
The Anatomy of a Z80 Gate (2014) - userbinator
http://www.devic.us/hacks/anatomy-z80-gate/
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userbinator
I've built simple CPUs out of logic gates and in simulators but the density of
the circuitry in ICs, even old ones, never ceases to amaze me. To put things
into perspective, that huge-looking wire coming onto the bond pad in the first
picture is already thinner than a human hair. The smallest features in this
30-year-old CPU are a fraction of that size, and on a modern CPU are even
smaller by a few orders of magnitude.

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derefr
The true wonder there, I think, is the science and craft of photolithography.

Moore's law wouldn't have had the constant march forward it had for 40 years,
if shrinking transistors smaller wasn't just the "simple" matter each time of
either developing a slightly more accurate projection system; or discovering a
quicker-reacting, less-runny, more-durable photoresist chemical.

We're running into the limits of this approach now, and having to look for
other interesting tricks, but there was a _lot_ of low-hanging fruit in
photolithographic precision, there for us to pluck, and pluck, and pluck, year
after year.

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digi_owl
> but there was a lot of low-hanging fruit in photolithographic precision,
> there for us to pluck, and pluck, and pluck, year after year.

As i grow older i find myself recognizing similar trends in a number of
fields. You have a initial slow takeoff period where basic science has to be
figured out. Then you have a steep climb as that science unlocks a bunch of
iterative refinements on the concept. And then you find yourself at a plateau
as new iterations become expensive and complex.

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Ericson2314
I someone I forgot said, everything supoosedly exponential is really
sigmoidal.

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bendykstra
Saul Griffith[1]. There's also Herbert Stein's Law: Trends that can't
continue, won't.

[1] [http://radar.oreilly.com/2007/11/its-not-exponential-its-
sig...](http://radar.oreilly.com/2007/11/its-not-exponential-its-sigmoi.html)

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gravypod
I wonder how much of the reverse engineering of these dies could be automated.
Looking at these dies I think a lot of this could be done image mapping and
then handing over annotated information of what pins go where to the person
doing the re work. Might be pretty helpful to someone doing these sort of
projects.

I'd also like to say kudos to the author. Great write up.

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em3rgent0rdr
reminds me of VLSI class in college.

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em3rgent0rdr
Why was I downvoted? Did you not layout these circuits in college. Oh, I know,
maybe you didn't take any computer engineering courses.

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tiben_
Link (or page) seems broken

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gus_massa
Probably the amount of HN traffic killed the server. Cache:
[http://webcache.googleusercontent.com/search?q=cache:L_uciFV...](http://webcache.googleusercontent.com/search?q=cache:L_uciFV2FiMJ:www.devic.us/hacks/anatomy-z80-gate/+&cd=1&ct=clnk)

