Procedure

1. Setup the Simulation:

   • Open the simulation interface in a browser.

2. Configure the Parameters:

   • Set the Number of Processes:
     • Locate the "Number of processes" field in the controls section.
     • Enter the desired number of processes (minimum 3, maximum 20). The default value is 5.
   • Choose the Objective:
     • Open the dropdown menu labeled "Objective."
     • Select one of the available objectives, such as:
       • Just exploring: No specific goal; observe the behavior.
       • Force consensus to run for at least 2 rounds (default).
     • Note that some objectives are locked initially, and can be unlocked by achieving objectives.

3. Run the Simulation:

   • Click the Start simulation button to begin.
   • Observe the consensus process in the display canvas.
   • The same button can be used to pause/resume the simulation.
   • Use the Stop simulation button to stop/reset the simulation.

4. Details of the Simulation:

   • The simulation presents a visual representation of the processes, arranged in a circle.
   • Each process is represented by a colored circle and is initialized with a random value.
   • Over one or more rounds, the processes communicate with each other to reach a consensus.
   • Each round consists of four phases:
     • Phase 1: Each process sends its value to all other processes.
     • Phase 2: Each process finds the minimum value received from other processes.
     • Phase 3: Each process sends the minimum value to all other processes.
     • Phase 4: Each process verifies if the minimum value received from other processes is the same as its own value.
   • If the minimum value received is the same as the process's own value, the process has reached consensus.
   • If not, consensus is not reached, and the process continues to the next round until consensus is reached.
   • Failure to achieve consensus is due to the presence of crash failures in the system.
   • The algorithm is guaranteed to reach consensus in f + 1 rounds, where f is the number of processes that can crash.

5. Crash a Process:

   • To simulate a crash failure, click on a process in the display canvas.
   • The process will be marked as crashed and will not participate in the consensus process.
   • The simulation will continue with the remaining processes.

6. The Game:

   • The goal is to trigger the right processes to crash at the right time to force the consensus algorithm to run for the desired number of rounds.
   • This helps in understanding the behavior of the consensus algorithm in the presence of crash failures.
   • Once the current objective is achieved (and consensus reached), the next objective will be unlocked.

7. Repeat for Additional Objectives:

   • Adjust the number of processes or select a different objective, and restart the simulation to explore various scenarios.