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EP0221275A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method and apparatus for ensuring data integrity in a computer system

Assignee: International Business Machines Corp
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Filing: 1986-08-29
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Granted: —
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Expires: 2006-08-29
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Abstract

Abstract A method for ensuring data integrity in a computer system having a primary logical device and one or more alternate logical devices. These logical devices have substantially identical data stored in them and have the capability of responding to requests. The system duplicates device access to the alternate logical devices. The logical devices are identified to the computer system as the devices on which duplicating or mirroring operations are to be performed. A read operation or a write operation is performed on the primary logical device. In the case of a write operation, it is also performed simultaneously on the alternate logical devices. The system waits for a response from the primary logical device. If the response indicates that the primary logical device has failed, the alternate logical devices are relied on to complete the operation.

Inventors

  • 👤 Dennis Jay Foreman
  • 👤 Lawrence Edward Larson

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 19:03
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 92 words
A method of ensuring data integrity of input/output requests in a computer system having a primary logical device and an alternate logical device, both of said devices being capable of responding to a request thereto, the steps comprising: a) identifying both of said logical devices to the computer system as the devices on which mirroring operations are to be performed; b) attempting to perform simultaneously or sub­sequently substantially identical write or read operations on both of said logical devices and c) utilizing the failure free data of one of the logical devices.
Claim 2
Independent Claim 92 words
A method of ensuring data integrity of input/output requests in a computer system having a primary logical device and an alternate logical device, both of said devices being capable of responding to a request thereto, the steps comprising: a) identifying both of said logical devices to the computer system as the devices on which mirroring operations are to be performed; b) attempting to perform simultaneously or sub­sequently substantially identical write or read operations on both of said logical devices and c) utilizing the failure free data of one of the logical devices.
Claim 3
Dependent Claim 31 words
The method in accordance with claim 1, wherein a write or read operation on said second logical device is only performed when the response from the primary device indicates failure thereof.
Claim 4
Dependent Claim 25 words
The method in accordance with claim 1 or 2, wherein indication is given, if the response from both of said logical devices indicate failure thereof.
Claim 5
Independent Claim 27 words
The method in accordance with one of the claims 1 to 3 wherein a user can initiate a mirroring operation at any time during a computer session.
Claim 6
Independent Claim 27 words
The method in accordance with one of the claims 1 to 4 wherein a user can terminate a mirroring operation at any time during a computer session.
Claim 7
Independent Claim 23 words
The method in accordance with one of the claims 1 to 5 wherein both of said logical devices reside on one physical device.
Claim 8
Dependent Claim 29 words
The method in accordance with claim 6 wherein said data residing on one of said logical devices is a portion of the entire data residing on a physical device.
Claim 9
Independent Claim 22 words
The method in accordance with one of the claims 1 to 7 wherein said physical device is a direct access storage device.
Claim 10
Independent Claim 21 words
The method in accordance with one of the claims 1 to 7 wherein said direct access storage device is a printer.
Claim 11
Independent Claim 22 words
The method in accordance with one of the claims 1 to 7 wherein said direct access storage device is a computer terminal.

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