IBM's 1928 rectangular-hole card doubled data density and became computing's standard

By the late 1920s the punched card was the world's medium for data — the census, railroads, utilities and, soon, Social Security all ran on it. Hollerith had sized the card decades earlier to the dimensions of US banknotes so cards fit Treasury Department boxes, and IBM's established machinery read 45 columns of round holes per card. That design was full: one card could hold barely a sentence of information.

Inside IBM two fixes were on the table. Fred Pierce wanted to keep round holes and 45 columns but store more data per column; Clair D. Lake proposed rectangular holes, which could be spaced more tightly and fit 80 columns on the same card — nearly double the capacity. Watson took Lake's route for three reasons: the new card worked with existing tabulator designs, it could be protected by patents, and competitors whose machines sensed round holes mechanically would find the change hard to follow. The card shipped in 1928 with 80 columns; two more rows were added in 1930 for alphabetic coding.

It worked. The IBM card became the industry's standard, later codified as ANSI X3.21 and X3.26, and 80 columns became a unit of computing culture — FORTRAN code still ends at column 72 because that is where a card's identifier field began. Remington Rand answered with a 6-bit code that squeezed 90 columns onto the old 45-column card, integrated it with UNIVAC and in many ways had the better code, but it never escaped UNIVAC's niche. Round-hole cards survived into the early 1990s only in odd corners like turnpike toll tickets.

Rectangular holes pack tighter: 80 columns on the same card

Doubling density without new hardware kept every installed tabulator in play — buyers upgraded their cards, not their machines.

The rectangular hole was patentable, so the new standard legally traced back to one vendor while the market still standardized on it.

Competitors' mechanical hole-sensing equipment was hard to convert, making the format a physical moat as well as a legal one.

Rivals' denser 90-column code rode on legacy cards and stayed locked inside their own computer line — superiority without an ecosystem lost.

A format wins when upgrading costs incumbents nothing and the vendor keeps a protected edge: compatibility buys adoption, a patent buys the rent. Engineer both into one artifact.

The 80-column card carried data processing through the Depression, World War II and the first three decades of electronic computing; IBM's System/360 era still batch-processed on it. ANSI codified the holes (X3.21-1967) and the Hollerith code (X3.26-1980) long after cards were fading, and the 80-column line survives in terminals, code editors and language style guides. Remington Rand's 90-column card is a footnote — the design decision that made adoption inevitable had been made in 1928.