diff --git a/src/main/scala/li/cil/oc/server/component/DebugCard.scala b/src/main/scala/li/cil/oc/server/component/DebugCard.scala
index c0c965246..efa2c27ad 100644
--- a/src/main/scala/li/cil/oc/server/component/DebugCard.scala
+++ b/src/main/scala/li/cil/oc/server/component/DebugCard.scala
@@ -1,6 +1,8 @@
 package li.cil.oc.server.component
 
 import com.google.common.base.Strings
+import cpw.mods.fml.common.Loader
+import cpw.mods.fml.common.ModAPIManager
 import li.cil.oc.OpenComputers
 import li.cil.oc.Settings
 import li.cil.oc.api.Network
@@ -108,6 +110,13 @@ class DebugCard(host: EnvironmentHost) extends prefab.ManagedEnvironment {
     result(new DebugCard.PlayerValue(args.checkString(0)))
   }
 
+  @Callback(doc = """function(name:string):boolean -- Get whether a mod or API is loaded.""")
+  def isModLoaded(context: Context, args: Arguments): Array[AnyRef] = {
+    checkEnabled()
+    val name = args.checkString(0)
+    result(Loader.isModLoaded(name) || ModAPIManager.INSTANCE.hasAPI(name))
+  }
+
   @Callback(doc = """function(command:string):number -- Runs an arbitrary command using a fake player.""")
   def runCommand(context: Context, args: Arguments): Array[AnyRef] = {
     checkEnabled()
diff --git a/src/main/scala/li/cil/oc/server/driver/Registry.scala b/src/main/scala/li/cil/oc/server/driver/Registry.scala
index 811ad3c87..a2f58e0bd 100644
--- a/src/main/scala/li/cil/oc/server/driver/Registry.scala
+++ b/src/main/scala/li/cil/oc/server/driver/Registry.scala
@@ -44,17 +44,26 @@ private[oc] object Registry extends api.detail.DriverAPI {
 
   override def add(driver: api.driver.Block) {
     if (locked) throw new IllegalStateException("Please register all drivers in the init phase.")
-    if (!blocks.contains(driver)) blocks += driver
+    if (!blocks.contains(driver)) {
+      OpenComputers.log.debug(s"Registering block driver ${driver.getClass.getName}.")
+      blocks += driver
+    }
   }
 
   override def add(driver: api.driver.Item) {
     if (locked) throw new IllegalStateException("Please register all drivers in the init phase.")
-    if (!blocks.contains(driver)) items += driver
+    if (!blocks.contains(driver)) {
+      OpenComputers.log.debug(s"Registering item driver ${driver.getClass.getName}.")
+      items += driver
+    }
   }
 
   override def add(converter: Converter) {
     if (locked) throw new IllegalStateException("Please register all converters in the init phase.")
-    if (!converters.contains(converter)) converters += converter
+    if (!converters.contains(converter)) {
+      OpenComputers.log.debug(s"Registering converter ${converter.getClass.getName}.")
+      converters += converter
+    }
   }
 
   override def driverFor(world: World, x: Int, y: Int, z: Int) =