In operating systems, a system call, also known as a systemservicerequest, is the mechanism an application USES to request service from the operating system's kernel.
在操作系统中，系统调用，也称为系统服务请求，是应用程序用来向操作系统内核请求服务的一种机制。
2
When an application calls this service, a service routes the request to the appropriate back-end system.
当应用程序调用此服务时，服务会将请求路由到恰当的后端系统。
3
This enrichment is done within the request flow by calling out to a customer information system, implemented using a Service Invoke primitive.