diff --git a/lib/trinity/sim.ex b/lib/trinity/sim.ex
new file mode 100644
index 0000000..2862f67
--- /dev/null
+++ b/lib/trinity/sim.ex
@@ -0,0 +1,15 @@
+defmodule Trinity.Sim do
+  alias Trinity.Scheduler.Simulation
+  import Trinity.Scheduler, only: [simulation_key: 0]
+
+  @spec get_sim :: Simulation.t | nil
+  defp get_sim, do: Process.get(simulation_key())
+
+  @spec simulated? :: boolean
+  def simulated? do
+    case get_sim() do
+      nil -> false
+      _sim -> true
+    end
+  end
+end
diff --git a/lib/trinity/sim_system.ex b/lib/trinity/sim_system.ex
new file mode 100644
index 0000000..dfa6603
--- /dev/null
+++ b/lib/trinity/sim_system.ex
@@ -0,0 +1,20 @@
+defmodule Trinity.SimSystem do
+  alias Trinity.Scheduler.Simulation
+  import Trinity.Scheduler, only: [simulation_key: 0]
+
+  @spec get_sim :: Simulation.t | nil
+  defp get_sim, do: Process.get(simulation_key())
+
+  @spec monotonic_time :: integer
+  def monotonic_time do
+    case get_sim() do
+      nil -> System.monotonic_time()
+      _sim -> sim_monotonic_time()
+    end
+  end
+
+  defp sim_monotonic_time do
+    %{now: now} = get_sim()
+    :atomics.get(now, 1)
+  end
+end