PERFORATED CARD  What is it? + Formats and Utility ▷ 2020

The progress that computing has made is very great. At the end of the 19th century, punch cards began to appear, which allowed the automation of data by means of special machines. This meant that people no longer had to interfere in the process and the reports issued were more accurate.

Hollerith was one of the first to use these elements to improve the automatic information system, which achieved global acceptance by the public. Even the United States military used these cards to record confidential information.

But these are the only benefits of punch cards. If you want to know how they worked and the different types that were, continue reading this post. We will show you, among other things, what relationship the TPs have with the storage disks that exist today.

What is a punch card and why are they considered the beginning of computers?

A punch card is an element that was used in the year 1890 for the first time to incorporate information into the tabulating machine, created by Herman Hollerith to census the total population of the United States in that year.

It consists of a card with a binary system in which different types of questions with 2 answers or data are included. Being pierced the one that was correct. These sheets were then placed on a container with Mercury and above them were cables that when they found a hole, they recorded the information in the mercury.

In this way the information loading was carried out in an automated way. It is estimated that in this census the information could be processed in only 6 weeks, and the previous calculation was 10 years if this type of machine was not used.

Thus, It is said that the beginning of computing was born here and Hollerith is regarded as the father of computing. Since his invention, some believe, is the first to be able to process data mechanically with the intervention of man the tasks. Although for others Joseph Marie Jacquard was the creator of the automation of information with his loom of 1855. It is also believed that the invention of cards came to light in 1725 by the hand of Basile Bouchon.

What are the main characteristics of a punch card and are they used today?

Currently these perforated cards are not used, since their use was replaced by storage discs such as CD-ROM. Which has a similar method of storing information using binary data. But unsurprisingly, the efficiency of this latest device has no comparison with the old hollowed-out blades.

Now we will see the main characteristics that punch cards had in the past:

  • They were based on binary method, that is, their answers could only be of 2 types.
  • They were organized by columns, which had different places to host the data.
  • Over time, they took different dimensions. Being an important characteristic to differentiate them by manufacturing companies.
  • For the drilling different elements were used, the most modern being special pencils.
  • They did not work if they were not introduced into the machines for which they were designed. That is, if you wanted to change the format for another, this would not work since the machine did not recognize them.

How does a punch card work? Learn to use them

How does a punch card work?  Learn to use them

The cards were made of cardboard or some sturdy material that had different types of holes. They could be circular, oval, or rectangular. These gaps were known as “Chads” or Chips, the latest imposed by IBM.

If they put all the cards together, taking as reference the corners that, in general, tThey sent certain clippings to establish whether or not they belonged to the group of these, called a “deck”. This mallet was the one that was put into the drilling machine in order to process the data.

Next to the chads were placed “Fields”. This was multi-character data that could include words or large numbers, laid out in columns adjacent to the card. After the card has been used, usually kept in different places or destroyed to avoid duplicating data. Since there was no way to identify those that had already been processed.

Formats and types of punch cards What are all that exist?

Punch cards they became very popular during a little over the first half of the 20th century. This was due to the practicality they presented and the efficiency they had in issuing the reports. There were different types of cards, but it was not until 1928 that they began to be standardized, thus generating a general purpose for all of them.

We present below the different formats and types of sheets that existed in history.

Hollerith Pierced

They were the first that made people take an interest in this type of technique. It was developed in 1890 by Herman Hollerith to carry out the census of that year to the more than 62 million people that existed in the United States.

Its measurements were 9 x 21.5 centimeters and they were pierced by circles. The first ones contained 20 columns, but later that number was increased to 45. A curiosity that characterized these plates is that they were the same size of a dollar that existed at that time.

90-character perforated UNIVAC

90-character perforated UNIVAC

It was developed by the company Remington-Rand UNIVAC 2 characters were available for each of the 45 columns. While each of these had 12 places to drill circularly.

Perforated 80-column IBM

It is the first card that changes the round hole for a rectangular one. It was launched in 1928 by IBM and had 80 columns of one character for each of these with 12 places for drilling.

Its measurements were 18.73 x 8.25 cm. They were 0.179 mm thick. They had 12 positions distributed 10 in the lower part, which represented each of the digits, while the upper 2 were called “Drilling Zone 12” Y “Drilling Zone 11”. These two areas were used for addition and subtraction respectively.

In 1964, IBM made important changes to the code entry method. Capital letters and characters began to be combined to represent letters and other necessary combinations. This made it possible to make up to 6 perforations per column. In addition, the design of the corners was changed to round ones.

This type of card was widely accepted by users, granting the generic name of “IBM Cards” to all those that existed in the market at that time.

Mark sense

These types of plates had a oval perforation and were designed by the father of the hard drive, Reynold B. Johnson, an IBM employee. They had the peculiarity that an electrographic pencil was needed to make the holes and they could incorporate additional information to better represent the data that would be perforated with the ovals.


It was created in 1943 and they were used for diagrams in whatever discipline is necessary engineering. The perforations are made on the right side of the card through a sliced ​​hole, which contained 35mm film with a microform image, the one that was mounted in the hole.

He had his success in the United States Navy and in all the armed forces of that country. At the beginning of 1957 its use was popular in all North American government agencies.

51 column IBM

This sheet is an evolution of the punch card of 80 IBM columns. Although it has the same operation, the number of columns was restricted to 51, so that these were used by other types of users with lower requirements.

In this way it became popular in those small businesses that needed to record sales and inventories from a market with minor operations.

If you have any questions, leave them in the comments, we will answer you as soon as possible, and it will also be of great help to more members of the community. Thank you! 😉

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