Avoiding deadlock situations in a printing system using a locking time-out mechanism
US6631009B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1999 |
| Grant date | Oct 7, 2003 |
| Priority date | — |
| Expiry date | Sep 24, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/524
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A document printing system involves multi-threaded processing of a document object. A deadlock situation between a preprocessing thread and a cancellation thread can be averted with a time-out locking mechanism. After the cancellation thread has locked the document object, its sets a cancel flag, then waits for preprocessing to complete. Meanwhile, the preprocessing thread may request a lock of the document object. If so, it will specify a maximum time-out period. After expiration of the time-out period, a timed-out status response will be sent from the document object to the preprocessing thread. The preprocessing thread will then poll the document object for a cancel flag. A cancel flag will be set on the document object only if the cancellation thread has requested the document object perform a cancellation operation. If there is no cancel flag, the preprocessing thread will again request a lock of the document object with a maximum time-out period. If there is a cancel flag, the preprocessing thread will send a cancellation complete signal to the document object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.