diff --git a/src/main/java/jace/hardware/massStorage/DirectoryNode.java b/src/main/java/jace/hardware/massStorage/DirectoryNode.java
index 6024af5..73ab874 100644
--- a/src/main/java/jace/hardware/massStorage/DirectoryNode.java
+++ b/src/main/java/jace/hardware/massStorage/DirectoryNode.java
@@ -21,6 +21,7 @@ package jace.hardware.massStorage;
 import java.io.File;
 import java.io.FileFilter;
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Collections;
 import java.util.HashSet;
@@ -121,6 +122,7 @@ public class DirectoryNode extends DiskNode implements FileFilter {
 
     @Override
     public void readBlock(int block, byte[] buffer) throws IOException {
+        Arrays.fill(buffer, (byte) 0);
         checkFile();
         if (block == 0) {
             generateHeader(buffer);
@@ -128,7 +130,7 @@ public class DirectoryNode extends DiskNode implements FileFilter {
                 generateFileEntry(buffer, 4 + (i + 1) * FILE_ENTRY_SIZE, i);
             }
         } else {
-            generatePointers(buffer, additionalNodes.get(block-1).getBaseBlock(), block < (additionalNodes.size()-1) ? additionalNodes.get(block+1).getBaseBlock() : 0);
+            generatePointers(buffer, getNodeSequence(block-1).getBaseBlock(), getNodeSequence(block+1) != null ? getNodeSequence(block+1).getBaseBlock() : 0);
             int start = (block * 13) - 1;
             int end = start + 13;
             int offset = 4;
@@ -167,7 +169,7 @@ public class DirectoryNode extends DiskNode implements FileFilter {
      */
     @SuppressWarnings("static-access")
     private void generateHeader(byte[] buffer) {
-        generatePointers(buffer, 0, additionalNodes.size()>1 ? additionalNodes.get(1).getBaseBlock() : 0);
+        generatePointers(buffer, 0, getNodeSequence(1) == null ? 0 : getNodeSequence(1).getBaseBlock());
         // Directory header + name length
         // Volumme header = 0x0f0; Subdirectory header = 0x0e0
         buffer[4] = (byte) ((isRoot ? 0x0F0 : 0x0E0) | getName().length());
diff --git a/src/main/java/jace/hardware/massStorage/DiskNode.java b/src/main/java/jace/hardware/massStorage/DiskNode.java
index e44b839..6257280 100644
--- a/src/main/java/jace/hardware/massStorage/DiskNode.java
+++ b/src/main/java/jace/hardware/massStorage/DiskNode.java
@@ -115,6 +115,16 @@ public abstract class DiskNode {
         allocate();        
     }
 
+    public DiskNode getNodeSequence(int num) {
+        if (num == 0) {
+            return this;
+        } else if (num <= additionalNodes.size()) {
+            return additionalNodes.get(num-1);
+        } else {
+            return null;
+        }        
+    }
+    
     /**
      * @return the allocated
      */
diff --git a/src/main/java/jace/hardware/massStorage/FileNode.java b/src/main/java/jace/hardware/massStorage/FileNode.java
index d6893f2..6b36c44 100644
--- a/src/main/java/jace/hardware/massStorage/FileNode.java
+++ b/src/main/java/jace/hardware/massStorage/FileNode.java
@@ -194,7 +194,7 @@ public class FileNode extends DiskNode {
     private void generateIndex(byte[] buffer, int indexStart, int indexLimit) {
         Arrays.fill(buffer, (byte) 0);
         for (int i = indexStart, count = 0; count < 256 && i < indexLimit && i <= additionalNodes.size(); i++, count++) {
-            int base = additionalNodes.get(i-1).getBaseBlock();
+            int base = getNodeSequence(i).getBaseBlock();
             buffer[count] = (byte) (base & 0x0ff);
             buffer[count + 256] = (byte) (base >> 8);
         }