#computing history

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(^Commodore Colt)

From 1984-1991, Commodore manufactured and sold their own PC computers, alongside their own C64/128 and Amiga computers.

Well outside that one AVGN meme, half-bit isn't really a thing, but the answer is a bit weirder in other ways! The current most prominent CPU designs come from Intel and AMD, and Intel did produce 4-bit, 8-bit, 16-bit, 32-bit and 64-bit microprocessors (although 4-bit computers weren't really a thing). But what came before 4-bit microprocessors?

Mainframes and minicomputers did. These were large computers intended for organizations instead of personal use. Before microprocessors, they used transistorized integrated circuits (or in the early days even vacuum tubes) and required a much larger space to store the CPU.

And what bit length did these older computers have?

A large variety of bit lengths.

There were 16-bit, 32-bit and 64-bit mainframes/minicomputers, but you also had 36-bit computers (PDP-10), 12-bit (PDP-8), 18-bit (PDP-7), 24-bit (ICT 1900), 48-bit (Burroughs) and 60-bit (CDC 6000) computers among others. There were also computers that didn't use binary encoding to store numbers, such as decimal computers or the very rare ternary computers (Setun).

Boards of Canada played on a 1959 PDP-1 Computer

Audio is produced on the PDP-1 with a clever hack done by Peter Samson as a student at MIT in the early 1960s. The PDP-1 has six "program flags", which are 6 flip-flops wired to six light bulbs on the control panel. A CPU instruction provides the ability to turn these light bulbs on or off via software. While these bulbs were originally intended to provide program status information to the computer operator, Peter repurposed four of these light bulbs into four square wave generators (or four 1-bit DACs, put another way), by turning the bulbs on and off at audio frequencies. Four wires are attached to the signal lines for these light bulbs. Resistors are used to downmix these four signals into stereo audio channels and provide impedance matching into a standard stereo amplifier, and combined with capacitors to create low pass filters to cut out the buzz of the computer noise and soften the square waves. The four light bulbs act as individual music voices. Each voice is transcribed separately using a custom DSL defined for the 1962 Harmony Compiler, and then merged into a single file which is then compiled by the original Harmony Compiler running on a PDP-1 emulator. The resulting paper tape file is then punched to physical paper tape using a tape punch, and then loaded into the real PDP-1 for music playback.

Samson also contributed to Spacewar!, one of the earliest videogames.

The first place that “do not fold, spindle or mutilate” was taken off the punch card and unpacked in all its metaphorical glory was the student protests at the University of California-Berkeley in the mid-1960s, what became known as the “Free Speech Movement.” The University of California administration used punch cards for class registration. Berkeley protestors used punch cards as a metaphor, both as a symbol of the “system” — first the registration system and then bureaucratic systems more generally — and as a symbol of alienation.

[…]

Because the punch card symbolically represented the power of the university, it made a suitable point of attack. Some students used the punch cards in subversive ways. An underground newspaper reported:

Some ingenious people (where did they get this arcane knowledge? Isn’t this part of the Mysteries belonging to Administration?) got hold of a number of blank IBM cards, and gimmicked the card-puncher till it spoke no mechanical language, but with its little slots wrote on the cards simple letters: “FSM”, “STRIKE” and so on. A symbol, maybe: the rebels are better at making the machine talk sense than its owners. (“Letter from Berkeley” 12; Draper 113)

Students wore these punch cards like name tags. They were thought sufficiently important symbols of the Free Speech Movement that they were used as illustrations on the album cover of the record that the Movement issued.

Another form of technological subversion was for students to punch their own cards, and slip them in along with the official ones: Some joker among the campus eggheads fed a string of obscenities into one of Cal’s biggest and best computers — with the result that the lists of new students in various classes just can NOT be read in mixed company. (Berlandt, “IBM Enrolls” 1)

These pranks were the subversion of the technician. The students were indicating their ability to control the machines, and thus, symbolically, the machinery of the university. But it also indicates, like the students’ and administrations’ shared use of the machine metaphor, something of the degree of convergence of student and administration beliefs and methods. This sort of metaphorical technical subversion rarely rises above the level of prank.

Perhaps more radical, or at least with less confused symbolism, were students who destroyed punch cards in symbolic protest: the punch cards that the university used for class registration stood for all that was wrong with the university, and by extension, America. Students at Berkeley and other University of California branches burned their registration punch cards in anti-University protests just as they burned draft cards in anti-Vietnam protests.