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:
Aug. 15, 2000
Filed:
Aug. 25, 1998
Kenta Ninose, Yokohama, JP;
Akira Otsuji, Yokohama, JP;
Yuzuru Maya, Sagamihara, JP;
Hirofumi Nagasuka, Sagamihara, JP;
Taketoshi Sakuraba, Sagamihara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An enqueue structure type is provided within a coupling facility to record the use state and to manage a request queue of resources shared among programs on computers of a system. All programs to use a shared resource issue a request to reserve the shared resource to the coupling facility before using it. The coupling facility affords the permission to use the resource to the programs if it is usable, and adds the programs to the resource request queue if unusable. When a program using the shared resource frees it, the coupling facility fetches a program from the beginning of the request queue, reserves the shared resource for the next program and notifies the next program that the use of the shared resource has been approved. On receiving the notification, the program uses the shared resource without asking the coupling facility for the approval of the use of the shared resource again. Further, exclusive control of shared resources by use of a spin lock having shared and exclusive attributes is implemented by using two locks for one shared resource, wherein the first lock is reserved and then freed after the second lock is reserved.