Logical Art
Interactive explanations of difficult machines.
A hole punched in card stock in 1928 and a neural network trained in a browser tab are the same idea a century apart. Everything here sits somewhere on that line, and all of it is working: every number live, every failure honest, nothing faked.
New here? Punch a card takes about a minute. Front Panel (on frontpanel.dev) is the one to sit down with.
Showing 42 built
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Baudot
Five bits cost the same for every letter, so frequency bought holes instead of time.
/bits/baudot/ -
Rangekeeper (on rangekeeper.dev)
The answer is on both sides of the equation, so it had to be a machine.
rangekeeper.dev -
Stored Program planned
The instructions are numbers, in the same memory as the numbers.
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Trigger
Every sweep starts at the same point, so repetitions land on each other instead of smearing.
/nibbles/trigger/ -
Bit, Nibble, Byte
Why a byte is eight, why a nibble is one hex digit, and how the bases fell out of the hardware.
/bits/bit-nibble-byte/ -
Transistor planned
A weak signal controls a stronger one, and two of them make NOT.
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Huffman
The two rarest symbols marry, and the tree that falls out is provably the best.
/nibbles/huffman/ -
Score Reel
An electromechanical table cannot add, it can only count at the speed of a motor.
/nibbles/score-reel/ -
Page Fault planned
The address exists even when the memory does not.
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CPU Cache planned
Reading memory twice is not the same operation twice.
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Fifteen Planes
A generator that passes every test you thought to run, and lands on fifteen planes.
/nibbles/fifteen-planes/ -
Line Mode planned
You could telnet to port 80 and be the browser, and then you could not.
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Front Panel (on frontpanel.dev)
A working 1975 Altair 8800 you program by flipping switches.
frontpanel.dev -
Diffie-Hellman
The secret is not among the things that crossed the wire, and everything that did is on the screen.
/nibbles/diffie-hellman/ -
Zero Address
Assembly for a processor nobody built, so one file runs everywhere.
/nibbles/zero-address/ -
Branch Prediction planned
The processor runs an instruction before knowing whether it should exist.
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Eight Sprites
Eight per scanline and the ninth is dropped, which is why they flickered.
/bits/eight-sprites/ -
Slow Start
The network never says how fast you may send, so TCP finds out by hurting it.
/nibbles/slow-start/ -
Write-Ahead Log planned
The database says done before half the database has been written.
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JPEG planned
Throw away numbers, not pixels.
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Winsock (on winsock.dev)
The two seconds after the modem stopped screeching, before anything worked.
winsock.dev -
Merge Collapse
The sort in every standard library, and the invariant it did not keep.
/nibbles/merge-collapse/ -
Merkle DAG planned
A commit holds hashes pointing at hashes, and never holds your repository.
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Longest Chain planned
History is whatever was most expensive to produce.
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LLM Lab (on watchitlearn.com)
Train a tiny language model and watch every number as it learns.
watchitlearn.com
Why these machines
A hole punched in card stock and a weight in a matrix are the same kind of object: a decision written down somewhere a machine can read it back. Everything here is a point on that line, and the line is the reason the set is what it is.
The big ones are not chosen from a syllabus. Each is something I actually sat in front of. I toggled a program into an Altair through the front panel switches in the late 1970s, and ran bulletin boards in the 1980s when getting online meant listening to a modem negotiate at 300 baud. In college and on contract work I punched decks and leased mainframe time by the hour on an AS/400 and a 9221, in FORTRAN, COBOL, PL/I, RPG and REXX. I served aboard the USS Missouri in Desert Shield and Desert Storm, where the guns were still being aimed by a mechanical analog computer designed in the 1930s. In 1994 I was at Spry when the web stopped being something you had to already be inside. Now I build with language models.
That constraint costs a lot of good subjects, and it buys the one thing this studio is for: I can tell you where the simulation departs from the real machine, because I used the real machine. Every one of them ends with a section saying what is faithful, what is approximated, and what is simply wrong on purpose, with the sources that settle it.
The work is sized in three, named after what they are. The rule about my own history applies only to the largest, which is what lets the small pieces cover subjects that are worth building and are nobody's biography.
- Bit
- One idea, with nothing in it handing off to anything else. Lives on logicalart.us. 10 here, 8 built
- Nibble
- One mechanism in three or four stages, each one reachable only through the one before. Lives on logicalart.us. 35 here, 28 built
- Byte
- A complete machine you operate, on its own domain, with its own sources and honesty ledger. 7 here, 6 built
Nothing here is a video of a machine. If a number is on the screen, something computed it. How that is checked, what counts as a source, and what happens when this is wrong: the method. New machines arrive in the feed.