diff --git a/build.xml b/build.xml
index b9b3984..de64466 100644
--- a/build.xml
+++ b/build.xml
@@ -51,7 +51,7 @@
 
     <target name="macapp" depends="build">
 
-    <mkdir dir="tmp"/>
+        <mkdir dir="tmp"/>
 
         <jarbundler
             name="AudiobookRecorder"
@@ -92,7 +92,15 @@
         <launch4j configFile="dist/windows/windows.xml" outfile="AudiobookRecorder.exe" />
     </target>
 
-    <target name="dist" depends="macapp,winapp" />
+    <target name="linuxapp" depends="build">
+        <concat destfile="AudiobookRecorder.run" binary="true">
+            <file file="dist/linux/stub" />
+            <file file="AudiobookRecorder.jar" />
+        </concat>
+        <chmod perm="0755" file="AudiobookRecorder.run" />
+    </target>
+
+    <target name="dist" depends="macapp,winapp,linuxapp" />
 
     <target name="tag">
         <exec executable="git">
@@ -148,6 +156,15 @@
             <arg value="-f"/> <arg value="AudiobookRecorder.exe"/>
             <arg value="-n"/> <arg value="AudiobookRecorder.exe"/>
         </exec>
+        <echo>Uploading AudiobookRecorder.run</echo>
+        <exec executable="github-release">
+            <arg value="upload"/>
+            <arg value="-u"/> <arg value="MajenkoProjects"/>
+            <arg value="-r"/> <arg value="AudiobookRecorder"/>
+            <arg value="-t"/> <arg value="v${version}"/>
+            <arg value="-f"/> <arg value="AudiobookRecorder.run"/>
+            <arg value="-n"/> <arg value="AudiobookRecorder.run"/>
+        </exec>
     </target>
 
 </project>
diff --git a/src/uk/co/majenko/audiobookrecorder/AudiobookRecorder.java b/src/uk/co/majenko/audiobookrecorder/AudiobookRecorder.java
index 7e698e9..2dc077c 100644
--- a/src/uk/co/majenko/audiobookrecorder/AudiobookRecorder.java
+++ b/src/uk/co/majenko/audiobookrecorder/AudiobookRecorder.java
@@ -225,6 +225,7 @@ public class AudiobookRecorder extends JFrame {
 
 
         Options.loadPreferences();
+        CacheManager.setCacheSize(Options.getInteger("cache.size"));
 
         setLayout(new BorderLayout());
 
@@ -495,18 +496,30 @@ public class AudiobookRecorder extends JFrame {
         centralPanel.getActionMap().put("startRecord", new AbstractAction() {
             public void actionPerformed(ActionEvent e) {
                 if (bookTree.isEditing()) return;
+                if (getNoiseFloor() == 0) {
+                    alertNoRoomNoise();
+                    return;
+                }
                 startRecording();
             }
         });
         centralPanel.getActionMap().put("startRecordNewPara", new AbstractAction() {
             public void actionPerformed(ActionEvent e) {
                 if (bookTree.isEditing()) return;
+                if (getNoiseFloor() == 0) {
+                    alertNoRoomNoise();
+                    return;
+                }
                 startRecordingNewParagraph();
             }
         });
         centralPanel.getActionMap().put("startRerecord", new AbstractAction() {
             public void actionPerformed(ActionEvent e) {
                 if (bookTree.isEditing()) return;
+                if (getNoiseFloor() == 0) {
+                    alertNoRoomNoise();
+                    return;
+                }
                 startReRecording();
             }
         });
@@ -559,6 +572,8 @@ public class AudiobookRecorder extends JFrame {
         } catch (Exception e) {
             e.printStackTrace();
         }
+
+
         AudiobookRecorder frame = new AudiobookRecorder();
     }
 
@@ -1554,6 +1569,10 @@ public class AudiobookRecorder extends JFrame {
     public void playFromSelectedSentence() {
         if (selectedSentence == null) return;
         if (playing != null) return;
+        if (getNoiseFloor() == 0) {
+            alertNoRoomNoise();
+            return;
+        }
         playing = selectedSentence;
         toolBar.disableSentence();
         toolBar.enableStop();
@@ -1649,4 +1668,8 @@ public class AudiobookRecorder extends JFrame {
         }
         playing = null;
     }
+
+    public void alertNoRoomNoise() {
+        JOptionPane.showMessageDialog(this, "You must record room noise\nbefore recording or playback", "Error", JOptionPane.ERROR_MESSAGE);
+    }
 }
diff --git a/src/uk/co/majenko/audiobookrecorder/CacheManager.java b/src/uk/co/majenko/audiobookrecorder/CacheManager.java
new file mode 100644
index 0000000..428d20e
--- /dev/null
+++ b/src/uk/co/majenko/audiobookrecorder/CacheManager.java
@@ -0,0 +1,28 @@
+package uk.co.majenko.audiobookrecorder;
+
+import java.util.*;
+
+public class CacheManager {
+    static ArrayList<Cacheable> cache = new ArrayList<Cacheable>();
+
+    static int cacheSize = 10;
+
+    public static void addToCache(Cacheable c) {
+        while (cache.size() >= cacheSize) {
+            Cacheable ob = cache.remove(0);
+            if (ob.lockedInCache()) {
+                cache.add(ob);
+            } else {
+                ob.clearCache();
+                System.err.println("Purged " + ob);
+            }
+        }
+
+        cache.add(c);
+        System.err.println("Cached " + c);
+    }
+
+    public static void setCacheSize(int c) {
+        cacheSize = c;
+    }
+}
diff --git a/src/uk/co/majenko/audiobookrecorder/Cacheable.java b/src/uk/co/majenko/audiobookrecorder/Cacheable.java
new file mode 100644
index 0000000..99d90e8
--- /dev/null
+++ b/src/uk/co/majenko/audiobookrecorder/Cacheable.java
@@ -0,0 +1,6 @@
+package uk.co.majenko.audiobookrecorder;
+
+public interface Cacheable {
+    public abstract void clearCache();
+    public abstract boolean lockedInCache();
+}
diff --git a/src/uk/co/majenko/audiobookrecorder/Options.java b/src/uk/co/majenko/audiobookrecorder/Options.java
index 4d609ee..d6d7afb 100644
--- a/src/uk/co/majenko/audiobookrecorder/Options.java
+++ b/src/uk/co/majenko/audiobookrecorder/Options.java
@@ -26,6 +26,7 @@ public class Options extends JDialog {
     JComboBox<KVPair> bitRate;
     JComboBox<KVPair> exportRate;
     JCheckBox enableParsing;
+    JSpinner cacheSize;
 
 
     static HashMap<String, String> defaultPrefs;
@@ -260,6 +261,9 @@ public class Options extends JDialog {
 
         addSeparator();
 
+        cacheSize = addSpinner("Cache size:", 0, 5000, 1, getInteger("cache.size"), "");
+
+        addSeparator();
 
         setTitle("Options");
 
@@ -427,6 +431,8 @@ public class Options extends JDialog {
 
         defaultPrefs.put("process.sphinx", "false");
 
+        defaultPrefs.put("cache.size", "100");
+
         if (prefs == null) {
             prefs = Preferences.userNodeForPackage(AudiobookRecorder.class);
         }
@@ -487,6 +493,7 @@ public class Options extends JDialog {
         set("audio.export.bitrate", ((KVPair)bitRate.getSelectedItem()).key);
         set("audio.export.samplerate", ((KVPair)exportRate.getSelectedItem()).key);
         set("process.sphinx", enableParsing.isSelected() ? "true" : "false");
+        set("cache.size", "" + cacheSize.getValue());
 
         savePreferences();
     }
diff --git a/src/uk/co/majenko/audiobookrecorder/Sentence.java b/src/uk/co/majenko/audiobookrecorder/Sentence.java
index a64b7cf..abd7500 100644
--- a/src/uk/co/majenko/audiobookrecorder/Sentence.java
+++ b/src/uk/co/majenko/audiobookrecorder/Sentence.java
@@ -13,7 +13,7 @@ import edu.cmu.sphinx.api.*;
 import edu.cmu.sphinx.decoder.adaptation.*;
 import edu.cmu.sphinx.result.*;
 
-public class Sentence extends DefaultMutableTreeNode {
+public class Sentence extends DefaultMutableTreeNode implements Cacheable {
     
     String text;
     String id;
@@ -33,6 +33,8 @@ public class Sentence extends DefaultMutableTreeNode {
     AudioInputStream inputStream;
 
     Thread recordingThread = null;
+
+    int[] storedAudioData = null;
     
     public Sentence() {
         super("");
@@ -119,6 +121,7 @@ public class Sentence extends DefaultMutableTreeNode {
             e.printStackTrace();
         }
         recording = false;
+        storedAudioData = null;
 
         if (!id.equals("room-noise")) {
             autoTrimSampleFFT();
@@ -306,6 +309,9 @@ public class Sentence extends DefaultMutableTreeNode {
     }
 
     public int[] getAudioData() {
+        if (storedAudioData != null) {
+            return storedAudioData;
+        }
         File f = getFile();
         try {
             AudioInputStream s = AudioSystem.getAudioInputStream(f);
@@ -335,6 +341,8 @@ public class Sentence extends DefaultMutableTreeNode {
             }
             s.close();
             sampleSize = samples.length;
+            storedAudioData = samples;
+            CacheManager.addToCache(this);
             return samples;
         } catch (Exception e) {
         }
@@ -530,4 +538,12 @@ public class Sentence extends DefaultMutableTreeNode {
     public boolean isInSample() { 
         return inSample;
     }
+
+    public void clearCache() {
+        storedAudioData = null;
+    }
+
+    public boolean lockedInCache() {
+        return id.equals("room-noise"); 
+    }
 }