Punched Card Machines
For almost fifty years, the Hollerith punched card held the majority of the world’s known information and was the primary method of storing, sorting and processing data.
Punching a Card (1928) by Herman Hollerith/International Business Machines Co. Ltd. (IBM)The National Museum of Computing
Introduction
In this story, you will uncover the surprising origin of punched cards and their uses, the events that fuelled the emergence of evolutionary computing technology and explore fascinating machines in The National Museum of Computing’s unique collection.
Punched Card (1890) by Herman HollerithThe National Museum of Computing
The First Punched Cards
In 1804, innovative Frenchman Joseph-Marie Jacquard patented his invention of cards with punched holes which held weaving instructions for the Jacquard Loom. Punched cards automated the process, allowing even unskilled workers to efficiently manufacture intricate patterns.
How did it work?
The location of the holes in the punched cards determines which warp threads (vertical threads attached to the loom) are raised to allow the weft thread (horizontal thread) to pass under them, producing a pattern.
Revolutionary Punched Cards
It was not just the weaving industry this invention revolutionised. Punched cards used binary code (a punched hole, or no hole), a concept that inspired the design of early mechanical computers. The Jacquard Loom is widely regarded as a predecessor to modern computing.
The 'Father of Computing'
During the 1820s, British mathematician and inventor Charles Babbage proposed an ‘Analytical Engine’ that could perform mathematical calculations when fed information using punched cards; it would use a form of many of the components now fundamental to modern computers.
The First Computer Programmer
It was Ada Lovelace, Babbage’s contemporary, who suggested that numbers processed by a computer could represent any kind of data. Ada’s idea illustrates the birth of computer programming. She became a good friend of Babbage after showing a keen interest in his work.
Herman Hollerith's Tabulating Machine (1890) by Herman HollerithThe National Museum of Computing
Punched Cards for Data Processing
The use of punched cards for data processing/storage can be traced back to German-American inventor Herman Hollerith, who sped up and partially mechanised data processing for the 1890 US census (a survey of the population) by using punched cards to record personal information.
The Rising Need for Automation
Manually counting statistics for the 1890 US Census was estimated to take a decade! To find a solution, the government’s Census Bureau launched a competition, from which Herman Hollerith and his Tabulating Machine (able to process 7,000 cards a day) emerged victorious.
Standardised Card Punching
Hollerith founded the Tabulating Machine Company (TMC) which eventually became global technology giant International Business Machines Co Ltd (IBM). In 1928, IBM introduced a standard and widely used punched card format of 80 columns, 12 rows and rectangular holes.
Punching a Card (1928) by Herman Hollerith/International Business Machines Co. Ltd. (IBM)The National Museum of Computing
How Do Holes 'Store' Information?
Data is stored on the card by punching holes, which represent letters or numbers, in specific column locations that relate to the information being recorded. To read this data, the card must be run through a machine that can detect or ‘sense’ the location of the holes.
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The Role of the Punched Card During World War II
Bletchley Park, the home of British codebreaking, is probably best known for housing groundbreaking deciphering machines. Perhaps less well known, is that punched cards were used extensively and in enormous quantities for processing data to aid the codebreaking operation.
The Three Stages of the 'Big' Machine Attacks
Punched cards are considered the first of three machine attacks developed at Bletchley Park, the second was the Bombe (an automated data sorting device to crack the settings of the Enigma machine) and the third was Colossus (the first all-digital semi-programmable computer).
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Mechanical Support for Manual Codebreaking
Bletchley Park used 2 million punched cards a week and housed over 100 associated machines, operated by around 500 staff. This required the construction of ‘Block C’ in November 1942, possibly the largest purpose-built punched card facility in Europe at the time.
How Did Punched Cards Aid the War Effort?
Uses of punched card machines during WWII included: assisting in the creation of Allied codes, completing statistical calculations, analysing encrypted messages (traffic analysis) and searching and sorting decoded messages - all underpinning Bletchley Park’s success.
The Hollerith Electronic Computer (HEC-1)
In 1951, the British Tabulating Machine Co Ltd (BTM) were dominating the British and Commonwealth market for punched card data processing equipment. Based on an initial design by Andrew Booth and adapted by Dr Raymond Bird, the HEC-1 was the first computer to be built by BTM.
Britain’s First Mass-Produced Commercial Computer
HEC-1 was a prototype for Britain’s first mass-produced commercial computer, designed to work with punched card equipment. The subsequent series of computers proved to be very successful. Dr Bird was reunited with the HEC-1 at TNMOC more than 60 years after he constructed it.
Plaque on Powers-Samas Card Punch Unit (Circa 1959) by Powers-SamasThe National Museum of Computing
The Leading British Manufacturer of Punched Card Machines
The rise of automatic punched card equipment stemmed from the need for a efficiently organise facts and transactions for accounting/statistics. The company Powers-Samas became the leading manufacturer of British punched card equipment during the 1950s, employing 5000 people.
Punching
Card punching has four key stages: punching, verifying, sorting and tabulating. In a 1948 Powers-Samas advertisement, the automatic keypunch was referred to as ‘the Rolls Royce of punching machines.’ It aimed to reduce manual operations and simplify the work of punching.
Verifying
The verification process checks that information on the card has been entered correctly. A new operator will repeat the punching operations on the original card using the verifier, which will indicate if the original perforations and the second round of punching do not match.
Sorting
Sorting is used to organise groups of punched cards into a chosen sequence dependent on the data they hold in certain columns. Often, packs of cards will go through multiple sorts, each concerning a different column for classification, until the final desired order is achieved.
Tabulating
James Powers (of Powers-Samas) constructed the first successful printing tabulator in 1913; he believed a machine capable of printing results was essential. The earliest tabulators were only capable of printing figures but demand prompted the development of alphabetical units.
The National Museum of Computing Large Systems Gallery (2021) by The National Museum of ComputingThe National Museum of Computing
Punched Card Machines in the Modern Workplace
Punched card equipment transformed the commercial sector, providing efficient, cost effective and automated solutions to perform the storing, sorting and processing data in the workplace. Explore some large scale computer systems and their associated punched card equipment below.
The ICL (International Computers Limited) CR1000: Mid 1970s
The ICL CR1000 card reader is the pinnacle of technological development for equipment of this kind. Used alongside mainframe machines, it combined compressed air and a vacuum to safely handle cards at high speeds, optically reading 16 cards per second (around 1000 per minute).
The ICL 2966: 1984
TNMOC’s ICL 2966 mainframe was used by TARMAC, a construction company, until 1999. It was the last in a series of ICL machines TARMAC had owned. With the use of punched cards declining from the late 1970s, it was extremely unusual for this machinery to still be in operation.
ICL 2966 Mainframe (1984) by International Computers LimitedThe National Museum of Computing
The ICL 2966 at The National Museum of Computing
The ICL 2966 is the largest computer in TNMOC’s collection - five large cabinets are required just to hold the central processing unit! At the end of its working life, the 2966 was saved by the Computer Conservation Society as it was thought to be the last surviving of its kind.
The IBM (International Business Machines) 1130: 1965
A small yet powerful machine, the IBM 1130 was a data processing facility designed to suit a range of professions. It allowed users to handle substantial amounts of data efficiently. As one of the earliest affordable data processing computers, it proved very popular.
Punched Card Rear Cornering Station (1968) by International Business Machines Co. Ltd. (IBM)The National Museum of Computing
The IBM 1130 at The National Museum of Computing
TNMOC's 1130 was used by Liverpool University's Nuclear Physics Department until 1982. It is one of only five known operational 1130 systems in the world. The IBM 1130 had a card/punch reader used in several IBM computer systems, making this technology accessible to the masses.
Punched Card Rear Cornering Station (1968) by International Business Machines Co. Ltd. (IBM)The National Museum of Computing
Speed and Compatibility
Punched cards are the only method for loading a program onto the machine. Capable of reading 300 cards a minute, then punching at a rate of 80 cards per minute, the IBM 1130 was also compatible with the popular IBM 2501, which could read 600-1000 cards a minute.
The IBM 029: 1964
The IBM 029 was primarily used as a data preparation device, producing 80 column punched cards used to enter data onto machines like the IBM 1130/ICL 2966. Machines like this would fill large rooms where women would work all day punching out data needed for future processing.
A Costly Mistake!
A volunteer and Education Guide at TNMOC recalls spending their college holidays during the 1970s typing data onto punched cards. The rate was £1.00 per hour, with 1 shilling deducted for every mistake made!
Punched Card (1890) by Herman HollerithThe National Museum of Computing
Summary
The history of punched cards is littered with innovation and major computing milestones; they were critical to the success of modern computing's predecessors. Until 2000, punched cards were widely used for inputting and storing data for specialised data processing equipment.
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