Viewing profile — kens

I'm too busy trying to reverse-engineer the Intel 8087 floating-point chip, although it would be interesting to look at this puzzle chip.

Thanks for filling in the details! I figured that I was already going into too much history in my article :-)

Cute, but the steps don't make sense. E.g. each cycle shows both an ion gun and wire deposition. But only the first layer would use the ion gun, and only the following layers would…

Author here. I've powered up another tube module from the IBM 604, so let me know if you have questions...

It's kind of hopeless to try to prove that a microprocessor works according to spec, since you're dealing with physical objects in the real world. For instance, early versions of I…

Serious question: does Figure 1 in the article make sense to anyone? If you understand the symbols, do you look at the diagram and it's clear how logistics works?

The short answer is the "14-day" rule, which doesn't allow development of the embryo beyond 14 days. The article gives specifics under the heading "Ethical and legal compliance"

Oops, I've fixed that now.

It's unlikely that you'd get a simultaneous tie; you'd expect one computer to go bad before the other. But I think in that case, the astronauts switch to the Backup Flight System, …

There have been a fair number of GPC failures [1], and computers have been voted out. I haven't looked closely enough to see how many were "disagreements" versus hard failures or s…

Sorry, I don't know anything secret :-)

I don't know if these boards were flown. They were coated with conformal coating (which I hate for reverse-engineering), which is usually omitted from prototypes. I believe that bo…

Yes, the low density and TTL chips (instead of MOS) helped against radiation. When the Shuttle computers moved to semiconductor RAM, they needed extensive error correction, as well…

Author here if you have questions...

What I'm interested in is the best starting word. Using Shannon entropy, the paper finds that it is "tares".

CAD was a very incremental process. Early chips were drawn by hand and the Rubylith masks were cut by hand with the help of a Coordinatograph. Later, Intel used a Xynetics plotter …

Yes, you can use a "logarithmic shifter". The CDC 6600 supercomputer (1964) used that approach. The tradeoff is that you need more stages with the logarithmic approach (six versus …

That's a very interesting board! It came out in 1976 (four years before the 8087) and cost $499 assembled, equivalent to $2900 in current dollars, so it was expensive. It was reall…

I'm here now if anyone has questions. I can't be online all the time :-)

I score 1%. Is that good or bad? https://www.intheweights.com/p/ken-shirriff

On a complete tangent: there's a drawing of an iceberg halfway through the article, the typical vertical shape with 10% above the surface. It turns out that icebergs don't float th…

I don't think you can count PDP-10 things (Internet, BASIC, 8080 emulator) to support the influence of the PDP-11, since they were completely different computers. The PDP-10 was a …

I'd suggest the Datapoint 2200 as the most influential minicomputer of all time since half of you are using an instruction set based on it and it is largely responsible for the cre…