Handles

All resources (files, TCP or UDP connections) are addresses by handles. A handles is a number which is given uniquely to one resource. The numbers are controlled by the user, but have to be from the range:

1..100           file handles
101 …200   TCP handles
201 …300   UDP handles

Example: the command “open 1 text.txt” opens a file for reading. The parameter 1 is the handle. All following operations use the same handle: “close 1” closes the file again. The handle concept is powerful, since parallel operations are possible.