simultaneous peripheral operations online (SPOOL)

A spooler is a program control system for managing jobs for connected peripherals.

Simultaneous Peripheral Operations Online (SPOOL) is a type of background operation of peripherals, primarily printers, that runs concurrently with other computationally intensive programs. The spool program takes advantage of any pause in the application program to run the jobs that would normally be queued.

A printer spooler manages the print jobs queued in the printer buffer and sends them to the printer. The sequence is based on the FIFO principle, First In First Out (FIFO).