diff --git a/README.md b/README.md
index ee3c63844..ab2cb561f 100644
--- a/README.md
+++ b/README.md
@@ -57,7 +57,7 @@ dependencies {
 }
 
 dependencies {
-  implementation "org.squiddev:cc-tweaked:${mc_version}-${cct_version}"
+  implementation "org.squiddev:cc-tweaked-${mc_version}:${cct_version}"
 }
 ```
 
diff --git a/build.gradle b/build.gradle
index 9e76bee8f..8f751ab63 100644
--- a/build.gradle
+++ b/build.gradle
@@ -17,6 +17,7 @@ buildscript {
 
 plugins {
     id 'com.matthewprenger.cursegradle' version '1.2.0'
+    id "com.github.breadmoirai.github-release" version "2.2.4"
 }
 
 apply plugin: 'net.minecraftforge.gradle'
@@ -330,6 +331,20 @@ uploadArchives {
     }
 }
 
+githubRelease {
+    token project.hasProperty('githubApiKey') ? project.githubApiKey : ''
+    owner 'SquidDev-CC'
+    repo 'CC-Tweaked'
+    targetCommitish (mc_version == "1.12.2" ? "master" : mc_version)
+
+    tagName "v${mc_version}-${mod_version}"
+    releaseName "[${mc_version}] ${mod_version}"
+    body ''
+    prerelease true
+
+    releaseAssets.from(jar.archivePath)
+}
+
 test {
     useJUnitPlatform()
     testLogging {
diff --git a/gradle.properties b/gradle.properties
index 2c0e51d49..90ef03b55 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,5 @@
 # Mod properties
-mod_version=1.82.0
+mod_version=1.82.1
 
 # Minecraft properties
 mc_version=1.13.2
diff --git a/src/main/java/dan200/computercraft/core/apis/ApiFactories.java b/src/main/java/dan200/computercraft/core/apis/ApiFactories.java
index d4b0adc66..e37b7b594 100644
--- a/src/main/java/dan200/computercraft/core/apis/ApiFactories.java
+++ b/src/main/java/dan200/computercraft/core/apis/ApiFactories.java
@@ -6,13 +6,13 @@
 
 package dan200.computercraft.core.apis;
 
-import com.google.common.base.Preconditions;
 import dan200.computercraft.api.lua.ILuaAPIFactory;
 
 import javax.annotation.Nonnull;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashSet;
+import java.util.Objects;
 
 public final class ApiFactories
 {
@@ -25,7 +25,7 @@ public final class ApiFactories
 
     public static synchronized void register( @Nonnull ILuaAPIFactory factory )
     {
-        Preconditions.checkNotNull( factory, "provider cannot be null" );
+        Objects.requireNonNull( factory, "provider cannot be null" );
         factories.add( factory );
     }
 
diff --git a/src/main/java/dan200/computercraft/core/apis/ComputerAccess.java b/src/main/java/dan200/computercraft/core/apis/ComputerAccess.java
index 693a4ede4..52341b92b 100644
--- a/src/main/java/dan200/computercraft/core/apis/ComputerAccess.java
+++ b/src/main/java/dan200/computercraft/core/apis/ComputerAccess.java
@@ -6,7 +6,6 @@
 
 package dan200.computercraft.core.apis;
 
-import com.google.common.base.Preconditions;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.peripheral.IComputerAccess;
@@ -121,7 +120,7 @@ public abstract class ComputerAccess implements IComputerAccess
     @Override
     public void queueEvent( @Nonnull final String event, final Object[] arguments )
     {
-        Preconditions.checkNotNull( event, "event cannot be null" );
+        Objects.requireNonNull( event, "event cannot be null" );
         m_environment.queueEvent( event, arguments );
     }
 
diff --git a/src/main/java/dan200/computercraft/core/apis/IAPIEnvironment.java b/src/main/java/dan200/computercraft/core/apis/IAPIEnvironment.java
index 4cb3670a9..92ef98d32 100644
--- a/src/main/java/dan200/computercraft/core/apis/IAPIEnvironment.java
+++ b/src/main/java/dan200/computercraft/core/apis/IAPIEnvironment.java
@@ -8,6 +8,7 @@ package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.computer.IComputerEnvironment;
 import dan200.computercraft.core.filesystem.FileSystem;
 import dan200.computercraft.core.terminal.Terminal;
@@ -18,16 +19,10 @@ import javax.annotation.Nullable;
 
 public interface IAPIEnvironment
 {
-    String[] SIDE_NAMES = new String[] {
-        "bottom", "top", "back", "front", "right", "left",
-    };
-
-    int SIDE_COUNT = 6;
-
     @FunctionalInterface
     interface IPeripheralChangeListener
     {
-        void onPeripheralChanged( int side, @Nullable IPeripheral newPeripheral );
+        void onPeripheralChanged( ComputerSide side, @Nullable IPeripheral newPeripheral );
     }
 
     int getComputerID();
@@ -49,22 +44,22 @@ public interface IAPIEnvironment
 
     void queueEvent( String event, Object[] args );
 
-    void setOutput( int side, int output );
+    void setOutput( ComputerSide side, int output );
 
-    int getOutput( int side );
+    int getOutput( ComputerSide side );
 
-    int getInput( int side );
+    int getInput( ComputerSide side );
 
-    void setBundledOutput( int side, int output );
+    void setBundledOutput( ComputerSide side, int output );
 
-    int getBundledOutput( int side );
+    int getBundledOutput( ComputerSide side );
 
-    int getBundledInput( int side );
+    int getBundledInput( ComputerSide side );
 
     void setPeripheralChangeListener( @Nullable IPeripheralChangeListener listener );
 
     @Nullable
-    IPeripheral getPeripheral( int side );
+    IPeripheral getPeripheral( ComputerSide side );
 
     String getLabel();
 
diff --git a/src/main/java/dan200/computercraft/core/apis/PeripheralAPI.java b/src/main/java/dan200/computercraft/core/apis/PeripheralAPI.java
index 6066cc7b0..eb77fe12b 100644
--- a/src/main/java/dan200/computercraft/core/apis/PeripheralAPI.java
+++ b/src/main/java/dan200/computercraft/core/apis/PeripheralAPI.java
@@ -12,6 +12,7 @@ import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.tracking.TrackingField;
 
 import javax.annotation.Nonnull;
@@ -245,32 +246,33 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
     // IPeripheralChangeListener
 
     @Override
-    public void onPeripheralChanged( int side, IPeripheral newPeripheral )
+    public void onPeripheralChanged( ComputerSide side, IPeripheral newPeripheral )
     {
         synchronized( m_peripherals )
         {
-            if( m_peripherals[side] != null )
+            int index = side.ordinal();
+            if( m_peripherals[index] != null )
             {
                 // Queue a detachment
-                final PeripheralWrapper wrapper = m_peripherals[side];
+                final PeripheralWrapper wrapper = m_peripherals[index];
                 if( wrapper.isAttached() ) wrapper.detach();
 
                 // Queue a detachment event
-                m_environment.queueEvent( "peripheral_detach", new Object[] { IAPIEnvironment.SIDE_NAMES[side] } );
+                m_environment.queueEvent( "peripheral_detach", new Object[] { side.getName() } );
             }
 
             // Assign the new peripheral
-            m_peripherals[side] = newPeripheral == null ? null
-                : new PeripheralWrapper( newPeripheral, IAPIEnvironment.SIDE_NAMES[side] );
+            m_peripherals[index] = newPeripheral == null ? null
+                : new PeripheralWrapper( newPeripheral, side.getName() );
 
-            if( m_peripherals[side] != null )
+            if( m_peripherals[index] != null )
             {
                 // Queue an attachment
-                final PeripheralWrapper wrapper = m_peripherals[side];
+                final PeripheralWrapper wrapper = m_peripherals[index];
                 if( m_running && !wrapper.isAttached() ) wrapper.attach();
 
                 // Queue an attachment event
-                m_environment.queueEvent( "peripheral", new Object[] { IAPIEnvironment.SIDE_NAMES[side] } );
+                m_environment.queueEvent( "peripheral", new Object[] { side.getName() } );
             }
         }
     }
@@ -337,16 +339,13 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             {
                 // isPresent
                 boolean present = false;
-                int side = parseSide( args );
-                if( side >= 0 )
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+                if( side != null )
                 {
                     synchronized( m_peripherals )
                     {
-                        PeripheralWrapper p = m_peripherals[side];
-                        if( p != null )
-                        {
-                            present = true;
-                        }
+                        PeripheralWrapper p = m_peripherals[side.ordinal()];
+                        if( p != null ) present = true;
                     }
                 }
                 return new Object[] { present };
@@ -354,21 +353,14 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             case 1:
             {
                 // getType
-                String type = null;
-                int side = parseSide( args );
-                if( side >= 0 )
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+                if( side != null )
                 {
+                    String type = null;
                     synchronized( m_peripherals )
                     {
-                        PeripheralWrapper p = m_peripherals[side];
-                        if( p != null )
-                        {
-                            type = p.getType();
-                        }
-                    }
-                    if( type != null )
-                    {
-                        return new Object[] { type };
+                        PeripheralWrapper p = m_peripherals[side.ordinal()];
+                        if( p != null ) return new Object[] { p.getType() };
                     }
                 }
                 return null;
@@ -377,12 +369,12 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             {
                 // getMethods
                 String[] methods = null;
-                int side = parseSide( args );
-                if( side >= 0 )
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+                if( side != null )
                 {
                     synchronized( m_peripherals )
                     {
-                        PeripheralWrapper p = m_peripherals[side];
+                        PeripheralWrapper p = m_peripherals[side.ordinal()];
                         if( p != null )
                         {
                             methods = p.getMethods();
@@ -403,16 +395,16 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             case 3:
             {
                 // call
-                int side = parseSide( args );
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
                 String methodName = getString( args, 1 );
                 Object[] methodArgs = Arrays.copyOfRange( args, 2, args.length );
 
-                if( side >= 0 )
+                if( side != null )
                 {
                     PeripheralWrapper p;
                     synchronized( m_peripherals )
                     {
-                        p = m_peripherals[side];
+                        p = m_peripherals[side.ordinal()];
                     }
                     if( p != null )
                     {
@@ -425,19 +417,4 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
                 return null;
         }
     }
-
-    // Privates
-
-    private int parseSide( Object[] args ) throws LuaException
-    {
-        String side = getString( args, 0 );
-        for( int n = 0; n < IAPIEnvironment.SIDE_NAMES.length; n++ )
-        {
-            if( side.equals( IAPIEnvironment.SIDE_NAMES[n] ) )
-            {
-                return n;
-            }
-        }
-        return -1;
-    }
 }
diff --git a/src/main/java/dan200/computercraft/core/apis/RedstoneAPI.java b/src/main/java/dan200/computercraft/core/apis/RedstoneAPI.java
index 2ce68a58c..d36ba9186 100644
--- a/src/main/java/dan200/computercraft/core/apis/RedstoneAPI.java
+++ b/src/main/java/dan200/computercraft/core/apis/RedstoneAPI.java
@@ -9,6 +9,7 @@ package dan200.computercraft.core.apis;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.core.computer.ComputerSide;
 
 import javax.annotation.Nonnull;
 import java.util.HashMap;
@@ -64,56 +65,40 @@ public class RedstoneAPI implements ILuaAPI
             {
                 // getSides
                 Map<Object, Object> table = new HashMap<>();
-                for( int i = 0; i < IAPIEnvironment.SIDE_NAMES.length; i++ )
+                for( int i = 0; i < ComputerSide.NAMES.length; i++ )
                 {
-                    table.put( i + 1, IAPIEnvironment.SIDE_NAMES[i] );
+                    table.put( i + 1, ComputerSide.NAMES[i] );
                 }
                 return new Object[] { table };
             }
             case 1:
             {
                 // setOutput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 boolean output = getBoolean( args, 1 );
                 m_environment.setOutput( side, output ? 15 : 0 );
                 return null;
             }
-            case 2:
-            {
-                // getOutput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getOutput( side ) > 0 };
-            }
-            case 3:
-            {
-                // getInput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getInput( side ) > 0 };
-            }
+            case 2: // getOutput
+                return new Object[] { m_environment.getOutput( parseSide( args ) ) > 0 };
+            case 3: // getInput
+                return new Object[] { m_environment.getInput( parseSide( args ) ) > 0 };
             case 4:
             {
                 // setBundledOutput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 int output = getInt( args, 1 );
                 m_environment.setBundledOutput( side, output );
                 return null;
             }
-            case 5:
-            {
-                // getBundledOutput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getBundledOutput( side ) };
-            }
-            case 6:
-            {
-                // getBundledInput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getBundledInput( side ) };
-            }
+            case 5: // getBundledOutput
+                return new Object[] { m_environment.getBundledOutput( parseSide( args ) ) };
+            case 6: // getBundledInput
+                return new Object[] { m_environment.getBundledInput( parseSide( args ) ) };
             case 7:
             {
                 // testBundledInput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 int mask = getInt( args, 1 );
                 int input = m_environment.getBundledInput( side );
                 return new Object[] { (input & mask) == mask };
@@ -122,7 +107,7 @@ public class RedstoneAPI implements ILuaAPI
             case 9:
             {
                 // setAnalogOutput/setAnalogueOutput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 int output = getInt( args, 1 );
                 if( output < 0 || output > 15 )
                 {
@@ -132,34 +117,20 @@ public class RedstoneAPI implements ILuaAPI
                 return null;
             }
             case 10:
-            case 11:
-            {
-                // getAnalogOutput/getAnalogueOutput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getOutput( side ) };
-            }
+            case 11: // getAnalogOutput/getAnalogueOutput
+                return new Object[] { m_environment.getOutput( parseSide( args ) ) };
             case 12:
-            case 13:
-            {
-                // getAnalogInput/getAnalogueInput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getInput( side ) };
-            }
+            case 13: // getAnalogInput/getAnalogueInput
+                return new Object[] { m_environment.getInput( parseSide( args ) ) };
             default:
                 return null;
         }
     }
 
-    private static int parseSide( Object[] args ) throws LuaException
+    private static ComputerSide parseSide( Object[] args ) throws LuaException
     {
-        String side = getString( args, 0 );
-        for( int n = 0; n < IAPIEnvironment.SIDE_NAMES.length; n++ )
-        {
-            if( side.equals( IAPIEnvironment.SIDE_NAMES[n] ) )
-            {
-                return n;
-            }
-        }
-        throw new LuaException( "Invalid side." );
+        ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+        if( side == null ) throw new LuaException( "Invalid side." );
+        return side;
     }
 }
diff --git a/src/main/java/dan200/computercraft/core/computer/Computer.java b/src/main/java/dan200/computercraft/core/computer/Computer.java
index 5c54e325d..5d95c7d2f 100644
--- a/src/main/java/dan200/computercraft/core/computer/Computer.java
+++ b/src/main/java/dan200/computercraft/core/computer/Computer.java
@@ -7,6 +7,7 @@
 package dan200.computercraft.core.computer;
 
 import com.google.common.base.Objects;
+import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
 import dan200.computercraft.core.apis.IAPIEnvironment;
diff --git a/src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java b/src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java
index 9fe3d5f48..78350d411 100644
--- a/src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java
+++ b/src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java
@@ -338,7 +338,7 @@ final class ComputerExecutor
         }
     }
 
-    private FileSystem createFileSystem()
+    IWritableMount getRootMount()
     {
         if( rootMount == null )
         {
@@ -347,11 +347,15 @@ final class ComputerExecutor
                 computer.getComputerEnvironment().getComputerSpaceLimit()
             );
         }
+        return rootMount;
+    }
 
+    private FileSystem createFileSystem()
+    {
         FileSystem filesystem = null;
         try
         {
-            filesystem = new FileSystem( "hdd", rootMount );
+            filesystem = new FileSystem( "hdd", getRootMount() );
 
             IMount romMount = getRomMount();
             if( romMount == null )
diff --git a/src/main/java/dan200/computercraft/core/computer/ComputerSide.java b/src/main/java/dan200/computercraft/core/computer/ComputerSide.java
new file mode 100644
index 000000000..d2937fd3b
--- /dev/null
+++ b/src/main/java/dan200/computercraft/core/computer/ComputerSide.java
@@ -0,0 +1,56 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.core.computer;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * A side on a computer. Unlike {@link net.minecraft.util.EnumFacing}, this is relative to the direction the computer is
+ * facing..
+ */
+public enum ComputerSide
+{
+    BOTTOM( "bottom" ),
+    TOP( "top" ),
+    BACK( "back" ),
+    FRONT( "front" ),
+    RIGHT( "right" ),
+    LEFT( "left" );
+
+    public static final String[] NAMES = new String[] { "bottom", "top", "back", "front", "right", "left" };
+
+    public static final int COUNT = 6;
+
+    private static final ComputerSide[] VALUES = values();
+
+    private final String name;
+
+    ComputerSide( String name ) {this.name = name;}
+
+    @Nonnull
+    public static ComputerSide valueOf( int side )
+    {
+        return VALUES[side];
+    }
+
+    @Nullable
+    public static ComputerSide valueOfInsensitive( @Nonnull String name )
+    {
+        for( ComputerSide side : VALUES )
+        {
+            if( side.name.equalsIgnoreCase( name ) ) return side;
+        }
+
+        return null;
+    }
+
+    public String getName()
+    {
+        return name;
+    }
+}
diff --git a/src/main/java/dan200/computercraft/core/computer/ComputerSystem.java b/src/main/java/dan200/computercraft/core/computer/ComputerSystem.java
index e6c39ec83..94eead340 100644
--- a/src/main/java/dan200/computercraft/core/computer/ComputerSystem.java
+++ b/src/main/java/dan200/computercraft/core/computer/ComputerSystem.java
@@ -26,12 +26,12 @@ import javax.annotation.Nullable;
  */
 public class ComputerSystem extends ComputerAccess implements IComputerSystem
 {
-    private final IAPIEnvironment m_environment;
+    private final IAPIEnvironment environment;
 
     ComputerSystem( IAPIEnvironment environment )
     {
         super( environment );
-        this.m_environment = environment;
+        this.environment = environment;
     }
 
     @Nonnull
@@ -45,7 +45,7 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
     @Override
     public IFileSystem getFileSystem()
     {
-        FileSystem fs = m_environment.getFileSystem();
+        FileSystem fs = environment.getFileSystem();
         return fs == null ? null : fs.getMountWrapper();
     }
 
@@ -53,6 +53,6 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
     @Override
     public String getLabel()
     {
-        return m_environment.getLabel();
+        return environment.getLabel();
     }
 }
diff --git a/src/main/java/dan200/computercraft/core/computer/Environment.java b/src/main/java/dan200/computercraft/core/computer/Environment.java
index e1612dd6d..b23ad377e 100644
--- a/src/main/java/dan200/computercraft/core/computer/Environment.java
+++ b/src/main/java/dan200/computercraft/core/computer/Environment.java
@@ -41,17 +41,17 @@ public final class Environment implements IAPIEnvironment
     private final Computer computer;
 
     private boolean internalOutputChanged = false;
-    private final int[] internalOutput = new int[SIDE_COUNT];
-    private final int[] internalBundledOutput = new int[SIDE_COUNT];
+    private final int[] internalOutput = new int[ComputerSide.COUNT];
+    private final int[] internalBundledOutput = new int[ComputerSide.COUNT];
 
-    private final int[] externalOutput = new int[SIDE_COUNT];
-    private final int[] externalBundledOutput = new int[SIDE_COUNT];
+    private final int[] externalOutput = new int[ComputerSide.COUNT];
+    private final int[] externalBundledOutput = new int[ComputerSide.COUNT];
 
     private boolean inputChanged = false;
-    private final int[] input = new int[SIDE_COUNT];
-    private final int[] bundledInput = new int[SIDE_COUNT];
+    private final int[] input = new int[ComputerSide.COUNT];
+    private final int[] bundledInput = new int[ComputerSide.COUNT];
 
-    private final IPeripheral[] peripherals = new IPeripheral[SIDE_COUNT];
+    private final IPeripheral[] peripherals = new IPeripheral[ComputerSide.COUNT];
     private IPeripheralChangeListener peripheralListener = null;
 
     Environment( Computer computer )
@@ -111,85 +111,89 @@ public final class Environment implements IAPIEnvironment
     }
 
     @Override
-    public int getInput( int side )
+    public int getInput( ComputerSide side )
     {
-        return input[side];
+        return input[side.ordinal()];
     }
 
     @Override
-    public int getBundledInput( int side )
+    public int getBundledInput( ComputerSide side )
     {
-        return bundledInput[side];
+        return bundledInput[side.ordinal()];
     }
 
     @Override
-    public void setOutput( int side, int output )
+    public void setOutput( ComputerSide side, int output )
     {
+        int index = side.ordinal();
         synchronized( internalOutput )
         {
-            if( internalOutput[side] != output )
+            if( internalOutput[index] != output )
             {
-                internalOutput[side] = output;
+                internalOutput[index] = output;
                 internalOutputChanged = true;
             }
         }
     }
 
     @Override
-    public int getOutput( int side )
+    public int getOutput( ComputerSide side )
     {
         synchronized( internalOutput )
         {
-            return computer.isOn() ? internalOutput[side] : 0;
+            return computer.isOn() ? internalOutput[side.ordinal()] : 0;
         }
     }
 
     @Override
-    public void setBundledOutput( int side, int output )
+    public void setBundledOutput( ComputerSide side, int output )
     {
+        int index = side.ordinal();
         synchronized( internalOutput )
         {
-            if( internalBundledOutput[side] != output )
+            if( internalBundledOutput[index] != output )
             {
-                internalBundledOutput[side] = output;
+                internalBundledOutput[index] = output;
                 internalOutputChanged = true;
             }
         }
     }
 
     @Override
-    public int getBundledOutput( int side )
+    public int getBundledOutput( ComputerSide side )
     {
         synchronized( internalOutput )
         {
-            return computer.isOn() ? internalBundledOutput[side] : 0;
+            return computer.isOn() ? internalBundledOutput[side.ordinal()] : 0;
         }
     }
 
-    public int getExternalRedstoneOutput( int side )
+    public int getExternalRedstoneOutput( ComputerSide side )
     {
-        return computer.isOn() ? externalOutput[side] : 0;
+        return computer.isOn() ? externalOutput[side.ordinal()] : 0;
     }
 
-    public int getExternalBundledRedstoneOutput( int side )
+    public int getExternalBundledRedstoneOutput( ComputerSide side )
     {
-        return computer.isOn() ? externalBundledOutput[side] : 0;
+        return computer.isOn() ? externalBundledOutput[side.ordinal()] : 0;
     }
 
-    public void setRedstoneInput( int side, int level )
+    public void setRedstoneInput( ComputerSide side, int level )
     {
-        if( input[side] != level )
+        int index = side.ordinal();
+        if( input[index] != level )
         {
-            input[side] = level;
+            input[index] = level;
             inputChanged = true;
         }
     }
 
-    public void setBundledRedstoneInput( int side, int combination )
+    public void setBundledRedstoneInput( ComputerSide side, int combination )
     {
-        if( bundledInput[side] != combination )
+        int index = side.ordinal();
+        if( bundledInput[index] != combination )
         {
-            bundledInput[side] = combination;
+            bundledInput[index] = combination;
             inputChanged = true;
         }
     }
@@ -222,7 +226,7 @@ public final class Environment implements IAPIEnvironment
 
             boolean changed = false;
 
-            for( int i = 0; i < SIDE_COUNT; i++ )
+            for( int i = 0; i < ComputerSide.COUNT; i++ )
             {
                 if( externalOutput[i] != internalOutput[i] )
                 {
@@ -255,24 +259,25 @@ public final class Environment implements IAPIEnvironment
     }
 
     @Override
-    public IPeripheral getPeripheral( int side )
+    public IPeripheral getPeripheral( ComputerSide side )
     {
         synchronized( peripherals )
         {
-            return peripherals[side];
+            return peripherals[side.ordinal()];
         }
     }
 
-    public void setPeripheral( int side, IPeripheral peripheral )
+    public void setPeripheral( ComputerSide side, IPeripheral peripheral )
     {
         synchronized( peripherals )
         {
-            IPeripheral existing = peripherals[side];
+            int index = side.ordinal();
+            IPeripheral existing = peripherals[index];
             if( (existing == null && peripheral != null) ||
                 (existing != null && peripheral == null) ||
                 (existing != null && !existing.equals( peripheral )) )
             {
-                peripherals[side] = peripheral;
+                peripherals[index] = peripheral;
                 if( peripheralListener != null ) peripheralListener.onPeripheralChanged( side, peripheral );
             }
         }
diff --git a/src/main/java/dan200/computercraft/shared/BundledRedstone.java b/src/main/java/dan200/computercraft/shared/BundledRedstone.java
index 78ee64eac..8c562c7a8 100644
--- a/src/main/java/dan200/computercraft/shared/BundledRedstone.java
+++ b/src/main/java/dan200/computercraft/shared/BundledRedstone.java
@@ -6,7 +6,6 @@
 
 package dan200.computercraft.shared;
 
-import com.google.common.base.Preconditions;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import dan200.computercraft.shared.common.DefaultBundledRedstoneProvider;
@@ -16,6 +15,7 @@ import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
 import java.util.LinkedHashSet;
+import java.util.Objects;
 import java.util.Set;
 
 public final class BundledRedstone
@@ -26,7 +26,7 @@ public final class BundledRedstone
 
     public static synchronized void register( @Nonnull IBundledRedstoneProvider provider )
     {
-        Preconditions.checkNotNull( provider, "provider cannot be null" );
+        Objects.requireNonNull( provider, "provider cannot be null" );
         providers.add( provider );
     }
 
diff --git a/src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java b/src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java
index db1c6f3a3..ce63d9a78 100644
--- a/src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java
+++ b/src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java
@@ -11,8 +11,8 @@ import com.mojang.brigadier.arguments.StringArgumentType;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.core.apis.IAPIEnvironment;
 import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.tracking.ComputerTracker;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.core.tracking.TrackingContext;
@@ -118,12 +118,12 @@ public final class CommandComputerCraft
                         table.row( header( "Position" ), linkPosition( context.getSource(), computer ) );
                         table.row( header( "Family" ), text( computer.getFamily().toString() ) );
 
-                        for( int i = 0; i < 6; i++ )
+                        for( ComputerSide side : ComputerSide.values() )
                         {
-                            IPeripheral peripheral = computer.getPeripheral( i );
+                            IPeripheral peripheral = computer.getPeripheral( side );
                             if( peripheral != null )
                             {
-                                table.row( header( "Peripheral " + IAPIEnvironment.SIDE_NAMES[i] ), text( peripheral.getType() ) );
+                                table.row( header( "Peripheral " + side.getName() ), text( peripheral.getType() ) );
                             }
                         }
 
diff --git a/src/main/java/dan200/computercraft/shared/command/Exceptions.java b/src/main/java/dan200/computercraft/shared/command/Exceptions.java
index a1a45b802..6773e39ea 100644
--- a/src/main/java/dan200/computercraft/shared/command/Exceptions.java
+++ b/src/main/java/dan200/computercraft/shared/command/Exceptions.java
@@ -16,7 +16,7 @@ public final class Exceptions
     public static final DynamicCommandExceptionType COMPUTER_ARG_NONE = translated1( "argument.computercraft.computer.no_matching" );
     public static final Dynamic2CommandExceptionType COMPUTER_ARG_MANY = translated2( "argument.computercraft.computer.many_matching" );
 
-    public static final DynamicCommandExceptionType TRACKING_FIELD_ARG_NONE = translated1( "argument.computercraft.tacking_field.no_field" );
+    public static final DynamicCommandExceptionType TRACKING_FIELD_ARG_NONE = translated1( "argument.computercraft.tracking_field.no_field" );
 
     static final SimpleCommandExceptionType NOT_TRACKING_EXCEPTION = translated( "commands.computercraft.track.stop.not_enabled" );
     static final SimpleCommandExceptionType NO_TIMINGS_EXCEPTION = translated( "commands.computercraft.track.dump.no_timings" );
diff --git a/src/main/java/dan200/computercraft/shared/computer/blocks/BlockComputerBase.java b/src/main/java/dan200/computercraft/shared/computer/blocks/BlockComputerBase.java
index ab7e2f48a..a63bf66ce 100644
--- a/src/main/java/dan200/computercraft/shared/computer/blocks/BlockComputerBase.java
+++ b/src/main/java/dan200/computercraft/shared/computer/blocks/BlockComputerBase.java
@@ -6,6 +6,7 @@
 
 package dan200.computercraft.shared.computer.blocks;
 
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.common.BlockGeneric;
 import dan200.computercraft.shared.common.IBundledRedstoneBlock;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -65,9 +66,8 @@ public abstract class BlockComputerBase<T extends TileComputerBase> extends Bloc
         ServerComputer computer = computerEntity.getServerComputer();
         if( computer == null ) return 0;
 
-        EnumFacing localSide = computerEntity.remapToLocalSide( incomingSide.getOpposite() );
-        return computerEntity.isRedstoneBlockedOnSide( localSide ) ? 0 :
-            computer.getRedstoneOutput( localSide.getIndex() );
+        ComputerSide localSide = computerEntity.remapToLocalSide( incomingSide.getOpposite() );
+        return computerEntity.isRedstoneBlockedOnSide( localSide ) ? 0 : computer.getRedstoneOutput( localSide );
     }
 
     @Nonnull
@@ -105,9 +105,8 @@ public abstract class BlockComputerBase<T extends TileComputerBase> extends Bloc
         ServerComputer computer = computerEntity.getServerComputer();
         if( computer == null ) return 0;
 
-        EnumFacing localSide = computerEntity.remapToLocalSide( side );
-        return computerEntity.isRedstoneBlockedOnSide( localSide ) ? 0 :
-            computer.getBundledRedstoneOutput( localSide.getIndex() );
+        ComputerSide localSide = computerEntity.remapToLocalSide( side );
+        return computerEntity.isRedstoneBlockedOnSide( localSide ) ? 0 : computer.getBundledRedstoneOutput( localSide );
     }
 
     @Nonnull
diff --git a/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java b/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java
index 6f132cd98..4af198b10 100644
--- a/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java
+++ b/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java
@@ -7,6 +7,7 @@
 package dan200.computercraft.shared.computer.blocks;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ComputerState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -95,8 +96,12 @@ public class TileComputer extends TileComputerBase
     }
 
     @Override
-    protected EnumFacing remapLocalSide( EnumFacing localSide )
+    protected ComputerSide remapLocalSide( ComputerSide localSide )
     {
-        return localSide.getAxis() == EnumFacing.Axis.X ? localSide.getOpposite() : localSide;
+        // For legacy reasons, computers invert the meaning of "left" and "right". A computer's front is facing
+        // towards you, but a turtle's front is facing the other way.
+        if( localSide == ComputerSide.RIGHT ) return ComputerSide.LEFT;
+        if( localSide == ComputerSide.LEFT ) return ComputerSide.RIGHT;
+        return localSide;
     }
 }
diff --git a/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java b/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java
index e50c9aa9d..0fe8c8a66 100644
--- a/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java
+++ b/src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java
@@ -9,6 +9,7 @@ package dan200.computercraft.shared.computer.blocks;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralTile;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.BundledRedstone;
 import dan200.computercraft.shared.Peripherals;
 import dan200.computercraft.shared.common.TileGeneric;
@@ -198,24 +199,24 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
         m_on = m_startOn = nbt.getBoolean( NBT_ON );
     }
 
-    protected boolean isPeripheralBlockedOnSide( EnumFacing localSide )
+    protected boolean isPeripheralBlockedOnSide( ComputerSide localSide )
     {
         return false;
     }
 
-    protected boolean isRedstoneBlockedOnSide( EnumFacing localSide )
+    protected boolean isRedstoneBlockedOnSide( ComputerSide localSide )
     {
         return false;
     }
 
     protected abstract EnumFacing getDirection();
 
-    protected EnumFacing remapToLocalSide( EnumFacing globalSide )
+    protected ComputerSide remapToLocalSide( EnumFacing globalSide )
     {
         return remapLocalSide( DirectionUtil.toLocal( getDirection(), globalSide ) );
     }
 
-    protected EnumFacing remapLocalSide( EnumFacing localSide )
+    protected ComputerSide remapLocalSide( ComputerSide localSide )
     {
         return localSide;
     }
@@ -223,15 +224,15 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
     private void updateSideInput( ServerComputer computer, EnumFacing dir, BlockPos offset )
     {
         EnumFacing offsetSide = dir.getOpposite();
-        EnumFacing localDir = remapToLocalSide( dir );
+        ComputerSide localDir = remapToLocalSide( dir );
         if( !isRedstoneBlockedOnSide( localDir ) )
         {
-            computer.setRedstoneInput( localDir.getIndex(), getWorld().getRedstonePower( offset, dir ) );
-            computer.setBundledRedstoneInput( localDir.getIndex(), BundledRedstone.getOutput( getWorld(), offset, offsetSide ) );
+            computer.setRedstoneInput( localDir, getWorld().getRedstonePower( offset, dir ) );
+            computer.setBundledRedstoneInput( localDir, BundledRedstone.getOutput( getWorld(), offset, offsetSide ) );
         }
         if( !isPeripheralBlockedOnSide( localDir ) )
         {
-            computer.setPeripheral( localDir.getIndex(), Peripherals.getPeripheral( getWorld(), offset, offsetSide ) );
+            computer.setPeripheral( localDir, Peripherals.getPeripheral( getWorld(), offset, offsetSide ) );
         }
     }
 
@@ -257,7 +258,6 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
         ServerComputer computer = getServerComputer();
         if( computer == null ) return;
 
-        // Find the appropriate side and update.
         BlockPos pos = computer.getPosition();
         for( EnumFacing dir : DirectionUtil.FACINGS )
         {
@@ -268,6 +268,9 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
                 break;
             }
         }
+
+        // If the position is not any adjacent one, update all inputs.
+        updateInput();
     }
 
     public void updateOutput()
diff --git a/src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java b/src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java
index 59d634823..7c5d727c1 100644
--- a/src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java
+++ b/src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java
@@ -14,6 +14,7 @@ import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.core.apis.IAPIEnvironment;
 import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.computer.IComputerEnvironment;
 import dan200.computercraft.shared.common.ServerTerminal;
 import dan200.computercraft.shared.network.NetworkHandler;
@@ -261,22 +262,22 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
         m_computer.queueEvent( event, arguments );
     }
 
-    public int getRedstoneOutput( int side )
+    public int getRedstoneOutput( ComputerSide side )
     {
         return m_computer.getEnvironment().getExternalRedstoneOutput( side );
     }
 
-    public void setRedstoneInput( int side, int level )
+    public void setRedstoneInput( ComputerSide side, int level )
     {
         m_computer.getEnvironment().setRedstoneInput( side, level );
     }
 
-    public int getBundledRedstoneOutput( int side )
+    public int getBundledRedstoneOutput( ComputerSide side )
     {
         return m_computer.getEnvironment().getExternalBundledRedstoneOutput( side );
     }
 
-    public void setBundledRedstoneInput( int side, int combination )
+    public void setBundledRedstoneInput( ComputerSide side, int combination )
     {
         m_computer.getEnvironment().setBundledRedstoneInput( side, combination );
     }
@@ -286,12 +287,12 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
         m_computer.addApi( api );
     }
 
-    public void setPeripheral( int side, IPeripheral peripheral )
+    public void setPeripheral( ComputerSide side, IPeripheral peripheral )
     {
         m_computer.getEnvironment().setPeripheral( side, peripheral );
     }
 
-    public IPeripheral getPeripheral( int side )
+    public IPeripheral getPeripheral( ComputerSide side )
     {
         return m_computer.getEnvironment().getPeripheral( side );
     }
diff --git a/src/main/java/dan200/computercraft/shared/pocket/core/PocketServerComputer.java b/src/main/java/dan200/computercraft/shared/pocket/core/PocketServerComputer.java
index f80505547..264de4d48 100644
--- a/src/main/java/dan200/computercraft/shared/pocket/core/PocketServerComputer.java
+++ b/src/main/java/dan200/computercraft/shared/pocket/core/PocketServerComputer.java
@@ -10,6 +10,7 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.pocket.IPocketAccess;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -123,14 +124,14 @@ public class PocketServerComputer extends ServerComputer implements IPocketAcces
     public void invalidatePeripheral()
     {
         IPeripheral peripheral = m_upgrade == null ? null : m_upgrade.createPeripheral( this );
-        setPeripheral( 2, peripheral );
+        setPeripheral( ComputerSide.BACK, peripheral );
     }
 
     @Nonnull
     @Override
     public Map<ResourceLocation, IPeripheral> getUpgrades()
     {
-        return m_upgrade == null ? Collections.emptyMap() : Collections.singletonMap( m_upgrade.getUpgradeID(), getPeripheral( 2 ) );
+        return m_upgrade == null ? Collections.emptyMap() : Collections.singletonMap( m_upgrade.getUpgradeID(), getPeripheral( ComputerSide.BACK ) );
     }
 
     public IPocketUpgrade getUpgrade()
diff --git a/src/main/java/dan200/computercraft/shared/pocket/items/ItemPocketComputer.java b/src/main/java/dan200/computercraft/shared/pocket/items/ItemPocketComputer.java
index 6cbf405f5..ab681c433 100644
--- a/src/main/java/dan200/computercraft/shared/pocket/items/ItemPocketComputer.java
+++ b/src/main/java/dan200/computercraft/shared/pocket/items/ItemPocketComputer.java
@@ -12,6 +12,7 @@ import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.PocketUpgrades;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.computer.core.ClientComputer;
@@ -120,7 +121,7 @@ public class ItemPocketComputer extends Item implements IComputerItem, IMedia, I
                 // Update pocket upgrade
                 if( upgrade != null )
                 {
-                    upgrade.update( computer, computer.getPeripheral( 2 ) );
+                    upgrade.update( computer, computer.getPeripheral( ComputerSide.BACK ) );
                 }
             }
         }
@@ -149,7 +150,7 @@ public class ItemPocketComputer extends Item implements IComputerItem, IMedia, I
                 if( upgrade != null )
                 {
                     computer.updateValues( player, stack, upgrade );
-                    stop = upgrade.onRightClick( world, computer, computer.getPeripheral( 2 ) );
+                    stop = upgrade.onRightClick( world, computer, computer.getPeripheral( ComputerSide.BACK ) );
                 }
             }
 
diff --git a/src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java b/src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java
index 50569ee1e..56b1b82d5 100644
--- a/src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java
+++ b/src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java
@@ -13,6 +13,7 @@ import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.shared.common.TileGeneric;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.computer.blocks.ComputerPeripheral;
 import dan200.computercraft.shared.computer.blocks.ComputerProxy;
 import dan200.computercraft.shared.computer.blocks.TileComputerBase;
@@ -324,13 +325,13 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     }
 
     @Override
-    protected boolean isPeripheralBlockedOnSide( EnumFacing localSide )
+    protected boolean isPeripheralBlockedOnSide( ComputerSide localSide )
     {
         return hasPeripheralUpgradeOnSide( localSide );
     }
 
     @Override
-    protected boolean isRedstoneBlockedOnSide( EnumFacing localSide )
+    protected boolean isRedstoneBlockedOnSide( ComputerSide localSide )
     {
         return false;
     }
@@ -568,15 +569,15 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
 
     // Privates
 
-    private boolean hasPeripheralUpgradeOnSide( EnumFacing side )
+    private boolean hasPeripheralUpgradeOnSide( ComputerSide side )
     {
         ITurtleUpgrade upgrade;
         switch( side )
         {
-            case WEST:
+            case RIGHT:
                 upgrade = getUpgrade( TurtleSide.Right );
                 break;
-            case EAST:
+            case LEFT:
                 upgrade = getUpgrade( TurtleSide.Left );
                 break;
             default:
diff --git a/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java b/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java
index b590838ae..36e219ceb 100644
--- a/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java
+++ b/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java
@@ -13,6 +13,7 @@ import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.turtle.*;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.TurtleUpgrades;
 import dan200.computercraft.shared.computer.blocks.ComputerProxy;
 import dan200.computercraft.shared.computer.blocks.TileComputerBase;
@@ -730,15 +731,15 @@ public class TurtleBrain implements ITurtleAccess
             : 0.0f;
     }
 
-    private static int toDirection( TurtleSide side )
+    private static ComputerSide toDirection( TurtleSide side )
     {
         switch( side )
         {
             case Left:
-                return 5;
+                return ComputerSide.LEFT;
             case Right:
             default:
-                return 4;
+                return ComputerSide.RIGHT;
         }
     }
 
diff --git a/src/main/java/dan200/computercraft/shared/util/DirectionUtil.java b/src/main/java/dan200/computercraft/shared/util/DirectionUtil.java
index a4d654fb4..cee516e4c 100644
--- a/src/main/java/dan200/computercraft/shared/util/DirectionUtil.java
+++ b/src/main/java/dan200/computercraft/shared/util/DirectionUtil.java
@@ -6,6 +6,7 @@
 
 package dan200.computercraft.shared.util;
 
+import dan200.computercraft.core.computer.ComputerSide;
 import net.minecraft.util.EnumFacing;
 
 public final class DirectionUtil
@@ -14,28 +15,16 @@ public final class DirectionUtil
 
     public static final EnumFacing[] FACINGS = EnumFacing.values();
 
-    public static EnumFacing toLocal( EnumFacing front, EnumFacing relative )
+    public static ComputerSide toLocal( EnumFacing front, EnumFacing dir )
     {
-        if( relative.getAxis() == EnumFacing.Axis.Y ) return relative;
-
         if( front.getAxis() == EnumFacing.Axis.Y ) front = EnumFacing.NORTH;
 
-        if( relative == front )
-        {
-            return EnumFacing.SOUTH;
-        }
-        else if( relative == front.getOpposite() )
-        {
-            return EnumFacing.NORTH;
-        }
-        else if( relative == front.rotateYCCW() )
-        {
-            return EnumFacing.EAST;
-        }
-        else
-        {
-            return EnumFacing.WEST;
-        }
+        if( dir == front ) return ComputerSide.FRONT;
+        if( dir == front.getOpposite() ) return ComputerSide.BACK;
+        if( dir == front.rotateYCCW() ) return ComputerSide.LEFT;
+        if( dir == front.rotateY() ) return ComputerSide.RIGHT;
+        if( dir == EnumFacing.UP ) return ComputerSide.TOP;
+        return ComputerSide.BOTTOM;
     }
 
     public static float toPitchAngle( EnumFacing dir )
diff --git a/src/main/java/dan200/computercraft/shared/util/RedstoneUtil.java b/src/main/java/dan200/computercraft/shared/util/RedstoneUtil.java
index 90ea40e91..86ed53269 100644
--- a/src/main/java/dan200/computercraft/shared/util/RedstoneUtil.java
+++ b/src/main/java/dan200/computercraft/shared/util/RedstoneUtil.java
@@ -10,22 +10,20 @@ import net.minecraft.block.state.IBlockState;
 import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
+import net.minecraftforge.event.ForgeEventFactory;
+
+import java.util.EnumSet;
 
 public final class RedstoneUtil
 {
     public static void propagateRedstoneOutput( World world, BlockPos pos, EnumFacing side )
     {
-        // Propagate ordinary output
+        // Propagate ordinary output. See BlockRedstoneDiode.notifyNeighbors
         IBlockState block = world.getBlockState( pos );
+        if( ForgeEventFactory.onNeighborNotify( world, pos, block, EnumSet.of( side ), false ).isCanceled() ) return;
+
         BlockPos neighbourPos = pos.offset( side );
-        IBlockState neighbour = world.getBlockState( neighbourPos );
-        if( !neighbour.isAir( world, pos ) )
-        {
-            world.neighborChanged( neighbourPos, block.getBlock(), pos );
-            if( neighbour.getBlock().isNormalCube( neighbour, world, neighbourPos ) )
-            {
-                world.notifyNeighborsOfStateExcept( neighbourPos, block.getBlock(), side.getOpposite() );
-            }
-        }
+        world.neighborChanged( neighbourPos, block.getBlock(), pos );
+        world.notifyNeighborsOfStateExcept( neighbourPos, block.getBlock(), side.getOpposite() );
     }
 }
diff --git a/src/main/resources/assets/computercraft/lang/de_de.json b/src/main/resources/assets/computercraft/lang/de_de.json
index 329d6d17b..14a8ae879 100644
--- a/src/main/resources/assets/computercraft/lang/de_de.json
+++ b/src/main/resources/assets/computercraft/lang/de_de.json
@@ -1,4 +1,5 @@
 {
+    "itemGroup.computercraft": "CC: Tweaked",
 
     "block.computercraft.computer_normal": "Computer",
     "block.computercraft.computer_advanced": "Erweiterter Computer",
@@ -50,6 +51,99 @@
     "chat.computercraft.wired_modem.peripheral_connected": "Peripheriegerät \"%s\" mit dem Netzwerk verbunden",
     "chat.computercraft.wired_modem.peripheral_disconnected": "Peripheriegerät \"%s\" vom Netzwerk getrennt",
 
+    "commands.computercraft.synopsis": "Verschiedene Befehle um Computer zu kontrollieren.",
+    "commands.computercraft.desc": "Der /computercraft Befehl enthält verschiedene Werkzeuge um Computer zu debuggen, kontrollieren oder mit ihnen zu interagieren.",
+
+    "commands.computercraft.help.synopsis": "Zeigt die Hilfe für den angegebenen Befehl",
+    "commands.computercraft.help.desc": "",
+    "commands.computercraft.help.no_children": "%s hat keine Unterbefehle",
+    "commands.computercraft.help.no_command": "Unbekannter Befehl '%s'",
+
+    "commands.computercraft.dump.synopsis": "Zeigt den Status eines Computers.",
+    "commands.computercraft.dump.desc": "Zeigt den Status aller Computer oder genauere Informationen über einen angegebenen Computer. Der Computer kann entweder über seine Instanz ID (z.B. 123), seine Computer ID (z.B. #123) oder seinen Namen (z.B. \"@Mein Computer\") angegeben werden.",
+    "commands.computercraft.dump.action": "Zeigt mehr Informationen über einen Computer",
+
+    "commands.computercraft.shutdown.synopsis": "Fährt den Computer aus der Ferne herunter.",
+    "commands.computercraft.shutdown.desc": "Fährt die angegebenen Computer herunter. Falls keine Computer angegeben sind, werden alle heruntergefahren. Der Computer kann entweder über seine Instanz ID (z.B. 123), seine Computer ID (z.B. #123) oder seinen Namen (z.B. \"@Mein Computer\") angegeben werden.",
+    "commands.computercraft.shutdown.done": "Fährt die Computer %s/%s herunter",
+
+    "commands.computercraft.turn_on.synopsis": "Fährt einen Computer aus der Ferne hoch.",
+    "commands.computercraft.turn_on.desc": "Fährt die angegebenen Computer hoch. Der Computer kann entweder über seine Instanz ID (z.B. 123), seine Computer ID (z.B. #123) oder seinen Namen (z.B. \"@Mein Computer\") angegeben werden.",
+    "commands.computercraft.turn_on.done": "Fährt die Computer %s/%s hoch",
+
+    "commands.computercraft.tp.synopsis": "Teleportiert dich zum angegebenen Computer.",
+    "commands.computercraft.tp.desc": "Teleportiert dich zum Standort eines Computers. Der Computer kann entweder über seine Instanz ID (z.B. 123), seine Computer ID (z.B. #123) oder seinen Namen (z.B. \"@Mein Computer\") angegeben werden.",
+    "commands.computercraft.tp.action": "Teleportiert dich zum Computer",
+    "commands.computercraft.tp.not_player": "Konnte Terminal für Nicht-Spieler nicht öffnen",
+    "commands.computercraft.tp.not_there": "Konnte Computer in der Welt nicht finden",
+
+    "commands.computercraft.view.synopsis": "Zeigt das Terminal eines Computers.",
+    "commands.computercraft.view.desc": "Zeigt das Terminal eines Computers. Dies ermöglicht, den Computer aus der Ferne zu steuern. Ein Zugriff auf das Inventar eines Turtles ist dadurch allerdings nicht möglich. Der Computer kann entweder über seine Instanz ID (z.B. 123), seine Computer ID (z.B. #123) oder seinen Namen (z.B. \"@Mein Computer\") angegeben werden.",
+    "commands.computercraft.view.action": "Zeigt den Computer",
+    "commands.computercraft.view.not_player": "Konnte Terminal für Nicht-Spieler nicht öffnen",
+
+    "commands.computercraft.track.synopsis": "Zeichnet die Laufzeiten von Computern auf.",
+    "commands.computercraft.track.desc": "Zeichnet die Laufzeiten von Computern und wie viele Events ausgelöst werden auf. Die Ausgabe der Informationen ist ähnlich zu /forge track, was beim aufspüren von Lags sehr hilfreich sein kann.",
+
+    "commands.computercraft.track.start.synopsis": "Startet die Aufzeichnung von Computern",
+    "commands.computercraft.track.start.desc": "Startet die Aufzeichnung der Laufzeiten und Anzahl der Events aller Computer. Dadurch werden die Ergebnisse der letzten Male verworfen.",
+    "commands.computercraft.track.start.stop": "Führe %s aus um die Aufzeichnung zu stoppen und die Ergebnisse anzusehen",
+
+    "commands.computercraft.track.stop.synopsis": "Stoppt die Aufzeichnung aller Computer",
+    "commands.computercraft.track.stop.desc": "Stopt die Aufzeichnung aller Computer Events und Laufzeiten",
+    "commands.computercraft.track.stop.action": "Klicke um die Aufzeichnung zu stoppen",
+    "commands.computercraft.track.stop.not_enabled": "Momentan werden keine Computer aufgezeichnet",
+
+    "commands.computercraft.track.dump.synopsis": "Gibt die aktuellen Ergebnisse der Aufzeichnung aus",
+    "commands.computercraft.track.dump.desc": "Gibt die aktuellen Ergebnisse der Aufzeichnung aus.",
+    "commands.computercraft.track.dump.no_timings": "Keine Zeitangaben verfügbar",
+    "commands.computercraft.track.dump.computer": "Computer",
+
+    "commands.computercraft.reload.synopsis": "Liest die Konfigurationsdatei von ComputerCraft neu ein",
+    "commands.computercraft.reload.desc": "Liest die Konfigurationsdatei von ComputerCraft neu ein",
+    "commands.computercraft.reload.done": "Die Konfigurationsdatei wurde erfolgreich neu eingelesen",
+
+    "commands.computercraft.queue.synopsis": "Sendet ein computer_command Event an einen Befehlscomputer",
+    "commands.computercraft.queue.desc": "Sendet ein computer_command Event zusammen mit optionalen Argumenten an einen Befehlscomputer. Dieser Befehl wurde als eine Computerfreundliche Version von /trigger für Mapdesigner designed. Jeder Spieler kann diesen Befehl ausführen, weshalb er sich perfekt für ein Klickevent von z.B. Schildern oder Büchern eignet.",
+
+    "commands.computercraft.generic.no_position": "<Keine Position>",
+    "commands.computercraft.generic.position": "%s, %s, %s",
+    "commands.computercraft.generic.yes": "J",
+    "commands.computercraft.generic.no": "N",
+    "commands.computercraft.generic.exception": "Unbehandelte Ausnahme (%s)",
+    "commands.computercraft.generic.additional_rows": "%d zusätzliche Zeilen…",
+
+    "argument.computercraft.computer.no_matching": "Kein Computer passt auf '%s'",
+    "argument.computercraft.computer.many_matching": "Mehrere Computer passen auf '%s' (Instanzen %s)",
+
+    "argument.computercraft.tracking_field.no_field": "Unbekanntes Feld '%s'",
+
+    "tracking_field.computercraft.tasks.name": "Aufgaben",
+    "tracking_field.computercraft.total.name": "Gesamtzeit",
+    "tracking_field.computercraft.average.name": "Durchschnittliche Zeit",
+    "tracking_field.computercraft.max.name": "Maximale Zeit",
+
+    "tracking_field.computercraft.server_count.name": "Anzahl der Server-Tasks",
+    "tracking_field.computercraft.server_time.name": "Server-Task-Zeit",
+
+    "tracking_field.computercraft.peripheral.name": "Peripheriegeräte Aufrufe",
+    "tracking_field.computercraft.fs.name": "Dateisystem Operationen",
+    "tracking_field.computercraft.turtle.name": "Turtle Operationen",
+
+    "tracking_field.computercraft.http.name": "HTTP-Requests",
+    "tracking_field.computercraft.http_upload.name": "HTTP Upload",
+    "tracking_field.computercraft.http_download.name": "HTTT Download",
+
+    "tracking_field.computercraft.websocket_incoming.name": "Websocket eingehend",
+    "tracking_field.computercraft.websocket_outgoing.name": "Websocket ausgehend",
+
+    "tracking_field.computercraft.coroutines_created.name": "Koroutinen erstellt",
+    "tracking_field.computercraft.coroutines_dead.name": "Koroutinen gelöscht",
+
+    "gui.computercraft.tooltip.copy": "In die Zwischenablage kopieren",
+    "gui.computercraft.tooltip.computer_id": "(Computer ID: %s)",
+    "gui.computercraft.tooltip.disk_id": "(Disketten ID: %s)",
+
     "gui.computercraft.config.computer_space_limit": "Speicherplatz von Computern (bytes)",
     "gui.computercraft.config.floppy_space_limit": "Speicherplatz von Disketten (bytes)",
     "gui.computercraft.config.maximum_open_files": "Maximalanzahl an gleichzeitig offenen Dateien je Computer",
@@ -58,11 +152,25 @@
     "gui.computercraft.config.debug_enabled": "Debug-Library aktivieren",
     "gui.computercraft.config.log_computer_errors": "Peripheriefehler loggen",
 
+    "gui.computercraft.config.execution": "Ausführung",
+    "gui.computercraft.config.execution.computer_threads": "Computer Threads",
+    "gui.computercraft.config.execution.max_main_global_time": "Globales Servertick Zeitlimit",
+    "gui.computercraft.config.execution.max_main_computer_time": "Computer Servertick Zeitlimit",
+
+    "gui.computercraft.config.http": "HTTP",
     "gui.computercraft.config.http.enabled": "HTTP-API aktivieren",
     "gui.computercraft.config.http.websocket_enabled": "HTTP-Websockets aktivieren",
     "gui.computercraft.config.http.whitelist": "HTTP-Whitelist",
     "gui.computercraft.config.http.blacklist": "HTTP-Blacklist",
 
+    "gui.computercraft.config.http.timeout": "Zeitüberschreitung",
+    "gui.computercraft.config.http.max_requests": "Maximale Anzahl gleichzeitiger Anfragen",
+    "gui.computercraft.config.http.max_download": "Maximale Antwortgröße",
+    "gui.computercraft.config.http.max_upload": "Maximale Anfragegröße",
+    "gui.computercraft.config.http.max_websockets": "Maximale Anzahl gleichzeitiger Websockets",
+    "gui.computercraft.config.http.max_websocket_message": "Maximale Größe der Websocket-Nachricht",
+
+    "gui.computercraft.config.peripheral": "Peripheriegeräte",
     "gui.computercraft.config.peripheral.command_block_enabled": "Befehlsblöcke als Peripheriegerät erlauben",
     "gui.computercraft.config.peripheral.modem_range": "Modemreichweite (normal)",
     "gui.computercraft.config.peripheral.modem_high_altitude_range": "Modemreichweite (in großer Höhe)",
@@ -70,6 +178,7 @@
     "gui.computercraft.config.peripheral.modem_high_altitude_range_during_storm": "Modemreichweite (in großer Höhe bei schlechtem Wetter)",
     "gui.computercraft.config.peripheral.max_notes_per_tick": "Maximalanzahl an Noten, die ein Computer gleichzeitig spielen kann",
 
+    "gui.computercraft.config.turtle": "Turtles",
     "gui.computercraft.config.turtle.need_fuel": "Treibstoffverbrauch aktivieren",
     "gui.computercraft.config.turtle.normal_fuel_limit": "Treibstofflimit von Turtles",
     "gui.computercraft.config.turtle.advanced_fuel_limit": "Treibstofflimit von Erweiterten Turtles",
diff --git a/src/main/resources/assets/computercraft/lang/en_us.json b/src/main/resources/assets/computercraft/lang/en_us.json
index 4c90acf02..22a5d1167 100644
--- a/src/main/resources/assets/computercraft/lang/en_us.json
+++ b/src/main/resources/assets/computercraft/lang/en_us.json
@@ -116,7 +116,7 @@
     "argument.computercraft.computer.no_matching": "No computers matching '%s'",
     "argument.computercraft.computer.many_matching": "Multiple computers matching '%s' (instances %s)",
 
-    "argument.computercraft.tacking_field.no_field": "Unknown field '%s'",
+    "argument.computercraft.tracking_field.no_field": "Unknown field '%s'",
 
     "argument.computercraft.argument_expected": "Argument expected",
 
diff --git a/src/test/resources/test-rom/spec/apis/colors_spec.lua b/src/test/resources/test-rom/spec/apis/colors_spec.lua
new file mode 100644
index 000000000..d1271b625
--- /dev/null
+++ b/src/test/resources/test-rom/spec/apis/colors_spec.lua
@@ -0,0 +1,43 @@
+describe("The colors library", function()
+    it("colors.combine", function()
+        expect(colors.combine(colors.red, colors.brown, colors.green)):equals(0x7000)
+    end)
+
+    describe("colors.subtract", function()
+        it("subtracts colours", function()
+            expect(colors.subtract(0x7000, colors.green)):equals(0x5000)
+            expect(colors.subtract(0x5000, colors.red)):equals(0x1000)
+        end)
+        it("does nothing when color is not present", function()
+            expect(colors.subtract(0x1000, colors.red)):equals(0x1000)
+        end)
+        it("accepts multiple arguments", function()
+            expect(colors.subtract(0x7000, colors.red, colors.green, colors.red)):equals(0x1000)
+        end)
+    end)
+
+    describe("colors.test", function()
+        it("returns true when present", function()
+            expect(colors.test(0x7000, colors.green)):equals(true)
+        end)
+        it("returns false when absent", function()
+            expect(colors.test(0x5000, colors.green)):equals(false)
+        end)
+        it("allows multiple colors", function()
+            expect(colors.test(0x7000, 0x5000)):equals(true)
+        end)
+    end)
+
+    it("colors.packRGB", function()
+        expect(colors.packRGB(0.3, 0.5, 0.6)):equals(0x4c7f99)
+    end)
+
+    it("colors.unpackRGB", function()
+        expect({ colors.unpackRGB(0x4c7f99) }):same { 0x4c / 0xFF, 0x7f / 0xFF, 0.6 }
+    end)
+
+    it("colors.rgb8", function()
+        expect(colors.rgb8(0.3, 0.5, 0.6)):equals(0x4c7f99)
+        expect({ colors.rgb8(0x4c7f99) }):same { 0x4c / 0xFF, 0x7f / 0xFF, 0.6 }
+    end)
+end )