Java™ How to Program, Seventh Edition

1.4. Early Operating Systems

Early computers could perform only one job or task at a time. This is often called single user batch processing. The computer runs a single program at a time while processing data in groups or batches. In these early systems, users generally submitted their jobs to a computer center on decks of punched cards and often had to wait hours or even days before printouts were returned to their desks.

Software systems called operating systems were developed to make using computers more convenient. Early operating systems smoothed and speeded up the transition between jobs, increasing the amount of work, or throughput, computers could process.

As computers became more powerful, it became evident that single-user batch processing ...