US5845328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for ensuring data coherency for redundat storage by transferring copies of access requests from on-line storage to back-up storage
Assignee: Hitachi Ltd
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Filing: 1996-12-12
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Granted: 1998-12-01
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Expires: 2016-12-12
Abstract
Abstract A command is issued from a processing unit to an on-line storage unit and transferred from the on-line storage unit to a back-up storage unit. The received commands are processed in the respective storage units. An overhead of the on-line storage unit is reduced in a hot stand-by system. Storage contents of the on-line storage unit and the back-up storage unit are made coincident in a structure having a plurality of processing units, where the on-line storage unit and the back-up storage unit are connected through a channel device.
Inventors
- 👤 Yuzuru Maya
- 👤 Soichi Isono
- 👤 Akira Ohtsuji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:58
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2071
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
92 words
In a computer system comprising two storage units having processors, one being an on-line storage unit and the other being a back-up storage unit, and a processing unit for accessing said storage units by issuing commands, a method for making storage contents of two storage units coincident comprising the steps of: issuing a command from said processing unit to said on-line storage unit; transferring the command received by said on-line storage unit to said back-up storage unit; and executing respective processes for the received command in said on-line and back-up storage units.
Claim 2
Dependent Claim
92 words
In a computer system comprising two storage units having processors, one being an on-line storage unit and the other being a back-up storage unit, and a processing unit for accessing said storage units by issuing commands, a method for making storage contents of two storage units coincident comprising the steps of: issuing a command from said processing unit to said on-line storage unit; transferring the command received by said on-line storage unit to said back-up storage unit; and executing respective processes for the received command in said on-line and back-up storage units.
Claim 3
Dependent Claim
38 words
A method for making storage contents of two storage units coincident according to claim 1 wherein said on-line storage unit transmits only a command to update a content of said on-line storage unit to said back-up storage unit.
Claim 4
Dependent Claim
86 words
A method for making storage contents of two storage units coincident according to claim 1 wherein when an execution result of the command by said on-line storage unit indicate normal completion, said on-line storage unit does not compare the execution result by said on-line storage unit with an execution result of the command by said back-up storage unit to said processing unit, and when the execution result of the command by said back-up storage unit indicates memory shortage or fault, the back-up storage unit is reset.
Claim 5
Dependent Claim
111 words
A method for making storage contents of two storage unit coincident according to claim 1 wherein when an execution result of the command by said on-line storage unit indicates normal completion, said on-line storage unit does not compare the execution result of said on-line storage unit with an execution result of the command by said back-up storage unit but transfers the execution result of the command by said on-line storage unit to said processing unit, and when the execution result of the command by said back-up storage unit indicates time-out, said on-line storage unit causes the processing for the command in said back-up storage unit to be executed to the last.
Claim 6
Dependent Claim
35 words
A method for making storage contents of two storage units coincident according to claim 1 wherein said processing unit is connected to said on-line storage unit and said back-up storage unit by a channel device.
Claim 7
Dependent Claim
82 words
A computer system comprising: a first storage unit having a processor working as an on-line storage unit; a second storage unit having another processor working as a back-up storage unit; and a processing unit for accessing said first storage unit by issuing a command thereto; wherein said first storage unit sends said command to said second storage unit and execute a process in accordance with said issued command, and said second storage unit executes a process in accordance with said sent command.
Claim 8
Dependent Claim
82 words
A computer system comprising: a first storage unit having a processor working as an on-line storage unit; a second storage unit having another processor working as a back-up storage unit; and a processing unit for accessing said first storage unit by issuing a command thereto; wherein said first storage unit sends said command to said second storage unit and execute a process in accordance with said issued command, and said second storage unit executes a process in accordance with said sent command.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-30 | 2002-06-01 | 2002-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-30 | 2006-06-01 | 2006-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-30 | 2010-06-01 | 2010-12-01 | $7700.00 | Window Closed / Lapsed |