LaurieWired Profile picture
researcher @google; serial complexity unpacker; https://t.co/Vl1seeNgYK ex @ msft & aerospace
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Jul 10 4 tweets 2 min read
There’s a cursed C++ competition where programmers try to create the largest possible error message.

Finalists created ~1.5GB of error messages from just 256 bytes of source.

Preprocessor exploits were so easy, they had to create a separate division! Here's my favorites: Image
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One contestant experimented with C-Reduce; a way to search for C++ programs that create unusual compiler behavior.

Maximizing the fitness function for error as a reward, no templates, no pre-processor hacks.

Just nested parenthesis causing exponential error output! Image
Jul 9 5 tweets 3 min read
What happens when you freeze a process *perfectly*? RAM, VRAM, network, everything.

Imagine:
- Live-migrations of LLM training jobs
- time-travel debugging
- Surgical repairs of a crash moments before segfault

It’s called CRIU, and it’s already here: Image
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It starts with a mad Russian.

At least, that’s what a lead linux kernel dev called it:

“a project by various mad Russians to perform c/r mainly from userspace, with various oddball helper code...I'm less confident than the developers that it will all eventually work” Image
Jul 7 4 tweets 3 min read
Humans live at 10 bits per second.

The brain takes in ~11 million bits per second of sensory data, yet the inner conscious workspace is massively compressed.

Most people speak at ~40 b/s. How can we speak faster than we can think?

It's all about error correction: Image
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Speech may exceed the cognitive speed limit, but most of the bits are redundant.

Language is designed to withstand noise and mis-hearing. The 40bit “raw rate” is predictable from context.

A Caltech study shows the effective payload collapses to <13 b/s when stripped. Image
Jul 5 4 tweets 2 min read
Whole-home lithium power used to be a rich man’s game.

Now it’s “high-end graphics card” territory.

This is a $2500, lithium polymer battery that would power an entire US residential house for >24hr.

China is *crushing* it on kilowatt hours per dollar. Image Let’s put it into perspective. That battery is 2x the kWh of a tesla powerwall 3.

Each powerwall will set you back $15k a piece.

Residential battery setups usually cost $1000 per kWh.

This is $80 per kWh. Image
Jul 4 4 tweets 2 min read
Ubuntu’s next version won’t work on 90% of current RISC-V computers.

Got a raspberry-pi style RISC-V board? Yeah, not gonna work.

This isn't a bad thing.

It’s actually a genius move that will force the industry in the right direction; helping consumers in the process. Image
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Here’s the problem with a debian-style “we support everything” mentality:

Many board makers slap cheap, borderline out-of-spec Chinese RISC-V CPUs onto a PCB and call it a day.

The bare minimum for a functional OS.

Many are riddled with hardware-level vulnerabilities (c908)! Image
Jun 20 5 tweets 3 min read
A lone Boston coder rewrote BIOS in 1984.

IBM wanted to sue. The programmer's clever loophole became the model for legally defensible reverse engineering.

You’ve probably been booting his descendants ever since. This is how Phoenix Technologies got away with it: Image
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The case Apple v. Franklin held that BIOS could be protected by copyright.

IBM already crushed other competitors citing the case law.

Phoenix created a bizarre ruse. What if an engineer had never *seen* IBM’s specification…and thus came up with the idea organically? Image
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Jun 12 4 tweets 3 min read
Grep is actually an acronym; originally started as a ed command:

:g/<re>/p

G - global search. <re> - Regular Expression, P - print.

It was invented to run Natural Language Processing on The Federalist Papers; the precursor to the US Constitution. Yes, really. Image
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Lee McMahon, computer scientist at Bell Labs, was working to clarify the authorship of The Federalist Papers.

85 essays, all published under a pseudonym, it’s been a historical puzzle for a century+

The trick? De-anonymization by isolating word-frequency statistics. Image
Jun 3 4 tweets 2 min read
A squadron of F22’s was once taken out by an imaginary line.

On a mission to Japan, an unforeseen software bug occurred crossing the international date line. Longitude swaps from W179.99 to E180 degrees.

Navigation, comms, and even fuel management went down! Image
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This wasn’t a simple "turn it on and off again” fix; something was seriously wrong. Reboots weren't helping.

According to Maj. Gen. Sheppard:

“…all systems dumped and when I say all systems, I mean all systems...they could have been in real trouble." Image
May 27 4 tweets 2 min read
Want to recognize a song from just a few seconds of distorted audio?

Use Constellation Maps.

The math is brilliantly simple.

With just a handful of bytes; discarding 99% of the waveform, you can recognize a unique fingerprint across hundreds of millions of tracks. Image
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First, chop up the audio into few-second windows.

Take an FFT of the waveform, then extract the local peaks. Each maximum becomes a “star” on an xy plot of time vs frequency.

Pair nearby stars into clusters and hash the result. Boom, a noise-resistant fingerprint. Image
May 23 4 tweets 3 min read
I miss the insanity of 80s processor design.

Intel’s iAPX 432 was a “micromainframe”.

It had no general purpose registers, supported object orientation *directly*, and performed garbage collection on-chip.

It was also 23x slower than an 8086. Here's why it failed. Image
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Intel targeted Ada so aggressively that C support was an afterthought.

Problem was, particularly at the time, the Ada compiler was extremely untuned and immature.

Scalar instructions were basically never used; *everything* was huge object-oriented calls. Image
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May 22 5 tweets 3 min read
NTIRE is the coolest conference you’ve never heard of.

Deleting motion blur? Sure.
Night Vision? No problem.

Every year, labs compete on categories like hyperspectral restoration, satellite image enhancement, even raindrop removal (think car sensors)! Some highlights -> Image Low-light enhancement is always popular.

Retinexformer, shown here got 2nd place in the 2024 contest.

A *TINY* transformer-based model, it runs in about 0.5 seconds for a 6K image on a single 3090. Only 1.6M parameters (<2MB weights at INT8)! Image
May 21 5 tweets 3 min read
What if an OS fit entirely inside the CPU’s Cache?

Turns out we’ve been doing it for decades.

CNK, the OS for IBM’s Blue Gene Supercomputer, is just 5,000 lines of tight C++.

Designed to “eliminate OS noise”, it lives in the cache after just a few milliseconds of boot. IBM Blue Gene Kernels that “live” in the cache are common for HPC.

Cray’s Catamount microkernel (~2005) used a similar method for jitter free timing.

Huge Pages, Statically Mapped Memory, and a lack of scheduling are all typical aspects of these systems.

What about the modern era? Cray XT2
May 13 5 tweets 3 min read
TDP (Thermal Design Power) of CPUs is a garbage metric that misleads consumers.

In the Pentium era, a 89W TDP meant just that; expect to dissipate 89W of heat in the worst case.

With Alder Lake, a 125W CPU can draw ~241W indefinitely!

Here's the goofy math: Image
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CPU’s didn’t really know how to idle until the early 2000s. They just kinda ran full bore all the time.

With the introduction of C-States, various parts of the processor could be shut down, saving power when the computer was doing nothing.

Of course, this was HUGE for laptops. Image
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May 12 6 tweets 4 min read
What if humanity forgot how to make CPUs?

Imagine Zero Tape-out Day (Z-Day), the moment where no further silicon designs ever get manufactured. Advanced core designs fare out very badly.

Assuming we keep our existing supply, here’s how it would play out: Image
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Z-Day + 1 Year:

Cloud providers freeze capacity. Compute Prices skyrocket.

Black’s Equation is brutal; the smaller the node, the faster electromigration kills the chip.

Savy consumers immediately undervolt and excessively cool their CPUs, buying precious extra years. Image
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Mar 27 4 tweets 2 min read
HTTP code 418 began as an April Fool’s prank to signal “I’m a teapot”.

Later, it acted as a DDoS defense mechanism during the Ukraine war.

In 1998, the HTCPCP standard defined communication for…coffee pots.

Turns out, that wasn't the only thing brewing. Image
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Even the original RFC pokes fun at itself, stating:

"This has a serious purpose – it identifies many of the ways in which HTTP has been extended inappropriately."

Despite the joke, frameworks began treating the error code as valid; leading to unexpected consequences. Image
Mar 23 4 tweets 2 min read
China’s leap in computer science stemmed from a Soviet disagreement.

Soviet computer tech exchanged between the two countries, until tensions between Mao and Khrushchev abruptly ended the swap.

Suddenly isolated, China was forced to create their own computer, the Model 107. Image
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For CS researchers, this was brutal.

1000+ Soviet experts were ordered to leave the country within the month. Their tech was the backbone of China’s early machines.

Self-reliance was the new game, yet they were intellectually isolated from the rest of the world. Image
Mar 21 4 tweets 2 min read
Water can solve differential equations.

Lukyanov, a Soviet engineer, was trying to calculate heat transfer in concrete structures.

Hand calculation was cumbersome, so he developed an analog computer to physically model the math relationships.

It worked *really* well. Image Known as the “Water Integrator”, it solved partial differentials with just gravity, with an error rate around 2-3%.

Because of the simplicity of “programming” with valves, it was successfully used for Geology, thermal physics, metallurgy, and even rocket engineering. Image
Mar 18 5 tweets 2 min read
The term “Hacker” originated from a bunch of MIT students obsessed with model trains.

In the late 1950s, the Tech Model Railroad Club was split into two primary factions:

- Knife and Paintbrush
- Signals and Power (S&P)

S&P played fast and loose; disliking authority. Image S&P hated formal engineering procedures.

They wanted to use the multi-million dollar mainframe (IBM 704) in Building 26 to calculate their control system.

Turns out, time on that mainframe was restricted to “important” things like defense (lame). Image
Mar 13 4 tweets 2 min read
Ken Thompson, upon receiving the Turing award, wrote a terrifying paper.

“Reflections on Trusting Trust” illustrates a scenario of original sin.

Because the C compiler is written in C itself, a compromised compiler can self-replicate with no trace in source code. Image If you can’t trust your compiler, you can’t trust any compiler you build with it either.

Sin in the family tree, no matter how distant, can propagate to your clean code even decades later.
Mar 10 5 tweets 2 min read
In 1960s Soviet Russia, a computer network was proposed decades before the internet.

“ОГАС” had concepts of Cloud Computing, virtual currencies, and a data-driven economy.

At a cost of $300 million, 300k operators, and a 30-year rollout, it was killed by politics. ОГАС, National Automated System for Computation and Information Processing Glushkov, the creator, envisioned technology as a tool for government optimization.

The claimed savings returns would be fivefold over a 15 year period.

Banks, factories, and offices hooked up to cities; with information further distilled to a central hub at Moscow. Image
Mar 4 5 tweets 2 min read
Modern Computing is only possible because Honeywell filed a lawsuit a few minutes early.

The invalidation of ENIAC’s patent in Honeywell vs Sperry Rand placed the invention of the digital computer into public domain.

Without it, the U.S could have easily lost tech dominance. Image Sperry Rand wanted $2.3 Billion (inflation-adjusted) from Honeywell, for infringing on “arithmetic operations using electronic circuits”.

The ENIAC patent was so broad, they could legally demand royalties for *all* general-purpose electronic computers. Image