diff --git a/src/com/bytezone/diskbrowser/disk/DiskFactory.java b/src/com/bytezone/diskbrowser/disk/DiskFactory.java
index 806564a..e68a496 100755
--- a/src/com/bytezone/diskbrowser/disk/DiskFactory.java
+++ b/src/com/bytezone/diskbrowser/disk/DiskFactory.java
@@ -152,7 +152,7 @@ public class DiskFactory
         System.out.println (" ** sdk **");
       try
       {
-        NuFX nuFX = new NuFX (file);
+        NuFX nuFX = new NuFX (file.toPath ());
         File tmp = File.createTempFile ("sdk", null);
         FileOutputStream fos = new FileOutputStream (tmp);
         fos.write (nuFX.getBuffer ());
diff --git a/src/com/bytezone/diskbrowser/utilities/Header.java b/src/com/bytezone/diskbrowser/utilities/Header.java
new file mode 100644
index 0000000..5a1022c
--- /dev/null
+++ b/src/com/bytezone/diskbrowser/utilities/Header.java
@@ -0,0 +1,96 @@
+package com.bytezone.diskbrowser.utilities;
+
+// -----------------------------------------------------------------------------------//
+class Header
+// -----------------------------------------------------------------------------------//
+{
+  private final int totalRecords;
+  private final int version;
+  private final int eof;
+  private final int crc;
+  private final DateTime created;
+  private final DateTime modified;
+  boolean bin2;
+
+  // ---------------------------------------------------------------------------------//
+  public Header (byte[] buffer) throws FileFormatException
+  // ---------------------------------------------------------------------------------//
+  {
+    int ptr = 0;
+
+    while (true)
+    {
+      if (isNuFile (buffer, ptr))
+        break;
+
+      if (isBin2 (buffer, ptr))
+      {
+        ptr += 128;
+        bin2 = true;
+        continue;
+      }
+
+      throw new FileFormatException ("NuFile not found");
+    }
+
+    crc = Utility.getWord (buffer, ptr + 6);
+    totalRecords = Utility.getLong (buffer, ptr + 8);
+    created = new DateTime (buffer, ptr + 12);
+    modified = new DateTime (buffer, ptr + 20);
+    version = Utility.getWord (buffer, ptr + 28);
+    eof = Utility.getLong (buffer, ptr + 38);
+
+    byte[] crcBuffer = new byte[40];
+    System.arraycopy (buffer, ptr + 8, crcBuffer, 0, crcBuffer.length);
+    if (crc != Utility.getCRC (crcBuffer, 0))
+    {
+      System.out.println ("***** Master CRC mismatch *****");
+      throw new FileFormatException ("Master CRC failed");
+    }
+  }
+
+  // ---------------------------------------------------------------------------------//
+  int getTotalRecords ()
+  // ---------------------------------------------------------------------------------//
+  {
+    return totalRecords;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  private boolean isNuFile (byte[] buffer, int ptr)
+  // ---------------------------------------------------------------------------------//
+  {
+    if (buffer[ptr] == 0x4E && buffer[ptr + 1] == (byte) 0xF5 && buffer[ptr + 2] == 0x46
+        && buffer[ptr + 3] == (byte) 0xE9 && buffer[ptr + 4] == 0x6C
+        && buffer[ptr + 5] == (byte) 0xE5)
+      return true;
+    return false;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  private boolean isBin2 (byte[] buffer, int ptr)
+  // ---------------------------------------------------------------------------------//
+  {
+    if (buffer[ptr] == 0x0A && buffer[ptr + 1] == 0x47 && buffer[ptr + 2] == 0x4C
+        && buffer[ptr + 18] == (byte) 0x02)
+      return true;
+    return false;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  @Override
+  public String toString ()
+  // ---------------------------------------------------------------------------------//
+  {
+    StringBuilder text = new StringBuilder ();
+
+    text.append (String.format ("Master CRC ..... %,d  (%04X)%n", crc, crc));
+    text.append (String.format ("Records ........ %,d%n", totalRecords));
+    text.append (String.format ("Created ........ %s%n", created.format ()));
+    text.append (String.format ("Modified ....... %s%n", modified.format ()));
+    text.append (String.format ("Version ........ %,d%n", version));
+    text.append (String.format ("Master EOF ..... %,d", eof));
+
+    return text.toString ();
+  }
+}
diff --git a/src/com/bytezone/diskbrowser/utilities/LZW.java b/src/com/bytezone/diskbrowser/utilities/LZW.java
index 4ca0cbf..01a41ec 100644
--- a/src/com/bytezone/diskbrowser/utilities/LZW.java
+++ b/src/com/bytezone/diskbrowser/utilities/LZW.java
@@ -118,7 +118,7 @@ class LZW
     for (byte[] track : chunks)
       System.arraycopy (track, 0, buffer, trackNumber++ * TRACK_LENGTH, TRACK_LENGTH);
 
-    if (crc != NuFX.getCRC (buffer, crcBase))
+    if (crc != Utility.getCRC (buffer, crcBase))
       System.out.println ("\n*** LZW CRC mismatch ***");
 
     return buffer;
diff --git a/src/com/bytezone/diskbrowser/utilities/NuFX.java b/src/com/bytezone/diskbrowser/utilities/NuFX.java
index e786b4b..9c3a091 100644
--- a/src/com/bytezone/diskbrowser/utilities/NuFX.java
+++ b/src/com/bytezone/diskbrowser/utilities/NuFX.java
@@ -1,6 +1,5 @@
 package com.bytezone.diskbrowser.utilities;
 
-import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -11,10 +10,6 @@ import java.util.List;
 public class NuFX
 // -----------------------------------------------------------------------------------//
 {
-  private static String[] fileSystems =
-      { "", "ProDOS/SOS", "DOS 3.3", "DOS 3.2", "Apple II Pascal", "Macintosh HFS",
-        "Macintosh MFS", "Lisa File System", "Apple CP/M", "", "MS-DOS", "High Sierra",
-        "ISO 9660", "AppleShare" };
   private Header header;
   private final byte[] buffer;
   private final boolean debug = false;
@@ -30,14 +25,6 @@ public class NuFX
     readBuffer ();
   }
 
-  // ---------------------------------------------------------------------------------//
-  public NuFX (File file) throws FileFormatException, IOException
-  // ---------------------------------------------------------------------------------//
-  {
-    buffer = Files.readAllBytes (file.toPath ());
-    readBuffer ();
-  }
-
   // ---------------------------------------------------------------------------------//
   private void readBuffer ()
   // ---------------------------------------------------------------------------------//
@@ -51,19 +38,19 @@ public class NuFX
     if (debug)
       System.out.printf ("%s%n%n", header);
 
-    for (int rec = 0; rec < header.totalRecords; rec++)
+    for (int rec = 0; rec < header.getTotalRecords (); rec++)
     {
-      Record record = new Record (dataPtr);
+      Record record = new Record (buffer, dataPtr);
       records.add (record);
 
       if (debug)
         System.out.printf ("Record: %d%n%n%s%n%n", rec, record);
 
-      dataPtr += record.attributes + record.fileNameLength;
+      dataPtr += record.getAttributes () + record.getFileNameLength ();
       int threadsPtr = dataPtr;
-      dataPtr += record.totThreads * 16;
+      dataPtr += record.getTotalThreads () * 16;
 
-      for (int i = 0; i < record.totThreads; i++)
+      for (int i = 0; i < record.getTotalThreads (); i++)
       {
         Thread thread = new Thread (buffer, threadsPtr + i * 16, dataPtr);
         threads.add (thread);
@@ -95,202 +82,4 @@ public class NuFX
         return thread.toString ();
     return "no disk";
   }
-
-  // ---------------------------------------------------------------------------------//
-  protected static int getCRC (final byte[] buffer, int base)
-  // ---------------------------------------------------------------------------------//
-  {
-    int crc = base;
-    for (int j = 0; j < buffer.length; j++)
-    {
-      crc = ((crc >>> 8) | (crc << 8)) & 0xFFFF;
-      crc ^= (buffer[j] & 0xFF);
-      crc ^= ((crc & 0xFF) >>> 4);
-      crc ^= (crc << 12) & 0xFFFF;
-      crc ^= ((crc & 0xFF) << 5) & 0xFFFF;
-    }
-
-    crc &= 0xFFFF;
-    return crc;
-  }
-
-  // ---------------------------------------------------------------------------------//
-  class Header
-  // ---------------------------------------------------------------------------------//
-  {
-    private final int totalRecords;
-    private final int version;
-    private final int eof;
-    private final int crc;
-    private final DateTime created;
-    private final DateTime modified;
-    boolean bin2;
-
-    public Header (byte[] buffer) throws FileFormatException
-    {
-      int ptr = 0;
-
-      while (true)
-      {
-        if (isNuFile (buffer, ptr))
-          break;
-
-        if (isBin2 (buffer, ptr))
-        {
-          ptr += 128;
-          bin2 = true;
-          continue;
-        }
-
-        throw new FileFormatException ("NuFile not found");
-      }
-
-      crc = Utility.getWord (buffer, ptr + 6);
-      totalRecords = Utility.getLong (buffer, ptr + 8);
-      created = new DateTime (buffer, ptr + 12);
-      modified = new DateTime (buffer, ptr + 20);
-      version = Utility.getWord (buffer, ptr + 28);
-      eof = Utility.getLong (buffer, ptr + 38);
-
-      byte[] crcBuffer = new byte[40];
-      System.arraycopy (buffer, ptr + 8, crcBuffer, 0, crcBuffer.length);
-      if (crc != getCRC (crcBuffer, 0))
-      {
-        System.out.println ("***** Master CRC mismatch *****");
-        throw new FileFormatException ("Master CRC failed");
-      }
-    }
-
-    private boolean isNuFile (byte[] buffer, int ptr)
-    {
-      if (buffer[ptr] == 0x4E && buffer[ptr + 1] == (byte) 0xF5 && buffer[ptr + 2] == 0x46
-          && buffer[ptr + 3] == (byte) 0xE9 && buffer[ptr + 4] == 0x6C
-          && buffer[ptr + 5] == (byte) 0xE5)
-        return true;
-      return false;
-    }
-
-    private boolean isBin2 (byte[] buffer, int ptr)
-    {
-      if (buffer[ptr] == 0x0A && buffer[ptr + 1] == 0x47 && buffer[ptr + 2] == 0x4C
-          && buffer[ptr + 18] == (byte) 0x02)
-        return true;
-      return false;
-    }
-
-    @Override
-    public String toString ()
-    {
-      StringBuilder text = new StringBuilder ();
-
-      text.append (String.format ("Master CRC ..... %,d  (%04X)%n", crc, crc));
-      text.append (String.format ("Records ........ %,d%n", totalRecords));
-      text.append (String.format ("Created ........ %s%n", created.format ()));
-      text.append (String.format ("Modified ....... %s%n", modified.format ()));
-      text.append (String.format ("Version ........ %,d%n", version));
-      text.append (String.format ("Master EOF ..... %,d", eof));
-
-      return text.toString ();
-    }
-  }
-
-  // ---------------------------------------------------------------------------------//
-  class Record
-  // ---------------------------------------------------------------------------------//
-  {
-    private final int totThreads;
-    private final int crc;
-    private final char separator;
-    private final int fileSystemID;
-    private final int attributes;
-    private final int version;
-    private final int access;
-    private final int fileType;
-    private final int auxType;
-    private final int storType;
-    private final DateTime created;
-    private final DateTime modified;
-    private final DateTime archived;
-    private final int optionSize;
-    private final int fileNameLength;
-    private final String fileName;
-
-    public Record (int dataPtr) throws FileFormatException
-    {
-      // check for NuFX
-      if (!isNuFX (buffer, dataPtr))
-        throw new FileFormatException ("NuFX not found");
-
-      crc = Utility.getWord (buffer, dataPtr + 4);
-      attributes = Utility.getWord (buffer, dataPtr + 6);
-      version = Utility.getWord (buffer, dataPtr + 8);
-      totThreads = Utility.getLong (buffer, dataPtr + 10);
-      fileSystemID = Utility.getWord (buffer, dataPtr + 14);
-      separator = (char) (buffer[dataPtr + 16] & 0x00FF);
-      access = Utility.getLong (buffer, dataPtr + 18);
-      fileType = Utility.getLong (buffer, dataPtr + 22);
-      auxType = Utility.getLong (buffer, dataPtr + 26);
-      storType = Utility.getWord (buffer, dataPtr + 30);
-      created = new DateTime (buffer, dataPtr + 32);
-      modified = new DateTime (buffer, dataPtr + 40);
-      archived = new DateTime (buffer, dataPtr + 48);
-      optionSize = Utility.getWord (buffer, dataPtr + 56);
-      fileNameLength = Utility.getWord (buffer, dataPtr + attributes - 2);
-
-      int len = attributes + fileNameLength - 6;
-      byte[] crcBuffer = new byte[len + totThreads * 16];
-      System.arraycopy (buffer, dataPtr + 6, crcBuffer, 0, crcBuffer.length);
-
-      if (crc != getCRC (crcBuffer, 0))
-      {
-        System.out.println ("***** Header CRC mismatch *****");
-        throw new FileFormatException ("Header CRC failed");
-      }
-
-      if (fileNameLength > 0)
-      {
-        int start = dataPtr + attributes;
-        int end = start + fileNameLength;
-        for (int i = start; i < end; i++)
-          buffer[i] &= 0x7F;
-        fileName = new String (buffer, start, fileNameLength);
-      }
-      else
-        fileName = "";
-    }
-
-    private boolean isNuFX (byte[] buffer, int ptr)
-    {
-      if (buffer[ptr] == 0x4E && buffer[ptr + 1] == (byte) 0xF5 && buffer[ptr + 2] == 0x46
-          && buffer[ptr + 3] == (byte) 0xD8)
-        return true;
-      return false;
-    }
-
-    @Override
-    public String toString ()
-    {
-      StringBuilder text = new StringBuilder ();
-
-      text.append (String.format ("Header CRC ..... %,d  (%04X)%n", crc, crc));
-      text.append (String.format ("Attributes ..... %d%n", attributes));
-      text.append (String.format ("Version ........ %d%n", version));
-      text.append (String.format ("Threads ........ %d%n", totThreads));
-      text.append (String.format ("File sys id .... %d (%s)%n", fileSystemID,
-          fileSystems[fileSystemID]));
-      text.append (String.format ("Separator ...... %s%n", separator));
-      text.append (String.format ("Access ......... %,d%n", access));
-      text.append (String.format ("File type ...... %,d%n", fileType));
-      text.append (String.format ("Aux type ....... %,d%n", auxType));
-      text.append (String.format ("Stor type ...... %,d%n", storType));
-      text.append (String.format ("Created ........ %s%n", created.format ()));
-      text.append (String.format ("Modified ....... %s%n", modified.format ()));
-      text.append (String.format ("Archived ....... %s%n", archived.format ()));
-      text.append (String.format ("Option size .... %,d%n", optionSize));
-      text.append (String.format ("Filename len ... %,d%n", fileNameLength));
-      text.append (String.format ("Filename ....... %s", fileName));
-
-      return text.toString ();
-    }
-  }
 }
\ No newline at end of file
diff --git a/src/com/bytezone/diskbrowser/utilities/Record.java b/src/com/bytezone/diskbrowser/utilities/Record.java
new file mode 100644
index 0000000..7879e6d
--- /dev/null
+++ b/src/com/bytezone/diskbrowser/utilities/Record.java
@@ -0,0 +1,133 @@
+package com.bytezone.diskbrowser.utilities;
+
+// -----------------------------------------------------------------------------------//
+class Record
+// -----------------------------------------------------------------------------------//
+{
+  private static String[] fileSystems =
+      { "", "ProDOS/SOS", "DOS 3.3", "DOS 3.2", "Apple II Pascal", "Macintosh HFS",
+        "Macintosh MFS", "Lisa File System", "Apple CP/M", "", "MS-DOS", "High Sierra",
+        "ISO 9660", "AppleShare" };
+
+  private final int totThreads;
+  private final int crc;
+  private final char separator;
+  private final int fileSystemID;
+  private final int attributes;
+  private final int version;
+  private final int access;
+  private final int fileType;
+  private final int auxType;
+  private final int storType;
+  private final DateTime created;
+  private final DateTime modified;
+  private final DateTime archived;
+  private final int optionSize;
+  private final int fileNameLength;
+  private final String fileName;
+
+  // ---------------------------------------------------------------------------------//
+  public Record (byte[] buffer, int dataPtr) throws FileFormatException
+  // ---------------------------------------------------------------------------------//
+  {
+    // check for NuFX
+    if (!isNuFX (buffer, dataPtr))
+      throw new FileFormatException ("NuFX not found");
+
+    crc = Utility.getWord (buffer, dataPtr + 4);
+    attributes = Utility.getWord (buffer, dataPtr + 6);
+    version = Utility.getWord (buffer, dataPtr + 8);
+    totThreads = Utility.getLong (buffer, dataPtr + 10);
+    fileSystemID = Utility.getWord (buffer, dataPtr + 14);
+    separator = (char) (buffer[dataPtr + 16] & 0x00FF);
+    access = Utility.getLong (buffer, dataPtr + 18);
+    fileType = Utility.getLong (buffer, dataPtr + 22);
+    auxType = Utility.getLong (buffer, dataPtr + 26);
+    storType = Utility.getWord (buffer, dataPtr + 30);
+    created = new DateTime (buffer, dataPtr + 32);
+    modified = new DateTime (buffer, dataPtr + 40);
+    archived = new DateTime (buffer, dataPtr + 48);
+    optionSize = Utility.getWord (buffer, dataPtr + 56);
+    fileNameLength = Utility.getWord (buffer, dataPtr + attributes - 2);
+
+    int len = attributes + fileNameLength - 6;
+    byte[] crcBuffer = new byte[len + totThreads * 16];
+    System.arraycopy (buffer, dataPtr + 6, crcBuffer, 0, crcBuffer.length);
+
+    if (crc != Utility.getCRC (crcBuffer, 0))
+    {
+      System.out.println ("***** Header CRC mismatch *****");
+      throw new FileFormatException ("Header CRC failed");
+    }
+
+    if (fileNameLength > 0)
+    {
+      int start = dataPtr + attributes;
+      int end = start + fileNameLength;
+      for (int i = start; i < end; i++)
+        buffer[i] &= 0x7F;
+      fileName = new String (buffer, start, fileNameLength);
+    }
+    else
+      fileName = "";
+  }
+
+  // ---------------------------------------------------------------------------------//
+  private boolean isNuFX (byte[] buffer, int ptr)
+  // ---------------------------------------------------------------------------------//
+  {
+    if (buffer[ptr] == 0x4E && buffer[ptr + 1] == (byte) 0xF5 && buffer[ptr + 2] == 0x46
+        && buffer[ptr + 3] == (byte) 0xD8)
+      return true;
+    return false;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  int getAttributes ()
+  // ---------------------------------------------------------------------------------//
+  {
+    return attributes;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  int getFileNameLength ()
+  // ---------------------------------------------------------------------------------//
+  {
+    return fileNameLength;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  int getTotalThreads ()
+  // ---------------------------------------------------------------------------------//
+  {
+    return totThreads;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  @Override
+  public String toString ()
+  // ---------------------------------------------------------------------------------//
+  {
+    StringBuilder text = new StringBuilder ();
+
+    text.append (String.format ("Header CRC ..... %,d  (%04X)%n", crc, crc));
+    text.append (String.format ("Attributes ..... %d%n", attributes));
+    text.append (String.format ("Version ........ %d%n", version));
+    text.append (String.format ("Threads ........ %d%n", totThreads));
+    text.append (String.format ("File sys id .... %d (%s)%n", fileSystemID,
+        fileSystems[fileSystemID]));
+    text.append (String.format ("Separator ...... %s%n", separator));
+    text.append (String.format ("Access ......... %,d%n", access));
+    text.append (String.format ("File type ...... %,d%n", fileType));
+    text.append (String.format ("Aux type ....... %,d%n", auxType));
+    text.append (String.format ("Stor type ...... %,d%n", storType));
+    text.append (String.format ("Created ........ %s%n", created.format ()));
+    text.append (String.format ("Modified ....... %s%n", modified.format ()));
+    text.append (String.format ("Archived ....... %s%n", archived.format ()));
+    text.append (String.format ("Option size .... %,d%n", optionSize));
+    text.append (String.format ("Filename len ... %,d%n", fileNameLength));
+    text.append (String.format ("Filename ....... %s", fileName));
+
+    return text.toString ();
+  }
+}
diff --git a/src/com/bytezone/diskbrowser/utilities/Utility.java b/src/com/bytezone/diskbrowser/utilities/Utility.java
index f008858..b8fbe0b 100644
--- a/src/com/bytezone/diskbrowser/utilities/Utility.java
+++ b/src/com/bytezone/diskbrowser/utilities/Utility.java
@@ -365,6 +365,24 @@ public class Utility
     return checksum.getValue ();
   }
 
+  // ---------------------------------------------------------------------------------//
+  protected static int getCRC (final byte[] buffer, int base)
+  // ---------------------------------------------------------------------------------//
+  {
+    int crc = base;
+    for (int j = 0; j < buffer.length; j++)
+    {
+      crc = ((crc >>> 8) | (crc << 8)) & 0xFFFF;
+      crc ^= (buffer[j] & 0xFF);
+      crc ^= ((crc & 0xFF) >>> 4);
+      crc ^= (crc << 12) & 0xFFFF;
+      crc ^= ((crc & 0xFF) << 5) & 0xFFFF;
+    }
+
+    crc &= 0xFFFF;
+    return crc;
+  }
+
   // ---------------------------------------------------------------------------------//
   public static int crc32 (byte[] buffer, int offset, int length)
   // ---------------------------------------------------------------------------------//