rs: trans btoa (1) : decision_lose_the_frame('Yes') trans atob (1) : decision_lose_the_frame ( Yes' ) Now the only answer to the decision 'Lose the frame' is 'No'. Exhaustive Simulation 233 7.4.4.3 Save and tune the filters To avoid entering again the filters at the next simulation session, we will save them into a file, automatically executed by the model startup file. A. In the Simulator, type the command: list filter >> v76_filter.wri This creates the file v76_filter.wri and inserts the filter commands into it. We will simplify the filters: as the instances of process dispatch, AtoB and BtoA are static, that is, always exist, we can remove the expression is_active before them. B. Open the file v76_filter.wri and remove is_active before dispatch, AtoB and BtoA. The file should now contain: filter length (atob (1) ! queue) > 1 filter length (btoa (1) ! queue) > 1 filter length (dlca!dispatch (1) ! queue) > filter length (dlcb!dispatch (1) ! queue) > 1 filter is_active (dlca!dlc (1) ) and length (dlca!dlc (1) !queue) filter is_active (dlcb!dlc (1) ) and length (dlcb!dlc (1) !queue) filter is_active (dlca!dlc(2), and length (dlca!dlc (2) !queue) filter is active (dlcb!dlc(2) and length (dlcb!dlc (2) !queue) filter create dlca!dlc (3) filter create dlcb!dlc (3) trans btoa (1) : decision_lose_the_frame('Yes' ) trans atob (1) : decision_lose_the_frame(`Yes') C. Open the file v76.startup and add source v76_filter.wri. The file v76.startup should now contain: source v76_feed.wri source start.scn source v76_filter.wri 7.4.4.4 Set the configuration options To get less global states, we will change the default settings of the Simulator. See Chapter 4 for details on Edit > Configuration. A. Select Edit > Configuration and set Reasonable environment to on (box checked) and Loose time progression to off (box not checked). 234 Validation of Communications Systems with SDL 7.4.4.5 Run the exhaustive simulation In case the simulation never terminates, you can stop it by pressing the halt button. A. Type the command verify to st