The qemu_edu driver sample includes [tools][eductl_tools] for interacting with the qemu_edu driver. Developers often include binary executables in a Fuchsia package and run those executables as a component for testing and debugging drivers running in a Fuchsia system.

In this driver sample, an executable named eductl_tool provides two options: live and fact. The live command checks for the liveness of the qemu_edu driver in the system. The fact command takes an integer as an additional argument. The value of the integer is passed to the qemu_edu driver to be used as input for computing the factorial. The driver computes the factorial and returns the result to the fact command, which then prints the result on the terminal.

The tasks include:

• Build and run eductl_tool.
• Verify that this tool can interact with the qemu_edu driver.

In VS Code, do the following:

1. Click the TERMINAL tab on the VS Code panel.

2. In the terminal, build and run eductl_tool (and run the live command):

   tools/bazel run //src/qemu_edu/tools:pkg.eductl_tool -- live
   

   This command prints output similar to the following:

   $ tools/bazel run //src/qemu_edu/tools:pkg.eductl_tool -- live
   ...
   INFO: Build completed successfully, 38 total actions
   Running workflow: pkg.eductl_tool_base
   Running task: pkg.debug_symbols_base (step 1/2)
   Running task: pkg.eductl_tool.run_base (step 2/2)
   added repository bazel.pkg.eductl.tool.runnable
   {{ '<strong>' }}Liveness check passed!{{ '</strong>' }}
   

   Verify that the line Liveness check passed! is printed in the end.

3. Run eductl_tool using fact and 12 as input:

   tools/bazel run //src/qemu_edu/tools:pkg.eductl_tool -- fact 12
   

   This command prints output similar to the following:

   $ tools/bazel run //src/qemu_edu/tools:pkg.eductl_tool -- fact 12
   ...
   INFO: Build completed successfully, 1 total action
   Running workflow: pkg.eductl_tool_base
   Running task: pkg.debug_symbols_base (step 1/2)
   Running task: pkg.eductl_tool.run_base (step 2/2)
   added repository bazel.pkg.eductl.tool.runnable
   {{ '<strong>' }}Factorial(12) = 479001600{{ '</strong>' }}
   

   The last line shows that the driver replied 479001600 as the result of the factorial to eductl_tool, which passed 12 as input to the driver.

4. Click the FUCHSIA LOGS tab on the VS Code panel.

5. Click the text box (which already has the filter qemu-edu) and press Enter.

   {: .screenshot}

   Notice that more messages are now logged from the qemu_edu driver.