Punch card technology
In data processing, punch card technology refers to methods of data acquisition, storage and provision using punch cards as data carriers. With its wide range of possible uses, it led to rapid machine-technical development in industrialized countries. The first application was to control the jacquard loom developed in 1805 .
Due to its low working speed compared to the perforated tape and finally because of the development of magnetic data recording , the punch card technology increasingly lost its importance from around 1960.
Overview punch card machines
The technology goes back to the mechanical inventions patented by Herman Hollerith at the end of the 19th century.
Tabulator
The tabulating machine was used to evaluate punch cards. She could add up, so it was of value for statistics, add and subtract, accountants were happy about that, multiply and divide, that pleased the boss, who could write invoices. She had mastered printing since 1920. It became redundant in its function with the advent of electronic data processing in the late 1950s and early 1960s.
Punch card punch
- Data acquisition device for 80-column punch cards
- numeric and alphanumeric keyboard ; Control keyboard
- automatic feed and storage of the punch card
- column-wise punching
- automatic punching possible
- a die block with 12 punches and a sensing station with 24 sensing pins (2 × 12); Punching principle: step transport with subsequent punching process
- Program and constant drum are sensed with 12 star wheels each
Punch card validator
- Data checking device for 80-column punched cards
- checking column by column
- automatic checking possible
- two sensing stations with 24 sensing pins each (2 × 12)
- After the 80th column, a checked, correctly punched card is given a check notch on the right edge of the card
- Defective perforations cause the error lamp to light up
After repeating the checking process for the column in question twice, the punch card receives an error notch on the upper edge of the card if an error is detected. The punch card is scanned by two feeler pens. With each possible sensing process, the sensing pins are mechanically released by the rocker to be ready for sensing.
Punch card sorter
The punch card sorter was used to bring a stack of punch cards into a defined sequence. For example, you could sort numerically by article number or alphabetically by last name. Sorting out, for example to create stacks of punched cards with common features, was also possible.
Punch card mixer
The punch card mixer was used, among other things , to merge two sorted stacks of punch cards that had a common feature. For example, at a telephone company to mix the telephone number on the address file with the telephone number on the stack of the sales register, with the aim of transferring this mixed stack to the tabulation machine for accounting.
Punch card reader
Technical implementation of machine reading
For information extraction two solutions were available.
Electromechanical reading process
The mechanical scanning method originated from Hollerith technology and was accelerated as electromechanical reading from the 1920s .
The information carrier punch card is scanned by scanning brushes. If there is a hole in the information carrier, the sensing brushes close a circuit via the contact surface (contact roller). The resulting impulse is interpreted by the evaluation circuit as a feature of a hole. The electrical contact time of the sensing brush in the hole is shorter than its mechanical contact time with the contact surface (contact roller) - currentless into the hole, currentless out of the hole.
Photoelectric reading process
The information carrier punch card is scanned by bundled light . The light intensity changes are converted into voltage changes by a light-sensitive component . After amplification, the pulses are available for evaluation.
Punch card punch
Output of data in punch cards from the central processing unit ( CPU ) via the buffer memory.
Card track
- Card feed by card feed knife
- The punch card is punched line by line and transported with line 9 first onto the card track (punch track)
- The die block has 80 rectangular punches
- 80-digit sensor brush block for checking the punching tongues
Punching process
The punching unit consists of:
- 80 pairs of punching magnets with one armature each
- 1 impact plate with eccentric
- 80 tie rods
- 80 coupling elements
- 80 punches in the punching die
- 80 return springs
When the punch card punch is ready to function, the striking plate is moved up and down by the eccentric. When a pair of punching magnets is excited, the coupling element is pulled in the direction of the striking plate by the pull rod and is pressed downwards by the coupling element with the punch. The punch card is punched. During the subsequent upward movement of the striking plate, in conjunction with the return spring, it brings about the rest position of the coupling element and punch.
application
A very early industrial use of punch cards can be seen in the textile industry at the beginning of the 19th century. It was there that the French silk weaver Joseph-Marie Jacquard developed the semi-automatic loom, known as the jacquard loom, which - for the first time in 1805 - was controlled with perforated cardboard cards.
The first practical application of punch card technology in public administration took place in the American census of 1890 . Thanks to the use of punch card machines developed by Herman Hollerith , the evaluation of the data could be completed after just one year. (The evaluation of the 1880 census had taken eight years.)
During the First World War , punch cards were used in Germany at the Arms and Ammunition Procurement Office (WUMBA), Haus Cumberland . The punch cards were preserved after the war, the key remained secret, which was used as an argument for use in the 3rd Reich. The naval administration was already using punch cards for billing of fees and material costs at shipyards before 1934.
- The US Army began in World War punchcards logistics in sanitary engineering one.
- Austria-Hungary produced the steel helmet model 1917 at Krupp Berndorfer Metallwarenfabrik . For the statistical validation of the design, Kuk medical reports were evaluated using Hollerith punch card technology .
- In Poland, the IBM subsidiary was called »Polski Hollerith« until 1938, it reported on multitasking and, with the reverse Polish notation, had potential for the development of computers.
- There are reports on the use in the Czech Republic, in Holland and in Belgium in the defense system, i.e. the population statistics .
- In France, the staff officer René Carmille enforced the use of punched card technology for general person registration in the Vichy regime from 1940 , but thwarted the systematic use of the system for the persecution of Jews.
Main article: Machine reporting
After the Second World War it was used in connection with the electronic calculating machines that followed the Zuse Z3 and ENIAC . It is similar to the punched tape used in telex technology .
Over the years the following have been developed:
- as a standalone stand- devices: keypunch , punch cards auditor, punch cards Doppler , hole signature translators , Total Punch
- as peripheral devices of the central unit : punch card reader and punch card punch
bibliography
- Herbert Bruderer: Milestones in computer technology . Volume 1: Mechanical calculating machines, slide rules, historical automatons and scientific instruments, 2nd, strongly exp. Edition, Walter de Gruyter, Berlin / Boston 2018, ISBN 978-3-11-051827-6
- Sebastian Dworatschek: Introduction to data processing . 4th edition, ISBN 978-3-11-168302-7
Web links
- Punch card technology
- Punch card systems - the early days of data processing
- Punch card systems in the US Army
- Columbia University Computing History: IBM Tabulators and Accounting Machines
- Early office museum
- Punch card EDP still working in the museum