ohjauskortit

Ohjauskortit, also known as control cards, are a type of punch card used in early computing systems for controlling the operation of a computer. They were first introduced in the 1950s and were widely used until the 1970s. Ohjauskortit are rectangular cards made of stiff paper, typically 80 columns wide and 12 rows high, with holes punched in specific patterns to represent data or instructions.

The holes in the ohjauskortit are read by a card reader, which converts the physical presence or absence of holes into binary data that the computer can process. Each column of holes represents a single byte of data, with each row corresponding to a specific bit position within that byte.

Ohjauskortit were used for various purposes, including program storage, data input, and output control. They were particularly useful for batch processing, where multiple jobs could be queued up and processed sequentially by the computer.

The use of ohjauskortit gradually declined with the advent of magnetic tape and disk storage, which offered greater storage capacity and faster access times. However, they played a significant role in the early development of computing and are now considered historical artifacts.