EP0299538A2
Expired / Lapsed
EP
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Unified switching between an invariable and a variable priority task
Assignee: NEC Corp
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Filing: 1988-07-18
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Granted: —
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Expires: 2008-07-18
Abstract
Abstract In a task switching arrangement including a task execution queue (21) having a plurality of priority levels, a queuing and selecting device (29) queues variable priority tasks of a group (17) in a first predetermined level (36) by selecting the predetermined level from the priority levels. When put into execution, one of the variable priority tasks is given a higher priority degree than other variable priority tasks of the group. When this one of the variable priority tasks becomes an interrupted task (31) with its execution interrupted, the queuing and selecting device queues the interrupted task in a second predetermined level (37) selected from the priority levels higher than the first predetermined level. The arrangement can deal with such variable priority tasks of a plurality of groups like invariable priority tasks which are concurrently present in a memory (11) and are queued, when put in an execution waiting state, in selected levels of the priority levels. If the invariable priority tasks include a particular task, the queuing and selecting device queues the particular task in a particular level of the priority levels with the first and the second predetermined levels preferably selected lower and higher than the particular level.
Inventors
- 👤 Yukiko C/O Nec Corporation Mizuhashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 12:11
CPC Classifications
G; G06; G06F; G06F9/00; G06F9/06; G06F9/46; G06F9/48; G06F9/4806; G06F9/4843; G06F9/4881
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
232 words
In a task switching arrangement for use in an information processing system capable of executing a plurality of tasks in a time division fashion, said tasks including a group of variable priority tasks having priority degrees variable with time, said task switching arrangement comprising a task execution queue having a plurality of priority levels and queuing and selecting means coupled to said task execution queue for queuing in selected levels as queued tasks invariable priority tasks having invariable priority degrees and waiting execution with said selected levels selected from said priority levels according to the respective invariable priority degrees and for selecting as a selected task for execution the queued task queued in one of said selected levels that becomes highest of said selected levels, the improvement wherein said queuing and selecting means is for furthermore queuing said group of variable priority tasks in a first predetermined level and an interrupted task in a second predetermined level with said first and second predetermined levels selected from said priority levels lower and higher relative to each other, said interrupted task being one of said variable priority tasks that is in interrupted state, said queuing and selecting means selecting the variable priority tasks of said group collectively as said selected task and said interrupted task as said selected task when said first and said second predetermined levels become higher, respectively, than said selected levels.
Claim 2
Dependent Claim
232 words
In a task switching arrangement for use in an information processing system capable of executing a plurality of tasks in a time division fashion, said tasks including a group of variable priority tasks having priority degrees variable with time, said task switching arrangement comprising a task execution queue having a plurality of priority levels and queuing and selecting means coupled to said task execution queue for queuing in selected levels as queued tasks invariable priority tasks having invariable priority degrees and waiting execution with said selected levels selected from said priority levels according to the respective invariable priority degrees and for selecting as a selected task for execution the queued task queued in one of said selected levels that becomes highest of said selected levels, the improvement wherein said queuing and selecting means is for furthermore queuing said group of variable priority tasks in a first predetermined level and an interrupted task in a second predetermined level with said first and second predetermined levels selected from said priority levels lower and higher relative to each other, said interrupted task being one of said variable priority tasks that is in interrupted state, said queuing and selecting means selecting the variable priority tasks of said group collectively as said selected task and said interrupted task as said selected task when said first and said second predetermined levels become higher, respectively, than said selected levels.
Claim 3
Dependent Claim
41 words
A task switching arrangement as claimed in Claim 1, further comprising scheduling means operatively coupled to said group of variable priority tasks for arranging said variable priority tasks in a descending order of said variable priority degrees from time to time.
Claim 4
Dependent Claim
49 words
A task switching arrangement as claimed in Claim 2, said variable priority tasks of the group having a common priority degree which is invariable with time unless forcibly changed, wherein said queuing and selecting means is for selecting said first predetermined level with reference to said common priority degree.
Claim 5
Dependent Claim
64 words
A task switching arrangement as claimed in Claim 3, wherein: said scheduling means is for forcibly giving said interrupted task a higher priority degree than said common priority degree when said interrupted task is selected as said selected task before put in said interrupted state; said queuing and selecting means being for selecting said second predetermined level with reference to said higher priority degree.
Claim 6
Dependent Claim
93 words
A task switching arrangement as claimed in any of Claims 1 to 4, said plurality of tasks including a particular task having a particular priority degree, wherein said queuing and selecting means is for queuing said particular task in a particular level with said particular level selected from said priority levels according to said particular priority degree, for selecting said first and said second predetermined levels lower and higher than said particular level, and for selecting said particular task as said selected task when said particular level becomes higher than said selected levels.
Claim 7
Dependent Claim
160 words
A task switching arrangement as claimed in any of Claims 1 to 5, said plurality of tasks including a plurality of groups of variable priority tasks having variable priority degrees variable with time, wherein said queuing and selecting means is for queuing each of said groups in a first preselected level with said first preselected level selected from said priority levels and for selecting the variable priority tasks of said each of the groups collectively as said selected task when said first preselected level becomes higher than said selected levels, said queuing and selecting means being for furthermore queuing an interrupted one of the variable priority tasks of said each of the groups in a second preselected level with said second preselected level selected in said priority levels higher than said first preselected level and for selecting said interrupted one of the variable priority tasks as said selected task when said second preselected level becomes higher than said selected levels.
References Cited (Backward Citations)
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