Data sharing method in a plurality of computer systems

• US 5,978,839 A
• Filed: 05/20/1997
• Issued: 11/02/1999
• Est. Priority Date: 05/21/1996
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Maeda, Shingo, Morishima, Hiroshi, Okuhara, Susumu, Morishima, Kikuko
• Primary Examiner(s): Dinh, Dung C.
• Application Number:
  US08/859,400
• Time in Patent Office: 896 Days
• Field of Search: 395/200.45, 395/200.43, 395/200.44, 395/200.46, 395/726, 395/427, 711/152, 711/153, 711/162, 711/163, 711/147, 711/148, 711/150, 711/202, 710/200, 709/215, 709/213, 709/214, 709/216
• US Class Current: 709/215
• CPC Class Codes: G06F 15/167 using a common memory, e.g. mailbox

Abstract

Processor apparatuses share data, used in common for a plurality of systems, in a global memory in a share system. The global memory is divided into constant units and the individual division units are managed by using identifiers which are definitely determined as viewed from the processor apparatuses and the share system. When an inter-system exclusive state conditioning unit of a processor apparatus designates a desired area on an address space in the processor apparatus by using an identifier to obtain a locked resource, an update state confirming unit checks whether data in a corresponding unit in the share system is updated, and when the data is updated, a data transferring unit transfers the data in the corresponding unit in the share system to the address space. Accordingly, a program operating on each computer system can easily access the data shared by the systems without being aware of the presence of the share system. When the locked resource is released, a data transferring unit transfers the data to the corresponding unit in the share system if the data in the address space is updated.

Claims

1. A data sharing method in which data used in common for processor apparatuses of a plurality of computer systems is shared by a share memory in a share system, comprising the steps of:

dividing said share memory in said share system into constant units and causing said share system to control the length of the individual division units by using identifiers which are definitely determined as viewed from said plurality of computer systems and said share system;

when a processor apparatus designates a desired area on an address space in its computer system by using an identifier to obtain a locked resource, causing said processor apparatus to check whether data in a corresponding unit in said share memory is updated and to transfer data in the corresponding unit in said share memory to said address space when the data is updated; and

when said processor apparatus releases the locked resource, causing said processor apparatus to transfer the data to the corresponding unit in said share memory if said data in said address space is updated.

2. A data sharing method according to claim 1, wherein in said computer system, said processor apparatus accesses a group of a plurality of identifiers and is caused to obtain a locked resource in said share system by using a representative identifier of the identifier group.

3. A data sharing method according to claim 1, wherein in said computer system, the access timing at which said processor apparatus looks-up/updates data on said computer system is made to be asynchronous to the access timing at which said processor apparatus reflects data upon said share system on said computer system.

4. A data sharing system in which data used in common for processor apparatuses of a plurality of computer systems is shared by a share memory in a share system, comprising:

said share system having its share memory divided into constant units, for managing the individual division units by using identifiers which are definitely determined; and

said processor apparatus coupled to said share system and being operative, when designating a desired area on an address space in said computer system by using an identifier to obtain a locked resource, to check whether data in a corresponding unit in said share memory is updated and to transfer the data in the corresponding unit in said share memory to said address space when the data is updated,

wherein when releasing the locked resource, said processor apparatus transfers the data to the corresponding unit in said share memory if the data in said address space is updated.

5. A data sharing system according to claim 4, wherein in said computer system, said processor apparatus accesses a group of a plurality of identifiers and obtains a locked resource in said share system by using a representative identifier of the identifier group.

6. A data sharing system according to claim 4, wherein in said computer system, the access timing at which said processor apparatus looks-up/updates data on said computer system is made to be asynchronous to the access timing at which said processor apparatus reflects data upon said share system on said computer system.