Device/system for processing shared data accessed by a plurality of data processing devices/systems

• US 5,813,016 A
• Filed: 02/16/1996
• Issued: 09/22/1998
• Est. Priority Date: 03/01/1995
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Sumimoto, Shinji
• Primary Examiner(s): Kulik, Paul V.
• Application Number:
  US08/602,367
• Time in Patent Office: 949 Days
• Field of Search: 395/617, 395/619, 395/712, 395/608, 395/610, 395/474, 395/475, 707/201, 707/203, 707/8, 707/10, 711/147, 711/150, 711/152
• US Class Current: 1/1
• CPC Class Codes: G06F 16/1767 Concurrency control, e.g. optimistic or pessimistic approaches
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

In accessing shared data in a shared storage device from a plurality of systems, the access is prevented from concentrating on one system without the necessity of exclusive control such as a lock mechanism, etc. Predetermined shared data in a network is all updated by a predetermined shared data updating unit in a first data processing device. The update result is written by a version data writing unit to the update storage device. If the predetermined shared data is referred to in the predetermined shared data referring unit in the second data processing device, the referring operation is performed by the predetermined shared data reference control unit on the predetermined shared data of one version prior to the latest version in the shared storage device, thereby requiring no lock mechanism.

Claims

1. A shared data processing device provided in a first data processing device sharing a bus through which data is accessed in one of a shared storage device and an update storage device, and forming at least one of a plurality of data processing devices interconnected through a network, comprising:

first predetermined shared data access control means for accepting a request from another data processing device through the network to update predetermined shared data in the shared storage device or a request generated in the first data processing device to update the predetermined shared data;

predetermined shared data updating means for updating the predetermined shared data in response to the request to update the predetermined shared data accepted by said first predetermined shared data access control means;

version data writing means for writing to the update storage device a version of the predetermined shared data updated by said predetermined shared data updating means;

delayed update means for writing at a predetermined timing a predetermined version of the predetermined shared data stored in the update storage device to a storage position corresponding to the predetermined shared data in the shared storage device;

first update state management means for managing an update state of the predetermined shared data in the update storage device; and

update state notification means for notifying the plurality of data processing devices through the network of the update state of the predetermined shared data in the update storage device managed by said first update state management means.

2. The shared data processing device according to claim 1, wherein

said request to update the predetermined shared data is issued to update system data regulating the structure of a file system other than file data in the file system stored in the shared storage device.

3. The shared data processing device according to claim 1, wherein

said request to update the predetermined shared data is issued to update file data in a file system stored in the shared storage device, or the system data, other than the file data, regulating the structure of a file system.

4. A shared data processing device provided in a second data processing device sharing a bus through which data is accessed in one of a shared storage device and an update storage device, and forming at least one of a plurality of data processing devices interconnected through a network, comprising:

second predetermined shared data access control means for sending a request to update predetermined shared data to a first data processing device through the network when a request generated in the second data processing device to access the shared storage device is the request to update the predetermined shared data, and accepting a request to refer to the predetermined shared data when the request to access the shared storage device is the request to refer to the predetermined shared data;

predetermined shared data referring means for referring to the predetermined shared data in response to the request to refer to the predetermined shared data accepted by said second predetermined shared data access control means;

second update state management means for managing an update state of the predetermined shared data received from said first data processing device through the network and stored in the update storage device; and

predetermined shared data reference control means for issuing from the second data processing device directly through the bus a request to refer to the predetermined shared data, by said predetermined shared data referring means, stored in either the shared storage device or update storage device depending on the update state of the predetermined shared data in the update storage device managed by said second update state management means.

5. A shared data processing system in which a plurality of data processing devices share a bus through which a second data processing device and an update storage device are accessed and are interconnected through a network, comprising:

in a first data processing device forming at least one of the plurality of data processing devices,

first predetermined shared data access control means for accepting a request from another data processing device through the network to update predetermined shared data in the shared storage device or a request generated in the first data processing device to update the predetermined shared data;

predetermined shared data updating means for updating the predetermined shared data in response to the request to update the predetermined shared data accepted by said first predetermined shared data access control means;

version data writing means for writing to the update storage device a version of the predetermined shared data updated by said predetermined shared data updating means;

delayed update means for writing at a predetermined timing a predetermined version of the predetermined shared data stored in the update storage device to a storage position corresponding to the predetermined shared data in the shared storage device;

first update state management means for managing an update state of the predetermined shared data in the update storage device; and

update state notification means for notifying the plurality of data processing devices through the network of the update state of the predetermined shared data in the update storage device managed by said first update state management means, and

in a second data processing device forming at least one of the plurality of data processing devices;

second predetermined shared data access control means for sending a request to update predetermined shared data to the first data processing device through the network when a request generated in the second data processing device to access the shared storage device is the request to update the predetermined shared data, and accepting a request to refer to the predetermined shared data when the request to access the shared storage device, is the request to refer to the predetermined shared data;

predetermined shared data referring means for referring to the predetermined shared data in response to the request to refer to the predetermined shared data accepted by said second predetermined shared data access control means;

second update state management means for managing an update state of the predetermined shared data received from said first data processing device through the network and stored in the update storage device; and

predetermined shared data reference control means for issuing from the second data processing device directly through the bus a request to refer to the predetermined shared data, by said predetermined shared data referring means, stored in either the shared storage device or update storage device depending on the update state of the predetermined shared data in the update storage device managed by said second update state management means.

6. The shared data processing system according to claim 5, wherein

said first data processing device includes all functions of said second data processing device.

7. The shared data processing system according to claim 5 further comprising:

recovery means for restoring the predetermined shared data in the shared storage device to an original state using the predetermined shared data stored in the update storage device when said first data processing device fails.

8. The shared data processing system according to claim 5 further comprising:

version data accessing means for accessing any of a plurality of versions of the predetermined shared data stored in the update storage device.

9. The shared data processing system according to claim 5, wherein

when a plurality of first data processing devices are connected to the network and an active unit of the plurality of first data processing devices fails, another first data processing device takes over a function of controlling the update storage device.

10. The shared data processing system according to claim 5, wherein

said update storage device comprises a ring buffer;

said version data writing means writes the predetermined shared data to the ring buffer, which is the update storage device, only as additional data; and

said delayed update means is activated depending on an amount of the predetermined shared data written to the ring buffer, which is the update storage device.

11. A shared data processing device, coupled via a network to a shared storage device, an update storage device, and a plurality of data processing devices, comprising:

an access control unit to accept a request from one of the data processing devices via the network to update shared data in the shared storage device and a request generated in said shared data processing device to update the shared data;

an update process unit to process the request to update the shared data, accepted by said access control unit;

version update unit to write to the update storage device a first version of the shared data updated by said update unit;

a delayed update unit to write with a predetermined timing, a subset of the shared data stored in the update storage device at a storage position corresponding to the subset of the shared data in the shared storage device;

an update state management unit to manage an update state of the shared data in the update storage device; and

an update state notification unit to notify the data processing devices via the network of the update state of the shared data in the update storage device managed by said update state management unit.