Since each element in a level of decomposition is considered from the blackbox perspective only, the only interactions shown are those between them and the systems actors.
The system context documents how the entire system, represented as a blackbox, interacts with external entities (systems and end users).
系统上下文对表示为黑盒的整个系统如何与外部实体(系统和最终用户)交互做文档说明。
3
The system level "zooms inside" the company blackbox and identifies all employees and systems that collaborate in order to perform the business transaction.