Title:
I/O SYSTEM FOR OFF-LOADING OPERATING SYSTEM FUNCTIONS
Document Type and Number:
WIPO Patent Application WO1988003682
Kind Code:
A1
Abstract:
An I/O processor (22) and memory (12) where a number of queues or linked control blocks (IOCB 1 and IOCB 2) are maintained for each device connected to the I/O processor (22), there is a control block for every operation to be performed by a particular device. A device may be an I/O bus (13a), a controller unit (14) or a peripheral unit (15), the I/O processor (22) maintains a table (46) of different combinations of buses and peripheral controllers that may be used to access a given peripheral unit (15) and selects that combination with the least frequency of use. A portion of main memory (12) is assigned as a single cache so that when the I/O processor (22) accesses a data segment in one of many disk drives (15), the entire disk drive track (59a, b and c) being accessed is read into the assigned cache portion of main memory since following data requests would most likely be made therefrom. The I/O system (13) is provided with a Task Control Processor (21) which provides for the scheduling of the different central processors (10) for the highest priority processes to be run. When an initiate I/O operation is detected, the respective processor (10) is released from the process that it is currently running and can be assigned to the next highest priority process. When requested I/O operation has been completed, the Task Control Processor (13) is signalled so that the Task Control Processor (13) can put the requesting process back into the priority list of processes to be run by the main central processors (10).
Inventors:
PEACOCK RICHARD BROWNING (US)
MURPHY PHILIP ARTHUR (US)
MISSIMER DAVID ROSS (US)
MURPHY PHILIP ARTHUR (US)
MISSIMER DAVID ROSS (US)
Application Number:
PCT/US1987/002812
Publication Date:
May 19, 1988
Filing Date:
October 29, 1987
Export Citation:
Assignee:
UNISYS CORP (US)
International Classes:
G06F13/10; G06F9/46; G06F9/48; G06F13/12; G06F12/08; G06F12/0866; (IPC1-7): G06F9/46
Domestic Patent References:
| WO1987002486A1 | 1987-04-23 |
Foreign References:
| EP0049521A2 | 1982-04-14 | |||
| EP0064142A2 | 1982-11-10 | |||
| US4413317A | 1983-11-01 | |||
| US4435755A | 1984-03-06 | |||
| GB2020456A | 1979-11-14 |
Other References:
See also references of EP 0290533A1
Download PDF: