TIL

The Pygmalion effect is the idea that people perform better when others expect more of them, and worse when expectations are low, because expectations subtly change how they are treated and how they see themselves.

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A TOCTOU (Time-of-Check to Time-of-Use) race condition is a software vulnerability occurring when a program checks a resource's state (e.g., file existence) but the resource changes before it is used. Attackers exploit this tiny timing gap to manipulate the resource, causing unauthorized actions or privilege escalation.

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A Veblen good is a type of luxury good where demand increases as the price increases, contradicting the law of supply and demand, resulting in an upward-sloping demand curve. Higher prices make them desirable as a status symbol, like expensive watches and cars.

Not all luxury goods are Veblen goods. Some luxury items do in fact provide a premium experience or feature. Veblen goods typically are purchased as a sign that someone can afford to purchase it.

Veblen goods are named after American economist Thorstein Veblen who first wrote about the phenomenon.

The phrase was coined by Western observers in the 1940s to describe religious movements in Melanesia that formed after contact with Allied forces in World War II. Indigenous people saw large amounts of manufactured goods (“cargo”) arrive via military logistics, and after the troops left they built symbolic airstrips, mock planes, and other rituals in hopes of attracting similar cargo again.

The label was applied by outsiders, not by the communities themselves, and later broadened metaphorically (e.g., Feynman’s “cargo cult science”) to describe imitating form without understanding substance.

Everyone knows ⌘⇧3 for taking screenshots on a Mac, or ⌘⇧4 for screenshotting a region. But I never thought to ask: what happened to ⌘⇧1 or ⌘⇧2? Turns out: they were originally designed for ejecting floppy disks. I guess people did a lot of ejecting back in the day.

I’ve since remapped ⌘⇧1 with Cleanshot to take OCR screenshots (copy and text in the image directly to my keyboard, rather than saving the image directly).

I learned this computer fun fact, and many others, from Marcin Wichary’s delightful website and article that everyone should subscribe to.

cd - takes you back to your previous directory, like a navigation undo in the terminal.

~/projects   $ cd /etc
/etc         $ cd -
~/projects   $

No more spamming cd .. or retyping full paths.

Same pattern works with git checkout -—switches to your previous branch.

SIMD (Single Instruction, Multiple Data) lets a CPU do the same math on multiple numbers at once. If you have a list of 1,000 numbers and need to double each one, a normal CPU does it one at a time. SIMD does 4 or 8 at a time in a single step.

Where it matters: video codecs, game engines, ML inference, image processing—bulk numeric work on uniform data. Libraries like numpy and ffmpeg use SIMD under the hood.

Why not use it everywhere?

• Only works for the same operation on independent data—most logic is sequential or branching
• Memory is usually the bottleneck, not compute
• SIMD hates if statements
• Data must be packed contiguously in memory

You benefit from SIMD without touching it. It's plumbing—good to know it exists, rarely something you write yourself.

Sumo oranges (dekopon) are a Japanese cultivar from 1972—a cross between kiyomi tangor and ponkan mandarin. The distinctive bump was initially considered ugly and they flopped commercially for two decades. In the late 90s, a growers' cooperative figured out a curing process that ensured consistent sweetness.

The easy peel trait is genetic. The albedo (white pith) naturally separates from the flesh, so the rind practically falls off. The segment membranes are also thinner than most mandarins—less fiber, more juice release.

Sumo oranges arrived in the US in 2011, marketed as "Sumo Citrus" by a California grower who licensed the cultivar. They have a short season (January–April), are usually hand-harvested, individually wrapped, fragile, and don’t ship well—hence, $3-4 per fruit.

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In software development, a noisy neighbor refers to a situation in multi-tenant environments (like cloud infrastructure or shared servers) where one tenant consumes a disproportionate amount of shared resources—CPU, memory, network bandwidth, disk I/O—degrading performance for other tenants on the same system.

It's borrowed from the apartment analogy: one loud neighbor ruins the experience for everyone else in the building.

x86 is a design language for computer processors—the chip that acts as your computer's brain. If processors are engines, x86 is one particular engine design philosophy that's dominated personal computers for 40+ years.

When someone says "x86," they're referring to processors that understand a specific set of instructions. It's like how some cars run on gasoline and others on diesel—x86 processors "run on" x86 instructions.

The weird name comes from Intel's chip model numbers in the late 70s and 80s:

• 8086 (1978)
• 80286
• 80386
• 80486

They all ended in "86." So people just started calling the whole family "x86."

The main alternative today is ARM (used in your phone, Apple's M-series Macs, and increasingly in servers). The car analogy: x86 is like a big V8 engine—powerful, proven, but thirsty. ARM is like a modern turbo-4—efficient, increasingly powerful, better for battery life.

x86 advantages:

• Massive software library (everything just works)
• Mature tooling and developer knowledge
• Still dominates servers and high-performance computing

x86 disadvantages:

• Carries 40 years of design baggage for backwards compatibility
• Less power-efficient than ARM
• Harder to innovate because you can't break old software

The core tension: x86's greatest strength (compatibility) is also its greatest weakness (complexity and power consumption). ARM started fresh with mobile constraints, which is why it's more efficient.