Kinds of operating systems (2)
Concurrent I/O and programs
SPOOL-ing (Simultaneous Peripheral Operation On Line)
Allows direct input & output
Multiple programs resident in memory at once
Keeps processor busy
On-line file storage
Some support for terminals, telecommunications
Early business computers
E.g., IBM 7070, IBM 360 & 370
Scientific computing
E.g., Control Data 6600, IBM 360/91