Punched card

Long ago, people used stiff paper cards to store info.

These cards have small holes in them. Machines read where the holes are. This tells the machine what to do.

One man used these cards to count people. He used them for a big census. This is a way to count a whole land. Later, many computers used these cards to work. They were used for many years. Now, we use other ways to save info. It is fun to see how things changed!

A punched card is a stiff piece of paper. It stores digital information using holes. These holes are in set spots on the card.

Long ago, people used these cards for many jobs. In the 1800s, weavers used them to control looms. A loom is a machine that makes cloth. The holes told the machine which threads to lift.

Later, Herman Hollerith used cards to help with the U.S. census. A census is a way to count every person in a country. His machines could read the holes to count data. This helped the government process large amounts of info.

In the 1900s, many big computers used these cards. They used them to store programs and data. People often kept cards in a large stack called a deck.

By the 1960s, magnetic tape began to replace them. Magnetic tape is a different way to save info. Today, we do not use punched cards to store data. But their history helped shape how modern computers work.

A punched card is a stiff piece of paper used to store digital information. It works by using holes in very specific spots. The presence or absence of these holes tells a machine what to do.

For a long time, these cards were the main way to give instructions to computers. They were used to store both data and the programs that run them. Even though we use different tools now, these cards were a huge part of how technology grew. They helped organize information for governments and big businesses all over the world.

How these cards work is quite clever. A machine reads the card by looking at where the holes are located. In some systems, the holes allow levers to move or electrical signals to pass through.

A group of these cards is often called a deck. Each card in the deck might hold a small piece of a larger puzzle. Some cards are called master cards because they hold important starting info. Other cards are called detail cards that provide more specific facts. This step-by-step reading allowed machines to sort and count huge amounts of information very quickly.

The history of these cards began long before modern computers existed. In 1725, Basile Bouchon used paper tape with holes to control a weaving loom. Later, in 1804, Joseph Marie Jacquard made this better with a chain of cards.

These cards told the loom which threads to lift to make patterns. In 1881, Jules Carpentier even used them to record and play music on a harmonium. This showed that holes in paper could represent much more than just patterns for cloth.

In the late 1800s, Herman Hollerith changed everything for data processing. He created a method using punched cards for the 1890 U.S. census.

His machines could read the holes to summarize information. Hollerith started the Tabulating Machine Company, which later became part of IBM. By 1937, IBM was making millions of cards every single day in New York. These cards were so trusted that they were even used for legal documents like government checks.

Even though punched cards are mostly obsolete now, they left a lasting mark. In the 1960s, magnetic tape began to take their place for storing data.

However, the way we use computers today still remembers them. For example, many computer screens still show 80 columns of text. This is a standard that comes directly from the old 80-column punched card format. The legacy of these simple paper cards lives on in the code we write today.

A punched card is a stiff, paper-based medium used to store digital information. It functions through the presence or absence of holes in very specific, predefined positions. These holes act as a code that machines can read to process data or follow instructions.

For much of the 20th century, these cards were essential for data processing and controlling automated machines. They served as the primary method for inputting both computer programs and raw data into early digital computers. Even though they are now obsolete, their influence remains in modern computing standards.

The mechanism of a punched card relies on physical patterns. When a machine reads a card, it detects the holes to determine the information stored there. In some electromechanical systems, holes might allow levers to move or electrical signals to pass through.

A collection of these cards is known as a card deck. Within a deck, certain cards serve specific roles. A master card contains fixed or indicative information for a group. Other cards, called detail cards, provide the specific data points. These cards are often organized into fields, which are sequential columns allocated for specific uses like names or numbers. The small bits of paper removed during the punching process are called chad or chips.

Different formats and types of cards were developed to suit various needs. The IBM 12-row/80-column format became the dominant industry standard. This specific layout provided 80 character positions per line. Some cards featured unique physical markings to help with organization. For example, master cards might have different diagonal corner cuts than detail cards. This allowed machines to separate them automatically during sorting.

Other cards were printed with vertical lines, logos, or field names to make the rows and columns easier for humans to see. Some cards were even used as legal documents, such as U.S. Government checks and savings bonds.

The history of punched card technology spans several centuries and multiple independent inventions. In 1725, Basile Bouchon used paper tape with holes to control a weaving loom. This was later improved by Jean-Baptiste Falcon and Jacques Vaucanson. In 1804, Joseph Marie Jacquard automated loom operation using a chain of linked punched cards. These cards controlled the shedding process, which involves raising and lowering the warp threads. Later, in 1881, Jules Carpentier used a system called the Mélographe Répétiteur to record and play music on a harmonium. He used the Jacquard method to translate musical performances into holes punched in a series of cards.

In the late 19th century, Herman Hollerith revolutionized data processing. He developed a method to record data on cards for the 1890 U.S. census.

His idea was partly inspired by railway punch photographs, where conductors used punches to mark ticket descriptions. Hollerith's tabulating machines could count and summarize data stored on these cards. He founded the Tabulating Machine Company, which eventually became part of IBM in 1924. By 1937, IBM's production was massive, with 32 presses in Endicott, New York, printing between five and 10 million cards every day. During World War II, these machines were used by the Allies to help decrypt Axis communications. At Bletchley Park in England, workers produced approximately 2 million punched cards every week.

The rise of the punched card had significant economic and legal impacts. Large companies like IBM and Remington Rand often tied card purchases to machine leases. This practice led to legal battles, including a 1936 Supreme Court case where the court ruled that IBM could only set card specifications.

By 1950, punched cards were ubiquitous in both government and industry. However, the technology began to change as more capable computers arrived. In the 1950s, the Univac UNITYPER introduced magnetic tape for data entry. Throughout the 1960s, magnetic tape gradually replaced punched cards as the primary storage medium. By the mid-1980s, the combination of affordable magnetic disk storage and interactive terminals made punched cards obsolete for most computing tasks.

Despite being replaced, the legacy of the punched card persists in modern digital environments. One major connection is the 80-character line standard. Many modern command-line interfaces and programming environments still use this convention. This is because early terminals, such as the IBM 3270, displayed 80 columns of text to remain compatible with existing software.

While newer systems use graphical interfaces with variable-width fonts, the structural influence of the 80-column format can still be seen in how data is organized and displayed today.