A Communist Apple II and Fourteen Years of Not Knowing What You're Testing

It is Friday. KPMG, the consultancy behemoth that delivers business Venn diagrams for outrageous prices, informs us that 70 percent of UK business leaders will keep spending on AI even when they can’t prove it does anything — the consultancy helpfully suggests we stop calling it “investment” and start calling it a “strategic enabler for enterprise-wide transformation,” which is the corporate equivalent of renaming a hole in the ground a “subterranean opportunity space.”

Meanwhile, OpenAI has put Stargate UK on ice, citing the cost of electricity and the regulatory environment, mere months after announcing it during a Trump state visit — one assumes the due diligence was conducted with the same rigour as the naming convention.

AMD’s AI director reports that Claude Code has become “dumber and lazier” since February, based on analysis of 6,852 sessions and 234,760 tool calls, which is the most thorough performance review any AI has received and rather more than most human employees get. One notes that the AWS CEO, asked whether AI is overhyped, described the question as “one of the funnier questions I get” and then asked a room full of people who had each paid $4,000 to attend an AI conference whether they believed in AI. Asking turkeys to vote on Christmas, as it were.

In this climate of expensive ~~credulity~~ naïveté, I thought we might spend a Friday doing something that we do on Fridays: looking backwards. Reverse engineering — the art of taking something apart to understand what it does — is the intellectual opposite of the current AI approach to technology, which is to build something enormous, declare it transformative, and hope nobody asks what it actually computes.

The Правец (Pravetz): Bulgaria’s Apple II, Give or Take an Iron Curtain

I grew up using Правец (Pravetz) computers — forgive the Cyrillic, but we Bulgarians invented the alphabet, even though half the Slavic world claims the credit, and besides, it makes any noun look like classified military hardware. Every Bulgarian of a certain age used one. The Правец 82 was the machine in my school, with its yellow plastic case, black keyboard, red RESET key, and the unmistakable aura of a computer that had been reverse-engineered from a capitalist original by engineers who had never seen Cupertino and didn’t need to.

My first encounter with a personal computer was typing in a BASIC program that drew Lissajous figures in hi-res graphics. I was in the fourth grade. It was 1987. But I am digressing.

The story of the Bulgarian computer is worth telling properly. In 1979, engineer Ivan Marangozov at the Institute of Technical Cybernetics and Robotics (ИТКР) in Sofia built the IMKO-1 — the first Bulgarian personal computer. It was a clone of the Apple II, and “clone” is doing some diplomatic heavy lifting here: the ROM was identical, the schematics were identical, the 6502 CPU ran at the same 1 MHz. The differences were a metal case that could double as ballast, a linear power supply heavy enough to qualify as exercise equipment, and the replacement of lowercase Latin with uppercase Cyrillic — because behind the Iron Curtain, you didn’t do lowercase. The keyboard used 7 bits for character codes, so Cyrillic overlapped with Latin lowercase. A limitation, but also an engineering decision that had a certain brutal elegance: you get one alphabet at a time, comrade, and you will type in capitals.

The rumours of how this was accomplished are better than the facts. The Bulgarian intelligence services allegedly sent operatives to procure Apple IIs from the West — less James Bond, more cartoon characters getting drunk on capitalist Coca-Cola while trying to buy a computer with a heavy accent and a suitcase full of leva (the Bulgarian currency, not then known for its convertibility). More interesting is what happened next: an institute in Sofia was reportedly tasked with decapping the ICs, lifting the netlists under a microscope, and reproducing them with socialist lithography — the equipment for which was probably lifted from the Dutch. The reasonable question is why arguably clever people went through all of this when designing an ALU from scratch is not that difficult, but we will leave this armchair philosophy question to the LLMs. They have the confidence for it, if not the answer.

Today, people do this sort of thing voluntarily and for fun. The 6502.org community hosts dozens of homebrew computer projects — enthusiasts building 6502-based machines from scratch on breadboards, complete with VGA output and SD card storage, using parts that are still in production. The MOnSter 6502 takes it further: a fully functional 6502 processor built from 3,218 discrete transistors on a circuit board the size of a dinner plate, with LEDs showing the state of every register. What the Bulgarian state did with an institute and a five-year plan, hobbyists now do in garages on weekends.

Marangozov was, depending on your perspective, either rightfully accused of cloning the Apple II or laudably credited with delivering computing to an entire country that couldn’t buy one. The truth is both, and neither is shameful. Apple II schematics were published. Steve Wozniak intended the design to be understandable. What Marangozov and his team did was take a published design, source the components (Bulgarian and Soviet clones of American chips — clones all the way down), adapt the character set, and manufacture hundreds of thousands of units that shipped to every school and scientific institute in the Eastern Bloc. By the mid-1980s, Bulgaria was producing 40 percent of the personal computers used in COMECON countries. Not bad for a country whose communist leader Todor Zhivkov — a peasant’s son turned printer’s apprentice who rose through the party ranks on the strength of Soviet patronage and the convenient absence of anyone more threatening — happened to have been born in the village that gave the computers their name. Правец was a hamlet of no consequence until Zhivkov turned it into a town by decree in the 1960s; by the 1980s it was assembling the flagship technology of the Eastern Bloc. One does not need a diagnostic engine to detect the fault in this particular circuit of patronage.

The later models improved substantially. The Правец 8M integrated a Z80 alongside the 6502, letting it run CP/M. The 8A was a proper Apple IIe clone with expandable memory. The military version had an integrated terminal design, because of course it did. There was even a Правец 8D, which broke ranks entirely — it was a clone of the British Oric Atmos, presumably because even Bulgarian engineers sometimes want variety.

The point is not that Bulgaria copied Apple. The point is that reverse engineering — understanding a design well enough to reproduce and adapt it — was how an entire generation of engineers learned computing. We didn’t have access to Stanford or MIT. We had schematics, soldering irons, and a cheerful disregard for intellectual property law that was, in fairness, philosophically consistent with the economic system. The Правец was my first computer. Everything I know about hardware starts there: with a 6502, 48 kilobytes of RAM, and a cassette recorder that worked when it felt like it.

Hayes and the ISCAS Circuits: What Were They For?

Now here is a story about reverse engineering that is less well-known outside the EDA community but is, in its own way, just as delightful.

The ISCAS-85 benchmarks are the standard test circuits for digital design research. If you work on test generation, fault diagnosis, synthesis, or timing analysis, you have used them. They were released by Franc Brglez and Hisashi Fujiwara in 1985 as a “neutral netlist of 10 combinational benchmark circuits” — gate-level descriptions of real circuits, stripped of context, for the research community to use as common benchmarks.

There was just one problem. Nobody told the research community what the circuits did.

For fourteen years, thousands o