An I/O device control subsystem for controlling issuance of commands to one I/O device while it is doing I/O device to I/O device data transfers with another I/O device. The I/O device control subsystem has a timer for indicating current time. The time required to write the transferred data, known at...http://www.google.com.au/patents/US4517641?utm_source=gb-gplus-sharePatent US4517641 - Lookahead I/O device control subsystem
