Search in: Word
Vietnamese keyboard: Off
Virtual keyboard: Show
Computing (FOLDOC) dictionary
Simultaneous Peripheral Operation On-Line
Jump to user comments
operating system, history (SPOOL) Accessing peripheral
devices with the help of an off-line tape drive. The term
was derived by IBM for use with the IBM 360 operatingsystems.
In the early days of computing (early 1960s), before
multitasking was invented, computers (e.g. IBM 704) could
run only one job at a time. As peripheral devices such as
printers or card readers were much slower than the CPU,
devoting the computer (the only computer in many cases) to
controlling such devices was impractical.
To free the CPU for useful work, the output was sent to a
magnetic tape drive, which was much faster than a printer
and much cheaper than a computer. After the job was finished
the tape was removed from the tape drive attached to the
computer and mounted on a tape drive connected to a printer
(such as the IBM 1403). The printer could then print the
data without holding up the computer. Similarly, instead of
inputting the program from the card reader it was first copied
to a tape and the tape was read by the computer.