5 THE COMPUTER BECOMES AN INTERACTIVE TOOL

The computers we have discussed so far were institutional devices, ordered and controlled by organizations rather than individuals. They were pieces of heavy machinery whose cost could be offset only by running large amounts of work through them. Businesses installing computers for electronic data processing followed templates established for punched card machines, using teams of specialist operators to run computers. The managers on whose behalf jobs were run never interacted directly with the computer. Even programmers wrote their code on paper, receiving printed results hours or days later. Scientific computing installations sometimes took another approach, allowing users to sign up for time on computers as with other kinds of specialist lab equipment. This was called open shop operation, versus closed shop, in which the computer remained under the control of specialist operators (a reference to unionized workplaces with rules demarcating which workers could do which types of work). For larger computers, the closed shop model eventually won out, even in scientific centers, as newer technologies such as multiprogramming operating systems and hard disk drives made it even less efficient for programmers or engineers to directly control a computer.