Every now and then, my brain clamps on to obscure trivia like this. It takes so much time. “Because the paper beds of banknote presses in 1860 were 14.5 inches by 16.5 inches, a movie industry cartel set a standard for theater projectors based on silent film, and two kilobytes is two kilobytes” is as far back as I have been able to push this, but let’s get started.

In August of 1861, by order of the U.S. Congress and in order to fund the Union’s ongoing war efforts against the treasonous secessionists of the South, the American Banknote Company started printing what were then called “Demand Notes”, but soon widely known as “greenbacks”.

It’s difficult to research anything about the early days of American currency on Wikipedia these days; that space has been thoroughly colonized by the goldbug/sovcit cranks. You wouldn’t notice it from a casual examination, which is of course the plan; that festering rathole is tucked away down in the references, where articles will fold a seemingly innocuous line somewhere into the middle, tagged with an exceptionally dodgy reference. You’ll learn that “the shift from demand notes to treasury notes meant they could no longer be redeemed for gold coins[1]” – which is strictly true! – but if you chase down that footnote you wind up somewhere with a name like “Lincoln’s Treason – Fiat Currency, Maritime Law And The U.S. Treasury’s Conspiracy To Enslave America”, which I promise I am only barely exaggerating about.

It’s not entirely clear if this is a deliberate exercise in coordinated crank-wank or just years of accumulated flotsam from the usual debate-club dead-enders hanging off the starboard side of the Overton window. There’s plenty of idiots out there that aren’t quite useful enough to work the k-cups at the Heritage Institute, and I guess they’re doing something with their time, but the whole thing has a certain sinister elegance to it that the Randroid crowd can’t usually muster. I’ve got my doubts either way, and I honestly don’t care to dive deep enough into that sewer to settle them. Either way, it’s always good to be reminded that the goldbug/randroid/sovcit crank spectrum shares a common ideological klancestor.

Mercifully that is not what I’m here for. I am here because these first Demand Notes, and the Treasury Notes that came afterwards, were – on average, these were imprecise times – 7-3/8” wide by 3-1/4” tall.

I haven’t been able to precisely answer the “why” of that – I believe, but do not know, that that this is because of the size of the specific dimensions of the presses they were printed on. Despite my best efforts I haven’t been able to find the exact model and specifications of that device. I’ve asked the U.S. Congressional Research Service for some help with this, but between them and the Bureau of Engraving and Printing, we haven’t been able to pin it down. From my last correspondence with them:

Unfortunately, we don’t have any materials in the collection identifying the specific presses and their dimension for early currency production. The best we can say is that the presses used to print currency in the 1860s varied in size and model. These presses went by a number of names, including hand presses, flat-bed presses, and spider presses. They also were capable of printing sheets of paper in various sizes. However, the standard size for printing securities and banknotes appears to have been 14.5 inches by 16.5 inches. We hope this bit of information helps.

… which is unfortunate, but it does give us some clarity. A 16.5″ by 14.5″ printing sheet lets you print eight 7-3/8” by 3-1/4″ sheets to size, with a fraction of an inch on either side for trimming.

The answer to that question starts to matter about twenty years later on the heels of the 1880 American Census. Mandated to be performed once a decade, the United States population had grown some 30% since the previous census, and even with enormous effort the final tabulations weren’t finished until 1888, an unacceptable delay.

One of the 1880 Census’ early employees was a man named Herman Hollerith, a recent graduate of the Columbia School of Mines who’d been invited to join the Census efforts early on by one of his professors. The Census was one of the most important social and professional networking exercises of the day, and Hollerith correctly jumped at the opportunity:

The absence of a permanent institution meant the network of individuals with professional census expertise scattered widely after each census. The invitation offered a young graduate the possibility to get acquainted with various members of the network, which was soon to be dispersed across the country.

As an aside, that invitation letter is one of the most important early documents in the history of computing for lots of reasons, including this one:

The machine in that picture was the third generation of the “Hollerith Tabulator”, notable for the replaceable plugboard that made it reprogrammable. I need to find some time to dig further into this, but that might be the first multipurpose, if not “general purpose” as we’ve come to understand it, electronic computation device. This is another piece of formative tech that emerged from this era, one that led to directly to the removable panels (and ultimately the general componentization) of later computing hardware.

Well before the model 3, though, was the original 1890 Hollerith Census Tabulator that relied on punchcards much like this one.

Hollerith took the inspiration for those punchcards from the “punch photographs” used by some railways at the time to make sure that tickets belonged to the passengers holding them. You can see a description of one patent for them here dating to 1888, but Hollerith relates the story from a few years earlier:

One thing that helped me along in this matter was that some time before I was traveling in the west and I had a ticket with what I think was called a punch photograph. When the ticket was first presented to a conductor he punched out a description of the individual, as light hair, dark eyes, large nose etc. So you see I only made a punch photograph of each person.

Tangentially: this is the birth of computational biometrics. And as you can see from this extract from The Railway News (Vol. XLVIII, No. 1234 , published Aug. 27, 1887) people have been concerned about harassment because of unfair assessment by the authorities from day one:

After experimenting with a variety of card sizes Hollerith decided that to save on production costs he’d use the same boxes the U.S. Treasury was using for the currency of the day: the Demand Note. Punch cards stayed about that shape, punched with devices that looked a lot like this for about 20 years until Thomas Watson Sr. (IBM’s first CEO, from whom the Watson computer gets its name) asked Clair D. Lake and J. Royden Peirce to develop a new, higher data-density card format.

Tragically, this is the part where I need to admit an unfounded assertion. I’ve got data, the pictures line up and numbers work, but I don’t have a citation. I wish I did.

Take a look at “Type Design For Typewriters: Olivetti, written by Maria Ramos Silvia. (You can see a historical talk from her on the history of typefaces here that’s also pretty great.)

Specifically, take a look on page 46 at Mikron Piccolo, Mikron Condensed. The fonts don’t precisely line up – see the different “4”, for example, when comparing it to the typesetting of IBM’s cards – but the size and spacing do. In short: a line of 80 characters, each separated by a space, is the largest round number of digits that the tightest typesetting of the day would allow to be fit on a single 7-3/8” wide card: a 20-point condensed font.

I can’t find a direct citation for this; that’s the only disconnect here. But the spacing all fits, the numbers all work, and I’d bet real money on this: that when Watson gave Lake the task of coming up with a higher information-density punch card, Lake looked around at what they already had on the shelf – a typewriter with the highest-available character density of the day, on cards they could manage with existing and widely-available tooling – and put it all together in 1928. The fact that a square hole – a radical departure from the standard circular punch – was a patentable innovation at the time was just icing on the cake.

The result of that work is something you’ll certainly recognize, the standard IBM punchcard, though of course there’s lot more to it than that. Witness the full glory of the Card Stock Acceptance Procedure, the protocol for measuring folding endurance, air resistance, smoothness and evaluating the ash content, moisture content and pH of the paper, among many other things.

At one point sales of punchcards and related tooling constituted a completely bonkers 30% of IBM’s annual profit margin, so you can understand that IBM had a lot invested in getting that consistently, precisely correct.

At around this time John Logie Baird invented the first “mechanical television”; like punchcards, the first television cameras were hand-cranked devices that relied on something called a Nipkow disk, a mechanical tool for separating images into sequential scan lines, a technique that survives in electronic form to this day. By linearizing the image signal Baird could transmit the image’s brightness levels via a simple radio signal and in 1926 he did just that, replaying that mechanically encoded signal through a CRT and becoming the inventor of broadcast television. He would go on to pioneer colour television – originally called Telechrome, a fantastic name I’m sad we didn’t keep – but that’s a different story.

Baird’s original “Televisor” showed its images on a 7:3 aspect ration vertically oriented cathode ray tube, intended to fit the head and shoulders of a standing person, but that wouldn’t last.

For years previously, silent films had been shot on standard 35MM stock, but the addition of a physical audio track to 35MM film stock didn’t leave enough space left over for the visual area. So – after years of every movie studio having its own preferred aspect ratio, which required its own cameras, projectors, film stock and tools (and and and) – in 1929 the movie industry agreed to settle on the Society of Motion Picture And Television Engineers’ proposed standard of 0.8 inches by 0.6 inches, what became known as the Academy Ratio, or as we better know it today, 4:3.

Between 1932 and 1952, when widescreen for cinemas came into vogue as a differentiator from standard television, just about all the movies made in the world were shot in that aspect ratio, and just about every cathode ray tube made came in that shape, or one that could display it reliably. In 1953 studios started switching to a wider “Cinemascope”, to aggressively differentiate themselves from television, but by then television already had a large, thoroughly entrenched install base, and 4:3 remained the standard for in-home displays – and CRT manufacturers – until widescreen digital television came to market in the 1990s.

As computers moved from teleprinters – like, physical, ink-on-paper line printers – to screens, one byproduct of that standardization was that if you wanted to build a terminal, you either used that aspect ratio or you started making your own custom CRTs, a huge barrier to market entry. You can do that if you’re IBM, and you’re deeply reluctant to if you’re anyone else. So when DEC introduced their VT52 terminal, a successor to the VT50 and earlier VT05 that’s what they shipped, and with only 1Kb of display ram (one kilobyte!) it displayed only twelve rows of widely-spaced text. Math is unforgiving, and 80×12=960; even one more row breaks the bank. The VT52 and its successor the VT100, though, doubled that capacity giving users the opulent luxury of two entire kilobytes of display memory, laid out with a font that fit nicely on that 4:3 screen. The VT100 hit the market in August of 1978, and DEC sold more than six million of them over the product’s lifespan.

You even got an extra whole line to spare! Thanks to the magic of basic arithmetic 80×25 just sneaks under that opulent 2k limit with 48 bytes to spare.

This is another point where direct connections get blurry, because 1976 to 1984 was an incredibly fertile time in the history of computing history. After a brief period where competing terminal standards effectively locked software to the hardware that it shipped on, the VT100 – being the first terminal to market fully supporting the recently codified ANSI standard control and escape sequences – quickly became the de-facto standard, and soon afterwards the de-jure, codified in ANSI-X3.64/ECMA-48. CP/M, soon to be replaced with PC-DOS and then MS-DOS came from this era, with ANSI.SYS being the way DOS programs talked to the display from DOS 2.0 through to beginning of Windows. Then in 1983 the Apple IIe was introduced, the first Apple computer to natively support an 80×24 text display, doubling the 40×24 default of their earlier hardware . The original XTerm, first released in 1984, was also created explicitly for VT100 compatibility.

Fascinatingly, the early versions of the ECMA-48 standard specify that this standard isn’t solely meant for displays, specifying that “examples of devices conforming to this concept are: an alpha-numeric display device, a printer or a microfilm output device.”

A microfilm output device! This exercise dates to a time when microfilm output was a design constraint! I did not anticipate that cold-war spy-novel flavor while I was dredging this out, but it’s there and it’s magnificent.

It also dates to a time that the market was shifting quickly from mainframes and minicomputers to microcomputers – or, as we call them today, “computers” – as reasonably affordable desktop machines that humans might possibly afford and that companies might own a large number of, meaning this is also where the spectre of backcompat starts haunting the industry – This moment in a talk from the Microsoft developers working on the Windows Subsystem for Linux gives you a sense of the scale of that burden even today. In fact, it wasn’t until the fifth edition of ECMA-48 was published in 1991, more than a decade after the VT100 hit the market, that the formal specification for terminal behavior even admitted the possibility (Appendix F) that a terminal could be resized at all, meaning that the existing defaults were effectively graven in stone during what was otherwise one of the most fertile and formative periods in the history of computing.

As a personal aside, my two great frustrations with doing any kind of historical CS research remain the incalculable damage that academic paywalls have done to the historical record, and the relentless insistence this industry has on justifying rather than interrogating the status quo. This is how you end up on Stack Overflow spouting unresearched nonsense about how “4 pixel wide fonts are untidy-looking”. I’ve said this before, and I’ll say it again: whatever we think about ourselves as programmers and these towering logic-engines we’ve erected, we’re a lot more superstitious than we realize, and by telling and retelling these unsourced, inaccurate just-so stories without ever doing the work of finding the real truth, we’re betraying ourselves, our history and our future. But it’s pretty goddamned difficult to convince people that they should actually look things up instead of making up nonsense when actually looking things up, even for a seemingly simple question like this one, can cost somebody on the outside edge of an academic paywall hundreds or thousands of dollars.

So, as is now the usual in these things:

There are technical reasons,

There are social reasons,

It’s complicated, and

Open access publication or GTFO.

But if you ever wondered why just about every terminal in the world is eighty characters wide and twenty-five characters tall, there you go.