Patent US5287521A successfully refreshed from Google Patents.
US5287521A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for releasing and obtaining shared and exclusive locks
Assignee: Hitachi Ltd
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Filing: 1990-06-12
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Granted: 1994-02-15
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Expires: 2010-06-12
Abstract
Abstract A data processing method is designed to provide two-mode locks of an exclusive mode lock and a shared mode lock in serializing the access to a shared data list being concurrently processed among processes and release the shared mode lock and simultaneously obtain the exclusive mode lock if no process obtains the lock as a result of releasing the process out of the shared mode lock.
Inventors
- 👤 Jun Nitta
- 👤 Shigeru Yoneda
- 👤 Shoji Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:38
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/14; G06F9/00; G06F9/06; G06F9/46; G06F9/52; G06F9/526; G06F2209/00; G06F2209/52; G06F2209/521; G06F2209/523; Y; Y10; Y10S; Y10S707/00; Y10S707/99931; Y10S707/99938
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
172 words
A data processing method for serializing an access to a shared data list being concurrently processed among processes in a data processing device having a lock/unlock feature with a shared mode lock and an exclusive mode lock for serializing access to a data list among concurrently operating processes, in a multiprocessing or multiprogramming environment, said method comprising the steps of: providing a lock word containing an exclusive mode lock flag and a shared mode lock counter, said exclusive mode lock flag being set as a result of decrementing the shared mode lock counter to zero; obtaining the shared mode lock for processes; both, releasing the shared mode lock and simultaneously obtaining the exclusive mode lock, by a single task, if no other process of the processes obtains the lock/unlock feature as a result of releasing said process out of the shared mode lock, and logically deleting a data list element, and actually deleting the data list element when the shared mode lock is released and simultaneously the exclusive mode lock is obtained.
Claim 2
Dependent Claim
172 words
A data processing method for serializing an access to a shared data list being concurrently processed among processes in a data processing device having a lock/unlock feature with a shared mode lock and an exclusive mode lock for serializing access to a data list among concurrently operating processes, in a multiprocessing or multiprogramming environment, said method comprising the steps of: providing a lock word containing an exclusive mode lock flag and a shared mode lock counter, said exclusive mode lock flag being set as a result of decrementing the shared mode lock counter to zero; obtaining the shared mode lock for processes; both, releasing the shared mode lock and simultaneously obtaining the exclusive mode lock, by a single task, if no other process of the processes obtains the lock/unlock feature as a result of releasing said process out of the shared mode lock, and logically deleting a data list element, and actually deleting the data list element when the shared mode lock is released and simultaneously the exclusive mode lock is obtained.
Claim 3
Dependent Claim
20 words
The data processing method according to claim 1, wherein the access to said data list is implemented by queue processing.
References Cited (Backward Citations)
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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) | 1997-02-14 | 1997-08-16 | 1998-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-14 | 2001-08-16 | 2002-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-14 | 2005-08-16 | 2006-02-15 | $7700.00 | Window Closed / Lapsed |