The coordinating interface is refered to both interface between the front processor-schedular and the interface between the programmer-front processor.
The simplest form of coordinating interface may be, just like Java language, an intermediate file, which is generated by the front processor and then interpreted and debuged (?) on the virtual machine, in our case, the system schedular.
A more ambitious design is that the user may have more interactive interface with the overall sys tem. This may includes a programming editing environment, and communications between the environment with the interpreter, the communication manager directively.
Therefor it is possible for more user-freindly dealing with problem like tracing, error reporting or even dynamically user interfer with the system schedular.