There are many reasons why a simulation execution may be interrupted prematurely or unexpectedly. Your computer crashes. Power goes out in the building. The simulation operator makes a mistake and chooses to stop it. If a simulation is interrupted for any of these reasons, you are usually forced to restart execution from the very beginning. This can be very inconvenient – especially if the simulation is long running or supports a multi-day training exercise.

The FLAMES® Checkpoint/Restart option can keep you from having to start scenario execution over from the beginning if it does not finish as expected. It allows you to restart the execution from a pre-defined point using the data stored in a checkpoint file.

Use FORGE™ to specify the interval at which checkpoint files are going to be created when the scenario is executed. Then, use FIRE™ to execute the scenario. At each checkpoint interval during scenario execution, FLAMES automatically creates a checkpoint file that stores the values of all internal variables within the simulation. The amount of time required to create a checkpoint file is often only a matter of seconds. A distinct checkpoint file is created at each checkpoint interval. Checkpoint files can also be created on demand by a command issued from a FLAMES interactive client application.

Once checkpoint files have been created, FIRE can be restarted using one of the checkpoint files. Based on the information in the file, the values of all the internal variables within the simulation are restored, and scenario execution is resumed exactly as it was executing at the point at which the checkpoint file was created.

When a FLAMES-based simulation is used to support a multi-day training exercise, the use of Checkpoint/Restart is a must. An actual occurrence illustrates why. A FLAMES-based simulation is used regularly to support large training exercises in Europe. During one of these five-day exercises, there was a power failure on day four that shut down several of the computers involved in the exercise, including the computer on which FLAMES was executing. Starting the exercise over again at day one was not an option. Without a way to restart the exercise, the exercise would have been terminated, and literally hundreds of students and training staff involved in the exercise would have been sent home. However, because of the FLAMES Checkpoint/Restart capability, the exercise was restarted shortly after power was restored, and the exercise ran to completion at the end of day five.

Custom software that is developed using the FLAMES Development Suite is automatically compatible with Checkpoint/Restart. This means that all of the internal data in your custom components will automatically be saved in checkpoint files and restored during restart operations.

Note: Checkpoint/Restart is supported on computers running various versions of the Windows operating system. It is not supported on computers running the Linux operating system.


The Checkpoint/Restart option is enabled without a runtime license in FORGE or FIRE if the application is executing with only the bundled components loaded. Therefore, you can try it out using the free copy of the Runtime Suite. If custom component plug-ins are loaded, a runtime license to the Checkpoint/Restart option is required to enable the option. Runtime licenses must be purchased separately. In addition, ALL of the custom component plug-ins loaded by the application must have been developed on computers that were licensed for the Checkpoint/Restart development option.

A Checkpoint/Restart option development license is required in order to create custom component plug-ins using the FLAMES Development Suite that support the option. Development licenses must be purchased separately. As stated above, the functionality of the Checkpoint/Restart option is enabled in an application only if ALL of the component plug-ins loaded by the application were developed on computers that were licensed for the Checkpoint/Restart development option.