expressions’ allow inserting statements into expression positions. Behavior is unspecified. 2016-12-30

Redis uses length-prefixed strings with pointers into the middle of the allocation, allowing C-string operations on the string data. 2016-12-28

2016-12-27

2016-12-26

C array literals can use explicit indexes. The array length is determined by the largest explicit index. 2016-12-25

2016-12-24

2016-12-23

Useful to show how C represents various data types. 2016-12-22

htons and htonl convert values between host and network byte order, where network order is big-endian. ntohl and ntohs are the inverse functions. 2016-12-21

A C program that creates an HTTP server that responds with “Hello, world!” to every request. 2016-12-20

The syscalls needed for a simple UDP echo server are socket, bind, recvfrom, sendto, and close. 2016-12-19

2016-12-18

2016-12-17

2016-12-16

2016-12-15

A minimal TCP server in C uses the socket, bind, listen, accept, recv, send, and close syscalls to manage connections. 2016-12-14

errno lets you access error codes from system calls. It’s a global int. 2016-12-13

static functions in C are only callable within the translation unit they are defined in, not across the whole program. 2016-12-12

2016-12-10

Macros in C can define token replacements or function-like replacements. 2016-12-09

Arrays in C can “decay” to pointers, but are not inherently pointers. The size of an array is lost during decay. 2016-12-08

2016-12-07

2016-12-06

Set the C compiler in Makefile using predefined variable $(CC), which defaults to cc and can be redefined. 2016-12-05

A FILE is a C data type that represents an open file. It contains metadata about the file, such as its file descriptor and buffers. 2016-12-04

2016-12-03

const is a type qualifier in C that makes a variable unassignable, except during initialization. 2016-12-02

2016-12-01

realloc resizes an allocated memory block, copying contents if necessary. 2016-12-01

2016-11-30

Computing a pointer to unowned memory invokes undefined behavior, even without dereferencing! 2016-11-30

2016-11-30

2016-11-30

C array subscripts are defined as pointer arithmetic, where a[b] means *(a+b). This means a[b] is the same as b[a]! 2016-11-30

2016-11-29

2016-11-29

Use uintptr_t to count objects in C, as it can represent the largest possible pointer value. 2016-11-29

static in C can modify variable declarations inside and outside a function body, and function parameters. 2016-11-28

2016-11-27

void in a C function parameter list means the function takes no arguments, whereas an empty list allows for an unspecified number of arguments. 2016-11-27

The “K&R-style” function definition in C uses an initializer list to declare parameters, unlike the more common parameter type list. This old-style definition has significant semantic differences and should be avoided due to its potential for undefined behavior. 2016-11-27

2016-11-27

Avoid using ambiguous pronouns like “it” in technical writing. Refer to specific referents explicitly to improve clarity. 2016-11-25

A convention for expressing complex C types using typedef and a “reverse Polish notation” syntax to improve readability. 2016-11-24

The stack layout in C includes function arguments, return address, and local variables. Addresses decrease as you go through the arguments, and the stack grows downward with each function call. 2016-11-24

2016-11-23

A stream cipher works like a one-time pad, but uses a pseudorandom “keystream” from a PRNG seeded by a secret key and nonce, preventing attacks based on pad disclosure or reuse. 2016-11-21

Comparing meal replacement options Huel and Joylent, I choose Joylent’s vegan version. 2016-11-20

Symmetric cryptography uses a shared secret key for both encryption and authentication, providing confidentiality and integrity. We look at the API, HMAC, and Authenticated Encryption. 2016-11-19

2016-11-18

2016-11-17

2016-11-17

2016-11-17

2016-11-17

Progress comes from either copying or creating. Global progress since 1971 has been copying via globalization, except for computing. Startups create, not copy, because small groups, not large, can think anew. 2016-11-17

I try Vim. I give up after discovering that the cursor cannot sit at the end of a line. 2016-11-16

Serialize JSON in Swift with JSONSerialization.data(withJSONObject:options:). 2016-11-16

Daily blogging pledge; punishment for failure TBD. 2016-11-16

2016-11-16

2016-11-16

2016-11-15

2016-11-11

2016-08-10

Large working sets and low latency are incompatible with GHC’s stop-the-world garbage collector, which optimizes for throughput instead of latency. The collector’s pause times scale linearly with working set size. 2016-05-12

2015-01-28

2015-01-26

2014-10-25

2014-10-23

2014-10-11

2014-10-06

2014-10-04

2014-09-28

2014-09-19

2014-09-14

2014-09-13

2014-08-25

2014-08-24

2014-08-21

2014-08-19

2014-08-15

2014-08-13

2014-08-10

2014-08-09

The difference between estimates and deadlines, and why conflating the two can cause problems in project management. 2014-07-27

2014-07-27

2014-05-11

2014-05-10

Physical books and board games require energy and time to access, which creates a sense of focus. Virtual applications lack these constraints, leading to constant distraction. 2014-05-04

2013-12-24

A task management system using a directed acyclic graph (DAG) to represent task dependencies and priorities, allowing for more nuanced organization than a flat to-do list. 2013-12-19

2013-11-19

Flip a biased coin twice to get an unbiased outcome. Use HT and TH as the outcomes, ignoring HH and TT. 2013-11-16

2012-10-30

2012-04-16

2012-04-15

2012-04-12

2012-04-08

A visual programming language inspired by Haskell. 2012-02-27

2010-02-10

2010-01-25

2010-01-19

2010-01-19

2010-01-17

2008-02-15

2007-07-27

An ode to the Tetra Pak carton. 2007-05-23

2007-03-10

2007-02-09

The French Revolution, far from being a “liberal revolution”, was defined by violence from the start, with the Terror and subsequent instability being a logical continuation, not a deviation, from the events of 1789. 2006-12-11