On Reading SRAMs in IR Images, and Establishing Bounds on Trust

Last month’s name that ware demonstrates that even though non-destructive IR imaging is not capable of resolving an individual bit cell, at least at 22nm it is still possible to constrain the number of bits in an SRAM macro.

An important step in establishing trust in a computer is measuring all of its state and confirming that nothing is amiss. A typical trusted boot would make a point of zeroing and/or patterning & hashing all the known bits of memory in a system. This process helps constrain the amount of malicious or foreign code that could be hiding in the system.

Physical...

Microcode inside the Intel 8087 floating-point chip: register exchange

In 1980, Intel introduced the 8087 floating-point chip, a co-processor that made floating-point operations up to 100 times faster. This chip was highly influential, and today most processors use the floating-point standard introduced by the 8087.

The 8087 uses complicated algorithms to accurately compute functions such as square roots, tangents, and exponentials. These algorithms are implemented inside the chip in low-level code called microcode. I'm part of a group, the Opcode Collective, that is reverse-engineering this microcode. In this post, I take a close look at the microcode for one of the 8087's instructions—FXCH—and explain how the microcode works. The FXCH (Floating-point Exchange) instruction exchanges two floating-point...

It's hard to justify buying a Framework 12

My nephew just graduated high school, and wants a laptop. When he decides what computer to buy, price (or more precisely, value) is the most important attribute.

Apple's MacBook Neo upended the 'value laptop' equation—Apple's not supposed to be both the cheapest option and the best value... but it seems like that's squarely where the Neo landed for the good-but-cheap laptop category.

My nephew is also my godson, and to kick off his computing journey, I thought I'd let him choose from a Framework 12 I bought to test, or the MacBook Neo I bought a couple months ago to use around...

MSDSL. Два мегабита по двум проводам

Приветствую всех!

Не так давно я уже рассказывал про ADSL и всё, что с ним связано. Когда-то давно благодаря этой технологии многие впервые смогли выйти в интернеты на высокой скорости, а кто-то до сих пор пользуется таким подключением из-за дешевизны или за неимением альтернатив.

Но ADSL — технология асимметричная: скорости приёма и отдачи отличаются, а модем подключается только к провайдерскому оборудованию (DSLAM). Сегодня же мы поговорим кое о чём куда менее известном среди простых пользователей: о симметричных системах. Узнаем, как выглядит их оборудование, где оно применялось и как заставить его работать. Как водится, будет много интересного.

Tuning in FM Radio on a 3D Printer Heatbed

Pooch from Repkord dropped by my studio while he was in St. Louis, and asked a simple question:

Can a 3D printer's heatbed act as an antenna?

A fair question, as many an antenna is embedded in a PCB these days... and the traces on a PCB heatbed like the one used in Prusa's Core One look kinda like an antenna, if you squint the right way.

Really, anything (or anyone) can be an antenna, given enough power.

Эксперименты с WAP в 2026 году

Эта статья - продолжение моей предыдущей статьи: Создаем собственную базовую станцию при помощи SDR. В прошлый раз я экспериментировал с 2G GPRS, но на старых телефонах эта технология не поддерживается, а мне хотелось запустить WAP именно на таком. О том, как вернуться в эпоху до распространения GPRS - читайте далее.

OpenTitan’s Pre-Silicon Security Simulation and Verification

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I patched iozone for better disk benchmarks on modern macOS

A decade ago, I settled on iozone for disk benchmarking on all my systems. Tools like fio ('Flexible IO' tester) are a little more capable for raw disk performance testing, and other tools test network-scale filesystems better, but iozone gives me an easy overview of real-world disk performance across hard drives and SSDs, and runs on Mac, Windows, and Linux (and a smattering of other OSes).

It's been around since 1991, and is still updated today—in fact, the two latest updates (version 509 and 510) contain patches I sent in to get iozone to compile on Apple Silicon Macs running newer...

Ремонтируем аналоговый XY-самописец Endim 622

В узких кругах я широко известен как адепт цифровой схемотехники на электронной базе ушедших эпох. Дайте мне стрелку Пирса — и я сделаю на этом Электронно-вычислительную машину, будь то Релейный компьютер или ламповый. По силам даже на струйной логике — который в интернетах почему-то известен как паровой.
При этом, университет я заканчивал как специалист по электротехнике в целом и по аналоговому электроприводу в частности. Многоконтурный следящий электропривод с тиристорным преобразователем и системой управления на операционных усилителях — что может быть прекраснее? Но аналоговые устройства я каждый раз я обходил стороной.
Впрочем, нельзя вечно этого избегать, поэтому очередная спонтанная покупка на avito —...

Reverse engineering circuitry in a Spacelab computer from 1980

Spacelab was a reusable laboratory that could be carried in the cargo bay of the Space Shuttle, providing lab space for astronauts and experiments. Spacelab was controlled by a French-built minicomputer, called the Mitra 125 MS. Unlike modern computers, this computer didn't contain a microprocessor chip. Instead, its 16-bit processor was constructed from several boards of chips. In this article, I reverse-engineer one of the processor boards, shown below, part of the computer's Arithmetic/Logic Unit (ALU).

Spacelab consisted of a pressurized cylindrical laboratory that held experiments, computers, and work areas for researchers. A tunnel...