The front end however treats certain processing control commands as synchronous events, and will await a response from the link before allowing the user to proceed with any other action. When one link completes, either calculations are complete, or another link needs to be run. In the latter case the whole cycle between front end and link is repeated until all calculations are completed. Begin Processing starts the above process. This is a synchronous event in both the front and backend.
Pause causes a pause message to be sent to the presently executing link.
The button will gray-out after it is pressed, as this is a front end synchronous event. This is a backend asynchronous event, and may take a little while before being processed. Pause Next Link is a front-end asynchronous event, and does not send any immediate message to an executing link. The user may toggle this state back and forth while the link is executing in the background. Resume causes a resume message to be sent to the presently loaded, paused link.