提出了以實時多任務系統中的任務鏈為組件，任務鏈運行時間比例作為組件的權重系數，建立實時多任務軟件的可靠性建模方法。該方法符合實時多任務系統應用軟件運行的實時情況，拓展了實時系統可靠性建模的思路，其可靠性模型可以給出單個任務鏈的可靠性參數，且建模方法還可以根據不同任務鏈的重要程度，進行可靠性分配并決定軟件測試和投放時間。
關 鍵 詞 實時系統; 多任務; 任務鏈; 可靠性模型

Abstract Taking lansaction as component in real-time multi-task system, and executeing time rate as the quotiety of lansaction, the paper present a method of reliability modeling based on lansaction for real-time multi-task software. The method tally with the actual situation of programm executing of real-time multi-task. The model can submit evaluation results of single lansaction, so, the reliability modeling is convenient for reliability assigning and determine test time according to importance of the lansaction.
Key words real-time system; multitasking; lansaction; reliability modeling