Punch cards and when big data meant a full filing cabinet

Matt Nicol

bluenotes contributor

The origin of punch cards for the purposes of “programming” dates back much earlier than most people would likely guess.

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The humble punch card: one of the earliest ways to save a computer program. Illustration: Melissa Currie.

In 1725, Basile Bouchon used punched holes in paper tape to control looms and create more consistent, elaborate weaves.

The idea was further advanced by Herman Hollerith who developed punch card data processing technology for the 1890 US census.

"Often more than a hundred users would share access to a single computer.”

Do not fold, spindle or mutilate

Before the advent of desktop computers, access to computers was both expensive and limited. Often more than a hundred users would share access to a single computer.

Programmers would “save” their programs on a series of punched cards that allowed up to 80 characters per card; though commonly only 72 of those could be used for the actual program.

A single hole would denote a digit and combinations of two or three holes were used for letters and special characters. The more sophisticated machines would provide a translation across the top of the card.

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Easy as 1, 2, 3 … combinations of holes encoded digits, letters and special characters

Writing a program inevitably resulted in large decks of cards - pity the poor programmer who dropped their bundle; it could take hours to resequence a program.

Cards came with the warning “do not fold, spindle or mutilate” as jams in the machine would not only create problems for that program but could damage the card reader.

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ANZ’s Tabulation Section: the Methods Department used punch card machines (South Yarra, 1959)

Technology leads to new, better technology

Due to the sheer volume of transactions being processed, banks (including ANZ) were early adopters of the next iteration of punch cards - data entry machines that captured data onto magnetic tapes.

By the early 1960s ANZ had stopped using punch cards to store permanent data however they were still being used to run some programs into the late 1970s.

You’d be hard pressed to find anyone still employed today with firsthand experience working with punch cards (but do let us know if you’re out there!).

Matt Nicol is a bluenotes contributor

The views and opinions expressed in this communication are those of the author and may not necessarily state or reflect those of ANZ.