Hmm, this might make more sense. Maybe.

src/main/java/li/cil/oc/api/Driver.java

@@ -100,10 +100,10 @@ public final class Driver {
      * will be used.
      *
      * @param stack the item stack to get a driver for.
-     * @param host  the object that will host the environment created by returned driver.
+     * @param host  the type that will host the environment created by returned driver.
      * @return a driver for the item, or <tt>null</tt> if there is none.
      */
-    public static Item driverFor(ItemStack stack, EnvironmentHost host) {
+    public static Item driverFor(ItemStack stack, Class<? extends EnvironmentHost> host) {
         if (instance != null)
             return instance.driverFor(stack, host);
         return null;

src/main/java/li/cil/oc/api/detail/DriverAPI.java

@@ -73,10 +73,10 @@ public interface DriverAPI {
      * will be used.
      *
      * @param stack the item stack to get a driver for.
-     * @param host  the object that will host the environment created by returned driver.
+     * @param host  the type that will host the environment created by returned driver.
      * @return a driver for the item, or <tt>null</tt> if there is none.
      */
-    Item driverFor(ItemStack stack, EnvironmentHost host);
+    Item driverFor(ItemStack stack, Class<? extends EnvironmentHost> host);
 
     /**
      * Looks up a driver for the specified item stack.

src/main/java/li/cil/oc/api/driver/Item.java

@@ -32,10 +32,10 @@ public interface Item {
      * be ejected, since this value is only checked when adding components.
      *
      * @param stack the item to check.
-     * @param host  the host the environment would live in.
+     * @param host  the type of host the environment would live in.
      * @return <tt>true</tt> if the item is supported; <tt>false</tt> otherwise.
      */
-    boolean worksWith(ItemStack stack, EnvironmentHost host);
+    boolean worksWith(ItemStack stack, Class<? extends EnvironmentHost> host);
 
     /**
      * Used to determine the item types this driver handles.

src/main/java/li/cil/oc/api/prefab/DriverItem.java

@@ -27,7 +27,12 @@ public abstract class DriverItem implements li.cil.oc.api.driver.Item {
     }
 
     @Override
-    public boolean worksWith(final ItemStack stack, final EnvironmentHost host) {
+    public boolean worksWith(final ItemStack stack, final Class<? extends EnvironmentHost> host) {
+        return worksWith(stack);
+    }
+
+    @Override
+    public boolean worksWith(final ItemStack stack) {
         if (stack != null) {
             for (ItemStack item : items) {
                 if (item != null && item.isItemEqual(stack)) {

src/main/scala/li/cil/oc/client/gui/Robot.scala

@@ -23,7 +23,7 @@ class Robot(playerInventory: InventoryPlayer, val robot: tileentity.Robot) exten
     case Some(buffer: api.component.TextBuffer) => buffer
   }.headOption.orNull
 
-  override protected val hasKeyboard = robot.info.components.map(api.Driver.driverFor).contains(driver.item.Keyboard)
+  override protected val hasKeyboard = robot.info.components.map(api.Driver.driverFor(_, robot.getClass)).contains(driver.item.Keyboard)
 
   private val withScreenHeight = 256
   private val noScreenHeight = 108

src/main/scala/li/cil/oc/common/component/Terminal.scala

@@ -15,7 +15,7 @@ import scala.collection.mutable
 class Terminal(val rack: tileentity.ServerRack, val number: Int) {
   val buffer = {
     val screenItem = api.Items.get("screen1").createItemStack(1)
-    val buffer = api.Driver.driverFor(screenItem, rack).createEnvironment(screenItem, rack).asInstanceOf[api.component.TextBuffer]
+    val buffer = api.Driver.driverFor(screenItem, rack.getClass).createEnvironment(screenItem, rack).asInstanceOf[api.component.TextBuffer]
     val (maxWidth, maxHeight) = Settings.screenResolutionsByTier(1)
     buffer.setMaximumResolution(maxWidth, maxHeight)
     buffer.setMaximumColorDepth(Settings.screenDepthsByTier(1))
@@ -24,7 +24,7 @@ class Terminal(val rack: tileentity.ServerRack, val number: Int) {
 
   val keyboard = {
     val keyboardItem = api.Items.get("keyboard").createItemStack(1)
-    val keyboard = api.Driver.driverFor(keyboardItem, rack).createEnvironment(keyboardItem, rack).asInstanceOf[api.component.Keyboard]
+    val keyboard = api.Driver.driverFor(keyboardItem, rack.getClass).createEnvironment(keyboardItem, rack).asInstanceOf[api.component.Keyboard]
     keyboard.setUsableOverride(new UsabilityChecker {
       override def isUsableByPlayer(keyboard: api.component.Keyboard, player: EntityPlayer) = {
         val stack = player.getCurrentEquippedItem

src/main/scala/li/cil/oc/common/inventory/ComponentInventory.scala

@@ -35,7 +35,7 @@ trait ComponentInventory extends Inventory with network.Environment {
     for (slot <- 0 until getSizeInventory if slot >= 0 && slot < components.length) {
       val stack = getStackInSlot(slot)
       if (stack != null && components(slot).isEmpty && isComponentSlot(slot)) {
-        components(slot) = Option(Driver.driverFor(stack, host)) match {
+        components(slot) = Option(Driver.driverFor(stack, host.getClass)) match {
           case Some(driver) =>
             Option(driver.createEnvironment(stack, host)) match {
               case Some(component) =>
@@ -81,7 +81,7 @@ trait ComponentInventory extends Inventory with network.Environment {
         components(slot) match {
           case Some(component) =>
             // We're guaranteed to have a driver for entries.
-            save(component, Driver.driverFor(stack, host), stack)
+            save(component, Driver.driverFor(stack, host.getClass), stack)
           case _ => // Nothing special to save.
         }
       }
@@ -93,7 +93,7 @@ trait ComponentInventory extends Inventory with network.Environment {
   override def getInventoryStackLimit = 1
 
   override protected def onItemAdded(slot: Int, stack: ItemStack) = if (isComponentSlot(slot)) {
-    Option(Driver.driverFor(stack, host)).foreach(driver =>
+    Option(Driver.driverFor(stack, host.getClass)).foreach(driver =>
       Option(driver.createEnvironment(stack, host)) match {
         case Some(component) => this.synchronized {
           components(slot) = Some(component)
@@ -124,7 +124,7 @@ trait ComponentInventory extends Inventory with network.Environment {
         components(slot) = None
         updatingComponents -= component
         Option(component.node).foreach(_.remove())
-        Option(Driver.driverFor(stack, host)).foreach(save(component, _, stack))
+        Option(Driver.driverFor(stack, host.getClass)).foreach(save(component, _, stack))
         // However, nodes then may add themselves to a network again, to
         // ensure they have an address that gets sent to the client, used
         // for associating some components with each other. So we do it again.

src/main/scala/li/cil/oc/common/inventory/ServerInventory.scala

@@ -1,7 +1,7 @@
 package li.cil.oc.common.inventory
 
 import li.cil.oc.api.Driver
-import li.cil.oc.common.InventorySlots
+import li.cil.oc.common.{InventorySlots, tileentity}
 import net.minecraft.entity.player.EntityPlayer
 import net.minecraft.item.ItemStack
 
@@ -17,7 +17,7 @@ trait ServerInventory extends ItemStackInventory {
   override def isUseableByPlayer(player: EntityPlayer) = false
 
   override def isItemValidForSlot(slot: Int, stack: ItemStack) =
-    Option(Driver.driverFor(stack)).fold(false)(driver => {
+    Option(Driver.driverFor(stack, classOf[tileentity.ServerRack])).fold(false)(driver => {
       val provided = InventorySlots.server(tier)(slot)
       driver.slot(stack) == provided.slot && driver.tier(stack) <= provided.tier
     })

src/main/scala/li/cil/oc/common/item/Tablet.scala

@@ -221,7 +221,7 @@ class TabletWrapper(var stack: ItemStack, var holder: EntityPlayer) extends Comp
 
   override def cpuArchitecture: Class[_ <: Architecture] = {
     for (i <- 0 until getSizeInventory if isComponentSlot(i)) Option(getStackInSlot(i)) match {
-      case Some(s) => Option(Driver.driverFor(s, host)) match {
+      case Some(s) => Option(Driver.driverFor(s, getClass)) match {
         case Some(driver: Processor) if driver.slot(s) == Slot.CPU => return driver.architecture(s)
         case _ =>
       }
@@ -231,7 +231,7 @@ class TabletWrapper(var stack: ItemStack, var holder: EntityPlayer) extends Comp
   }
 
   override def installedMemory = items.foldLeft(0)((acc, itemOption) => acc + (itemOption match {
-    case Some(item) => Option(api.Driver.driverFor(item, host)) match {
+    case Some(item) => Option(api.Driver.driverFor(item, getClass)) match {
       case Some(driver: api.driver.Memory) => driver.amount(item)
       case _ => 0
     }

src/main/scala/li/cil/oc/common/template/RobotTemplate.scala

@@ -1,7 +1,7 @@
 package li.cil.oc.common.template
 
 import cpw.mods.fml.common.event.FMLInterModComms
-import li.cil.oc.common.{Slot, Tier}
+import li.cil.oc.common.{Slot, Tier, tileentity}
 import li.cil.oc.util.ExtendedNBT._
 import li.cil.oc.util.ItemUtils
 import li.cil.oc.{Settings, api}
@@ -10,6 +10,8 @@ import net.minecraft.item.ItemStack
 import net.minecraft.nbt.{NBTTagCompound, NBTTagList}
 
 object RobotTemplate extends Template {
+  override protected def hostClass = classOf[tileentity.Robot]
+
   def selectTier1(stack: ItemStack) = ItemUtils.caseTier(stack) == Tier.One
 
   def selectTier2(stack: ItemStack) = ItemUtils.caseTier(stack) == Tier.Two

src/main/scala/li/cil/oc/common/template/TabletTemplate.scala

@@ -1,6 +1,7 @@
 package li.cil.oc.common.template
 
 import cpw.mods.fml.common.event.FMLInterModComms
+import li.cil.oc.common.item.TabletWrapper
 import li.cil.oc.{Settings, api}
 import li.cil.oc.common.{Slot, Tier}
 import li.cil.oc.server.driver.item
@@ -17,11 +18,13 @@ object TabletTemplate extends Template {
     "GraphicsCard" -> ((inventory: IInventory) => Array("graphicsCard1", "graphicsCard2", "graphicsCard3").exists(name => hasComponent(name)(inventory))),
     "OS" -> hasFileSystem _)
 
+  override protected def hostClass = classOf[TabletWrapper]
+
   def select(stack: ItemStack) = api.Items.get(stack) == api.Items.get("tabletCase")
 
   def validate(inventory: IInventory): Array[AnyRef] = validateComputer(inventory)
 
-  def validateUpgrade(inventory: IInventory, slot: Int, tier: Int, stack: ItemStack): Boolean = Option(api.Driver.driverFor(stack)) match {
+  def validateUpgrade(inventory: IInventory, slot: Int, tier: Int, stack: ItemStack): Boolean = Option(api.Driver.driverFor(stack, hostClass)) match {
     case Some(driver) if driver.slot(stack) == Slot.Upgrade =>
       driver != item.Screen &&
         driver.slot(stack) == Slot.Upgrade && driver.tier(stack) <= tier

src/main/scala/li/cil/oc/common/template/Template.scala

@@ -1,6 +1,6 @@
 package li.cil.oc.common.template
 
-import li.cil.oc.api.driver.{Container, Inventory, Memory, Processor}
+import li.cil.oc.api.driver._
 import li.cil.oc.common.{Slot, Tier}
 import li.cil.oc.{Localization, Settings, api}
 import net.minecraft.inventory.IInventory
@@ -17,6 +17,8 @@ abstract class Template {
     "Inventory" -> hasInventory _,
     "OS" -> hasFileSystem _)
 
+  protected def hostClass: Class[_ <: EnvironmentHost]
+
   protected def validateComputer(inventory: IInventory): Array[AnyRef] = {
     val hasCase = caseTier(inventory) != Tier.None
     val hasCPU = this.hasCPU(inventory)
@@ -51,12 +53,12 @@ abstract class Template {
     })
   }
 
-  protected def hasCPU(inventory: IInventory) = exists(inventory, api.Driver.driverFor(_) match {
+  protected def hasCPU(inventory: IInventory) = exists(inventory, api.Driver.driverFor(_, hostClass) match {
     case _: Processor => true
     case _ => false
   })
 
-  protected def hasRAM(inventory: IInventory) = exists(inventory, api.Driver.driverFor(_) match {
+  protected def hasRAM(inventory: IInventory) = exists(inventory, api.Driver.driverFor(_, hostClass) match {
     case _: Memory => true
     case _ => false
   })
@@ -66,12 +68,12 @@ abstract class Template {
     case _ => false
   })
 
-  protected def hasInventory(inventory: IInventory) = exists(inventory, api.Driver.driverFor(_) match {
+  protected def hasInventory(inventory: IInventory) = exists(inventory, api.Driver.driverFor(_, hostClass) match {
     case _: Inventory => true
     case _ => false
   })
 
-  protected def hasFileSystem(inventory: IInventory) = exists(inventory, stack => Option(api.Driver.driverFor(stack)) match {
+  protected def hasFileSystem(inventory: IInventory) = exists(inventory, stack => Option(api.Driver.driverFor(stack, hostClass)) match {
     case Some(driver) => driver.slot(stack) == Slot.Floppy || driver.slot(stack) == Slot.HDD
     case _ => false
   })
@@ -80,7 +82,7 @@ abstract class Template {
     var acc = 0
     for (slot <- 1 until inventory.getSizeInventory) {
       val stack = inventory.getStackInSlot(slot)
-      acc += (Option(api.Driver.driverFor(stack)) match {
+      acc += (Option(api.Driver.driverFor(stack, hostClass)) match {
         case Some(driver: Processor) => 0 // CPUs are exempt, since they control the limit.
         case Some(driver: Container) => (1 + driver.tier(stack)) * 2
         case Some(driver) => 1 + driver.tier(stack)
@@ -94,7 +96,7 @@ abstract class Template {
     val caseTier = this.caseTier(inventory)
     val cpuTier = (0 until inventory.getSizeInventory).foldRight(0)((slot, acc) => {
       val stack = inventory.getStackInSlot(slot)
-      acc + (api.Driver.driverFor(stack) match {
+      acc + (api.Driver.driverFor(stack, hostClass) match {
         case processor: Processor => processor.tier(stack)
         case _ => 0
       })

src/main/scala/li/cil/oc/common/tileentity/Case.scala

@@ -33,7 +33,7 @@ class Case(var tier: Int) extends traits.PowerAcceptor with traits.Computer with
 
   def recomputeMaxComponents() {
     maxComponents = items.foldLeft(0)((sum, stack) => sum + (stack match {
-      case Some(item) => Option(Driver.driverFor(item, host)) match {
+      case Some(item) => Option(Driver.driverFor(item, getClass)) match {
         case Some(driver: driver.Processor) => driver.supportedComponents(item)
         case _ => 0
       }
@@ -42,7 +42,7 @@ class Case(var tier: Int) extends traits.PowerAcceptor with traits.Computer with
   }
 
   override def installedMemory = items.foldLeft(0)((sum, stack) => sum + (stack match {
-    case Some(item) => Option(Driver.driverFor(item, host)) match {
+    case Some(item) => Option(Driver.driverFor(item, getClass)) match {
       case Some(driver: driver.Memory) => driver.amount(item)
       case _ => 0
     }
@@ -114,7 +114,7 @@ class Case(var tier: Int) extends traits.PowerAcceptor with traits.Computer with
     super.isUseableByPlayer(player) && (!isCreativeCase || player.capabilities.isCreativeMode)
 
   override def isItemValidForSlot(slot: Int, stack: ItemStack) =
-    Option(Driver.driverFor(stack, host)).fold(false)(driver => {
+    Option(Driver.driverFor(stack, getClass)).fold(false)(driver => {
       val provided = InventorySlots.computer(tier)(slot)
       driver.slot(stack) == provided.slot && driver.tier(stack) <= provided.tier
     })

src/main/scala/li/cil/oc/common/tileentity/Charger.scala

@@ -140,7 +140,7 @@ class Charger extends traits.Environment with traits.PowerAcceptor with traits.R
 
   override def getSizeInventory = 1
 
-  override def isItemValidForSlot(slot: Int, stack: ItemStack) = (slot, Option(Driver.driverFor(stack, host))) match {
+  override def isItemValidForSlot(slot: Int, stack: ItemStack) = (slot, Option(Driver.driverFor(stack, getClass))) match {
     case (0, Some(driver)) => driver.slot(stack) == Slot.Tablet
     case _ => false
   }

src/main/scala/li/cil/oc/common/tileentity/DiskDrive.scala

@@ -29,7 +29,7 @@ class DiskDrive extends traits.Environment with traits.ComponentInventory with t
 
   override def getSizeInventory = 1
 
-  override def isItemValidForSlot(slot: Int, stack: ItemStack) = (slot, Option(Driver.driverFor(stack, host))) match {
+  override def isItemValidForSlot(slot: Int, stack: ItemStack) = (slot, Option(Driver.driverFor(stack, getClass))) match {
     case (0, Some(driver)) => driver.slot(stack) == Slot.Floppy
     case _ => false
   }

src/main/scala/li/cil/oc/common/tileentity/Keyboard.scala

@@ -13,7 +13,7 @@ class Keyboard extends traits.Environment with traits.Rotatable with traits.Immi
 
   val keyboard = {
     val keyboardItem = api.Items.get("keyboard").createItemStack(1)
-    api.Driver.driverFor(keyboardItem, this).createEnvironment(keyboardItem, this)
+    api.Driver.driverFor(keyboardItem, getClass).createEnvironment(keyboardItem, this)
   }
 
   override def node = keyboard.node

src/main/scala/li/cil/oc/common/tileentity/Robot.scala

@@ -72,7 +72,7 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
     components(slot) match {
       case Some(component) =>
         // We're guaranteed to have a driver for entries.
-        save(component, Driver.driverFor(stack, host), stack)
+        save(component, Driver.driverFor(stack, getClass), stack)
       case _ =>
     }
     ServerPacketSender.sendRobotInventory(this, slot, stack)
@@ -493,7 +493,7 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
 
   def containerSlotType(slot: Int) = if (containerSlots contains slot) {
     val stack = info.containers(slot - 1)
-    Option(Driver.driverFor(stack, host)) match {
+    Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver: api.driver.Container) => driver.providedSlot(stack)
       case _ => Slot.None
     }
@@ -502,7 +502,7 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
 
   def containerSlotTier(slot: Int) = if (containerSlots contains slot) {
     val stack = info.containers(slot - 1)
-    Option(Driver.driverFor(stack, host)) match {
+    Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver: api.driver.Container) => driver.providedTier(stack)
       case _ => Tier.None
     }
@@ -516,7 +516,7 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
   def isInventorySlot(slot: Int) = inventorySlots contains slot
 
   def isFloppySlot(slot: Int) = isComponentSlot(slot) && (Option(getStackInSlot(slot)) match {
-    case Some(stack) => Option(Driver.driverFor(stack, host)) match {
+    case Some(stack) => Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver) => driver.slot(stack) == Slot.Floppy
       case _ => false
     }
@@ -528,7 +528,7 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
   // ----------------------------------------------------------------------- //
 
   override def installedMemory = (containerSlots ++ componentSlots).foldLeft(0)((acc, slot) => acc + (Option(getStackInSlot(slot)) match {
-    case Some(stack) => Option(Driver.driverFor(stack, host)) match {
+    case Some(stack) => Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver: api.driver.Memory) => driver.amount(stack)
       case _ => 0
     }
@@ -537,10 +537,10 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
 
   override def componentSlot(address: String) = components.indexWhere(_.exists(env => env.node != null && env.node.address == address))
 
-  override def hasRedstoneCard = (containerSlots ++ componentSlots).exists(slot => Option(getStackInSlot(slot)).fold(false)(driver.item.RedstoneCard.worksWith(_, host)))
+  override def hasRedstoneCard = (containerSlots ++ componentSlots).exists(slot => Option(getStackInSlot(slot)).fold(false)(driver.item.RedstoneCard.worksWith(_, getClass)))
 
   private def computeInventorySize() = math.min(maxInventorySize, (containerSlots ++ componentSlots).foldLeft(0)((acc, slot) => acc + (Option(getStackInSlot(slot)) match {
-    case Some(stack) => Option(Driver.driverFor(stack, host)) match {
+    case Some(stack) => Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver: api.driver.Inventory) => driver.inventoryCapacity(stack)
       case _ => 0
     }
@@ -607,7 +607,7 @@ class Robot extends traits.Computer with traits.PowerInformation with tileentity
     }
   }
 
-  override def isItemValidForSlot(slot: Int, stack: ItemStack) = (slot, Option(Driver.driverFor(stack, host))) match {
+  override def isItemValidForSlot(slot: Int, stack: ItemStack) = (slot, Option(Driver.driverFor(stack, getClass))) match {
     case (0, _) => true // Allow anything in the tool slot.
     case (i, Some(driver)) if isContainerSlot(i) =>
       // Yay special cases! Dynamic screens kind of work, but are pretty derpy

src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala

@@ -93,7 +93,7 @@ class ServerRack extends traits.PowerAcceptor with traits.Hub with traits.PowerB
 
   def hasAbstractBusCard = servers exists {
     case Some(server) => server.machine.isRunning && server.inventory.items.exists {
-      case Some(stack) => driver.item.AbstractBusCard.worksWith(stack, server.inventory.host)
+      case Some(stack) => driver.item.AbstractBusCard.worksWith(stack, getClass)
       case _ => false
     }
     case _ => false
@@ -101,7 +101,7 @@ class ServerRack extends traits.PowerAcceptor with traits.Hub with traits.PowerB
 
   def hasRedstoneCard = servers exists {
     case Some(server) => server.machine.isRunning && server.inventory.items.exists {
-      case Some(stack) => driver.item.RedstoneCard.worksWith(stack, server.inventory.host)
+      case Some(stack) => driver.item.RedstoneCard.worksWith(stack, getClass)
       case _ => false
     }
     case _ => false

src/main/scala/li/cil/oc/common/tileentity/Switch.scala

@@ -134,7 +134,7 @@ class Switch extends traits.Hub with traits.NotAnalyzable with IPeripheral with
   }
 
   private def updateLimits(slot: Int, stack: ItemStack) {
-    Driver.driverFor(stack, host) match {
+    Driver.driverFor(stack, getClass) match {
       case driver if driver.slot(stack) == Slot.CPU =>
         relayDelay = math.max(1, relayBaseDelay - ((driver.tier(stack) + 1) * relayDelayPerUpgrade))
       case driver if driver.slot(stack) == Slot.Memory =>
@@ -149,7 +149,7 @@ class Switch extends traits.Hub with traits.NotAnalyzable with IPeripheral with
 
   override protected def onItemRemoved(slot: Int, stack: ItemStack) {
     super.onItemRemoved(slot, stack)
-    Driver.driverFor(stack, host) match {
+    Driver.driverFor(stack, getClass) match {
       case driver if driver.slot(stack) == Slot.CPU => relayDelay = relayBaseDelay
       case driver if driver.slot(stack) == Slot.Memory => relayAmount = relayBaseAmount
       case driver if driver.slot(stack) == Slot.HDD => maxQueueSize = queueBaseSize
@@ -159,7 +159,7 @@ class Switch extends traits.Hub with traits.NotAnalyzable with IPeripheral with
   override def getSizeInventory = InventorySlots.switch.length
 
   override def isItemValidForSlot(slot: Int, stack: ItemStack) =
-    Option(Driver.driverFor(stack, host)).fold(false)(driver => {
+    Option(Driver.driverFor(stack, getClass)).fold(false)(driver => {
       val provided = InventorySlots.switch(slot)
       driver.slot(stack) == provided.slot && driver.tier(stack) <= provided.tier
     })

src/main/scala/li/cil/oc/common/tileentity/traits/Computer.scala

@@ -64,7 +64,7 @@ trait Computer extends Environment with ComponentInventory with Rotatable with B
 
   override def cpuArchitecture: Class[_ <: Architecture] = {
     for (i <- 0 until getSizeInventory if isComponentSlot(i)) Option(getStackInSlot(i)) match {
-      case Some(s) => Option(Driver.driverFor(s, host)) match {
+      case Some(s) => Option(Driver.driverFor(s, getClass)) match {
         case Some(driver: Processor) if driver.slot(s) == Slot.CPU => return driver.architecture(s)
         case _ =>
       }
@@ -84,12 +84,12 @@ trait Computer extends Environment with ComponentInventory with Rotatable with B
   override def onMachineDisconnect(node: Node) = this.onDisconnect(node)
 
   def hasAbstractBusCard = items.exists {
-    case Some(item) => machine.isRunning && driver.item.AbstractBusCard.worksWith(item, host)
+    case Some(item) => machine.isRunning && driver.item.AbstractBusCard.worksWith(item, getClass)
     case _ => false
   }
 
   def hasRedstoneCard = items.exists {
-    case Some(item) => machine.isRunning && driver.item.RedstoneCard.worksWith(item, host)
+    case Some(item) => machine.isRunning && driver.item.RedstoneCard.worksWith(item, getClass)
     case _ => false
   }
 

src/main/scala/li/cil/oc/common/tileentity/traits/TextBuffer.scala

@@ -7,7 +7,7 @@ import net.minecraft.nbt.NBTTagCompound
 trait TextBuffer extends Environment {
   lazy val buffer = {
     val screenItem = api.Items.get("screen1").createItemStack(1)
-    val buffer = api.Driver.driverFor(screenItem, this).createEnvironment(screenItem, this).asInstanceOf[api.component.TextBuffer]
+    val buffer = api.Driver.driverFor(screenItem, getClass).createEnvironment(screenItem, this).asInstanceOf[api.component.TextBuffer]
     val (maxWidth, maxHeight) = Settings.screenResolutionsByTier(tier)
     buffer.setMaximumResolution(maxWidth, maxHeight)
     buffer.setMaximumColorDepth(Settings.screenDepthsByTier(tier))

src/main/scala/li/cil/oc/server/component/Server.scala

@@ -25,7 +25,7 @@ class Server(val rack: tileentity.ServerRack, val number: Int) extends MachineHo
 
   override def cpuArchitecture: Class[_ <: Architecture] = {
     for (i <- 0 until inventory.getSizeInventory if inventory.isComponentSlot(i)) Option(inventory.getStackInSlot(i)) match {
-      case Some(s) => Option(Driver.driverFor(s, inventory.host)) match {
+      case Some(s) => Option(Driver.driverFor(s, rack.getClass)) match {
         case Some(driver: Processor) if driver.slot(s) == Slot.CPU => return driver.architecture(s)
         case _ =>
       }
@@ -35,7 +35,7 @@ class Server(val rack: tileentity.ServerRack, val number: Int) extends MachineHo
   }
 
   override def installedMemory = inventory.items.foldLeft(0)((sum, stack) => sum + (stack match {
-    case Some(item) => Option(Driver.driverFor(item, inventory.host)) match {
+    case Some(item) => Option(Driver.driverFor(item, rack.getClass)) match {
       case Some(driver: driver.Memory) => driver.amount(item)
       case _ => 0
     }
@@ -44,7 +44,7 @@ class Server(val rack: tileentity.ServerRack, val number: Int) extends MachineHo
 
   lazy val maxComponents = if (!hasCPU) 0
   else inventory.items.foldLeft(0)((sum, stack) => sum + (stack match {
-    case Some(item) => Option(Driver.driverFor(item, inventory.host)) match {
+    case Some(item) => Option(Driver.driverFor(item, rack.getClass)) match {
       case Some(driver: driver.Processor) => driver.supportedComponents(item)
       case _ => 0
     }
@@ -54,7 +54,7 @@ class Server(val rack: tileentity.ServerRack, val number: Int) extends MachineHo
   override def componentSlot(address: String) = inventory.components.indexWhere(_.exists(env => env.node != null && env.node.address == address))
 
   def hasCPU = inventory.items.exists {
-    case Some(stack) => Option(Driver.driverFor(stack, inventory.host)) match {
+    case Some(stack) => Option(Driver.driverFor(stack, rack.getClass)) match {
       case Some(driver) => driver.slot(stack) == Slot.CPU
       case _ => false
     }

src/main/scala/li/cil/oc/server/driver/Registry.scala

@@ -57,7 +57,7 @@ private[oc] object Registry extends api.detail.DriverAPI {
       case _ => null
     }
 
-  def driverFor(stack: ItemStack, host: EnvironmentHost) =
+  def driverFor(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     if (stack != null) items.find(_.worksWith(stack, host)).orNull
     else null
 

src/main/scala/li/cil/oc/server/driver/item/AbstractBusCard.scala

@@ -12,7 +12,7 @@ object AbstractBusCard extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("abstractBusCard"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
      super.worksWith(stack, host) && isComputer(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = if (Mods.StargateTech2.isAvailable) host match {

src/main/scala/li/cil/oc/server/driver/item/Item.scala

@@ -12,15 +12,17 @@ trait Item extends driver.Item {
 
   override def dataTag(stack: ItemStack) = Item.dataTag(stack)
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) = worksWith(stack)
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) = worksWith(stack)
 
   protected def isOneOf(stack: ItemStack, items: api.detail.ItemInfo*) = items.filter(_ != null).contains(api.Items.get(stack))
 
-  protected def isComputer(host: EnvironmentHost) = host.isInstanceOf[tileentity.traits.Computer] || host.isInstanceOf[tileentity.ServerRack]
+  protected def isRotatable(host: Class[_ <: EnvironmentHost]) = classOf[api.tileentity.Rotatable].isAssignableFrom(host)
 
-  protected def isRobot(host: EnvironmentHost) = host.isInstanceOf[api.tileentity.Robot]
+  protected def isComputer(host: Class[_ <: EnvironmentHost]) = host.isInstanceOf[tileentity.traits.Computer] || host.isInstanceOf[tileentity.ServerRack]
 
-  protected def isTablet(host: EnvironmentHost) = host.isInstanceOf[item.TabletWrapper]
+  protected def isRobot(host: Class[_ <: EnvironmentHost]) = host.isInstanceOf[api.tileentity.Robot]
+
+  protected def isTablet(host: Class[_ <: EnvironmentHost]) = host.isInstanceOf[item.TabletWrapper]
 }
 
 object Item {

src/main/scala/li/cil/oc/server/driver/item/NetworkCard.scala

@@ -10,7 +10,7 @@ object NetworkCard extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("lanCard"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && !isTablet(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = new component.NetworkCard()

src/main/scala/li/cil/oc/server/driver/item/RedstoneCard.scala

@@ -11,7 +11,7 @@ import net.minecraft.item.ItemStack
 object RedstoneCard extends Item {
   override def worksWith(stack: ItemStack) = isOneOf(stack, api.Items.get("redstoneCard1"), api.Items.get("redstoneCard2"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isComputer(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) =

src/main/scala/li/cil/oc/server/driver/item/Screen.scala

@@ -9,7 +9,7 @@ object Screen extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("screen1"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && !isTablet(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = host match {

src/main/scala/li/cil/oc/server/driver/item/Tablet.scala

@@ -12,13 +12,13 @@ object Tablet extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("tablet"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isTablet(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = {
     val data = new ItemUtils.TabletData(stack)
     data.items.collect {
-      case Some(fs) if FileSystem.worksWith(fs, host) => fs
+      case Some(fs) if FileSystem.worksWith(fs, host.getClass) => fs
     }.headOption.map(FileSystem.createEnvironment(_, host)).orNull
   }
 

src/main/scala/li/cil/oc/server/driver/item/UpgradeAngel.scala

@@ -10,7 +10,7 @@ object UpgradeAngel extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("angelUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = new component.UpgradeAngel()

src/main/scala/li/cil/oc/server/driver/item/UpgradeChunkloader.scala

@@ -10,7 +10,7 @@ object UpgradeChunkloader extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("chunkloaderUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = new component.UpgradeChunkloader(host)

src/main/scala/li/cil/oc/server/driver/item/UpgradeCrafting.scala

@@ -11,7 +11,7 @@ object UpgradeCrafting extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("craftingUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) =

src/main/scala/li/cil/oc/server/driver/item/UpgradeExperience.scala

@@ -10,7 +10,7 @@ object UpgradeExperience extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("experienceUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = new component.UpgradeExperience()

src/main/scala/li/cil/oc/server/driver/item/UpgradeGenerator.scala

@@ -11,7 +11,7 @@ object UpgradeGenerator extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("generatorUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) =

src/main/scala/li/cil/oc/server/driver/item/UpgradeInventory.scala

@@ -9,7 +9,7 @@ object UpgradeInventory extends Item with Inventory {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("inventoryUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = null

src/main/scala/li/cil/oc/server/driver/item/UpgradeInventoryController.scala

@@ -11,7 +11,7 @@ object UpgradeInventoryController extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("inventoryControllerUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && isRobot(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = host match {

src/main/scala/li/cil/oc/server/driver/item/UpgradeNavigation.scala

@@ -11,8 +11,8 @@ object UpgradeNavigation extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("navigationUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
-    super.worksWith(stack, host) && host.isInstanceOf[Rotatable]
+    super.worksWith(stack, host) && isRotatable(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) =
     host match {

src/main/scala/li/cil/oc/server/driver/item/UpgradePiston.scala

@@ -11,8 +11,8 @@ object UpgradePiston extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("pistonUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
-    super.worksWith(stack, host) && host.isInstanceOf[Rotatable]
+    super.worksWith(stack, host) && isRotatable(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = host match {
     case rotatable: Rotatable with EnvironmentHost => new component.UpgradePiston(rotatable)

src/main/scala/li/cil/oc/server/driver/item/UpgradeSign.scala

@@ -11,8 +11,8 @@ object UpgradeSign extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("signUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
-    super.worksWith(stack, host) && host.isInstanceOf[Rotatable]
+    super.worksWith(stack, host) && isRotatable(host)
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) =
     host match {

src/main/scala/li/cil/oc/server/driver/item/UpgradeTractorBeam.scala

@@ -12,7 +12,7 @@ object UpgradeTractorBeam extends Item {
   override def worksWith(stack: ItemStack) =
     isOneOf(stack, api.Items.get("tractorBeamUpgrade"))
 
-  override def worksWith(stack: ItemStack, host: EnvironmentHost) =
+  override def worksWith(stack: ItemStack, host: Class[_ <: EnvironmentHost]) =
     super.worksWith(stack, host) && (isRobot(host) || isTablet(host))
 
   override def createEnvironment(stack: ItemStack, host: EnvironmentHost) = host match {