The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 02, 1997
Filed:
Jun. 16, 1994
Shigeo Konno, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
Disclosed is an exclusive control method in an I/O subsystem having an exclusive controller which is provided with an exclusive control table and which permits a host interface to use the I/O device when the I/O device is not used by any other host interface while prohibiting the use when another host interface is using the I/O device. The method comprises the steps of: allotting a logical path number to each of the host interfaces of each of the input/output interface portions; Judging whether or not the I/O device is being used by another host interface by reference to the exclusive control table when a request for use of the I/O device is input from a host interface to which a predetermined logical path number is allotted; permitting the host interface which has required for access to use the I/O device when the I/O device is not in use, while setting a flag indicating that the I/O device is 'Occupied' in the exclusive control table in correspondence with the allotted logical path number; and changing the flag to a flag indicating that the I/O device is 'Vacant' when the use of the I/O device is finished.