Punched card input/output

Many early computers, such as the ENIAC, and the IBM NORC, provided for punched card input/output.

[2] Businesses were familiar with storing data on punched cards and keypunch machines were widely employed.

Also file drawers of punched cards served as a low-density offline storage medium for data.

Timing within each read cycle relates the resulting signals to the corresponding position on the card.

For example, the IBM 711 card reader used with the 704/709/7090/7094 series scientific computers treated every row as two 36-bit words, ignoring 8 columns.

The multipunch key is used to produce binary cards, or other characters not on the keypunch keyboard.

Such "lace cards" lacked structural strength, and would frequently buckle and jam inside the machine.