diff --git a/filesystem/iso9660/ByteParser.java b/filesystem/iso9660/ByteParser.java
new file mode 100644
index 0000000..4adc7fd
--- /dev/null
+++ b/filesystem/iso9660/ByteParser.java
@@ -0,0 +1,43 @@
+package filesystem.iso9660;
+
+public class ByteParser {
+    byte[] array;
+    int offset;
+
+    public ByteParser(byte[] array, int offset) {
+        this.array = array;
+        this.offset = offset;
+    }
+
+    public static int shortLE(int i0, int i1) {
+        return ((i1 << 8)
+              | (i0 << 0));
+    }
+
+    public static int intLE(int i0, int i1, int i2, int i3) {
+        return ((i3 << 24)
+              | (i2 << 16)
+              | (i1 << 8)
+              | (i0 << 0));
+    }
+
+    public int getByte(int pos) {
+        return array[offset + pos];
+    }
+
+    public int getShortLE(int pos) {
+        int i0 = array[offset + pos + 0];
+        int i1 = array[offset + pos + 1];
+
+        return shortLE(i0, i1);
+    }
+
+    public int getIntLE(int pos) {
+        int i0 = array[offset + pos + 0];
+        int i1 = array[offset + pos + 1];
+        int i2 = array[offset + pos + 2];
+        int i3 = array[offset + pos + 3];
+
+        return intLE(i0, i1, i2, i3);
+    }
+}
diff --git a/filesystem/iso9660/DirectoryRecord.java b/filesystem/iso9660/DirectoryRecord.java
new file mode 100644
index 0000000..6e8409f
--- /dev/null
+++ b/filesystem/iso9660/DirectoryRecord.java
@@ -0,0 +1,50 @@
+package filesystem.iso9660;
+
+public class DirectoryRecord extends ByteParser {
+  public static final int LENGTH_OF_DIRECTORY_RECORD_START = 0;
+  public static final int LENGTH_OF_DIRECTORY_RECORD_END = 0;
+  public static final int EXTENDED_ATTRIBUTE_RECORD_LENGTH_START = 1;
+  public static final int EXTENDED_ATTRIBUTE_RECORD_LENGTH_END = 1;
+  public static final int LOCATION_OF_EXTENT_START = 2;
+  public static final int LOCATION_OF_EXTENT_END = 9;
+  public static final int DATA_LENGTH_START = 10;
+  public static final int DATA_LENGTH_END = 17;
+  public static final int RECORDING_DATE_AND_TIME_START = 18;
+  public static final int RECORDING_DATE_AND_TIME_END = 24;
+  public static final int FILE_FLAGS_START = 25;
+  public static final int FILE_FLAGS_END = 25;
+  public static final int FILE_UNIT_SIZE_START = 26;
+  public static final int FILE_UNIT_SIZE_END = 26;
+  public static final int INTERLEAVE_GAP_SIZE_START = 27;
+  public static final int INTERLEAVE_GAP_SIZE_END = 27;
+  public static final int VOLUME_SEQUENCE_NUMBER_START = 28;
+  public static final int VOLUME_SEQUENCE_NUMBER_END = 31;
+  public static final int LENGTH_OF_FILE_IDENTIFIER_START = 32;
+  public static final int LENGTH_OF_FILE_IDENTIFIER_END = 32;
+  public static final int FILE_IDENTIFIER_START = 33;
+  public static final int FILE_IDENTIFIER_END = 32;
+  public static final int lengthOfDirectoryRecord() {
+    return getByte(LENGTH_OF_DIRECTORY_RECORD_START);
+  }
+  public static final int extendedAttributeRecordLength() {
+    return getByte(EXTENDED_ATTRIBUTE_RECORD_LENGTH_START);
+  }
+  public static final int locationOfExtent() {
+    return getIntBE(LOCATION_OF_EXTENT_START);
+  }
+  public static final int dataLength() {
+    return getIntBE(DATA_LENGTH_START);
+  }
+  public static final int fileUnitSize() {
+    return getByte(FILE_UNIT_SIZE_START);
+  }
+  public static final int interleaveGapSize() {
+    return getByte(INTERLEAVE_GAP_SIZE_START);
+  }
+  public static final int volumeSequenceNumber() {
+    return getShortBE(VOLUME_SEQUENCE_NUMBER_START);
+  }
+  public static final int lengthOfFileIdentifier() {
+    return getByte(LENGTH_OF_FILE_IDENTIFIER_START);
+  }
+}
diff --git a/filesystem/iso9660/PrimaryVolumeDescriptor.java b/filesystem/iso9660/PrimaryVolumeDescriptor.java
new file mode 100644
index 0000000..72768e3
--- /dev/null
+++ b/filesystem/iso9660/PrimaryVolumeDescriptor.java
@@ -0,0 +1,96 @@
+package filesystem.iso9660;
+
+public class PrimaryVolumeDescriptor extends ByteParser {
+  public static final int VOLUME_DESCRIPTOR_TYPE_START = 0;
+  public static final int VOLUME_DESCRIPTOR_TYPE_END = 0;
+  public static final int STANDARD_IDENTIFIER_START = 1;
+  public static final int STANDARD_IDENTIFIER_END = 5;
+  public static final int VOLUME_DESCRIPTOR_VERSION_START = 6;
+  public static final int VOLUME_DESCRIPTOR_VERSION_END = 6;
+  public static final int SYSTEM_IDENTIFIER_START = 8;
+  public static final int SYSTEM_IDENTIFIER_END = 39;
+  public static final int VOLUME_IDENTIFIER_START = 40;
+  public static final int VOLUME_IDENTIFIER_END = 71;
+  public static final int VOLUME_SPACE_SIZE_START = 80;
+  public static final int VOLUME_SPACE_SIZE_END = 87;
+  public static final int VOLUME_SET_SIZE_START = 120;
+  public static final int VOLUME_SET_SIZE_END = 123;
+  public static final int VOLUME_SEQUENCE_NUMBER_START = 124;
+  public static final int VOLUME_SEQUENCE_NUMBER_END = 127;
+  public static final int LOGICAL_BLOCK_SIZE_START = 128;
+  public static final int LOGICAL_BLOCK_SIZE_END = 131;
+  public static final int PATH_TABLE_SIZE_START = 132;
+  public static final int PATH_TABLE_SIZE_END = 139;
+  public static final int LOCATION_OF_OCCURRENCE_OF_TYPE_L_PATH_TABLE_START = 140;
+  public static final int LOCATION_OF_OCCURRENCE_OF_TYPE_L_PATH_TABLE_END = 143;
+  public static final int LOCATION_OF_OPTIONAL_OCCURENCE_OF_TYPE_L_PATH_TABLE_START = 144;
+  public static final int LOCATION_OF_OPTIONAL_OCCURENCE_OF_TYPE_L_PATH_TABLE_END = 147;
+  public static final int LOCATION_OF_OCCURENCE_OF_TYPE_M_PATH_TABLE_START = 148;
+  public static final int LOCATION_OF_OCCURENCE_OF_TYPE_M_PATH_TABLE_END = 151;
+  public static final int LOCATION_OF_OPTIONAL_OCCURENCE_OF_TYPE_M_PATH_TABLE_START = 152;
+  public static final int LOCATION_OF_OPTIONAL_OCCURENCE_OF_TYPE_M_PATH_TABLE_END = 155;
+  public static final int DIRECTORY_RECORD_FOR_ROOT_DIRECTORY_START = 156;
+  public static final int DIRECTORY_RECORD_FOR_ROOT_DIRECTORY_END = 189;
+  public static final int VOLUME_SET_IDENTIFIER_START = 190;
+  public static final int VOLUME_SET_IDENTIFIER_END = 317;
+  public static final int PUBLISHER_IDENTIFIER_START = 318;
+  public static final int PUBLISHER_IDENTIFIER_END = 445;
+  public static final int DATA_PREPARER_IDENTIFIER_START = 446;
+  public static final int DATA_PREPARER_IDENTIFIER_END = 573;
+  public static final int APPLICATION_IDENTIFIER_START = 574;
+  public static final int APPLICATION_IDENTIFIER_END = 701;
+  public static final int COPYRIGHT_FILE_IDENTIFIER_START = 702;
+  public static final int COPYRIGHT_FILE_IDENTIFIER_END = 738;
+  public static final int ABSTRACT_FILE_IDENTIFIER_START = 739;
+  public static final int ABSTRACT_FILE_IDENTIFIER_END = 775;
+  public static final int BIBLIOGRAPHIC_FILE_IDENTIFIER_START = 776;
+  public static final int BIBLIOGRAPHIC_FILE_IDENTIFIER_END = 812;
+  public static final int VOLUME_CREATION_DATE_AND_TIME_START = 813;
+  public static final int VOLUME_CREATION_DATE_AND_TIME_END = 829;
+  public static final int VOLUME_MODIFICATION_DATE_AND_TIME_START = 830;
+  public static final int VOLUME_MODIFICATION_DATE_AND_TIME_END = 846;
+  public static final int VOLUME_EXPIRATION_DATE_AND_TIME_START = 847;
+  public static final int VOLUME_EXPIRATION_DATE_AND_TIME_END = 863;
+  public static final int VOLUME_EFFECTIVE_DATE_AND_TIME_START = 864;
+  public static final int VOLUME_EFFECTIVE_DATE_AND_TIME_END = 880;
+  public static final int FILE_STRUCTURE_VERSION_START = 881;
+  public static final int FILE_STRUCTURE_VERSION_END = 881;
+  public static final int APPLICATION_USE_START = 883;
+  public static final int APPLICATION_USE_END = 1394;
+  PrimaryVolumeDescriptor(byte[] array, int offset) {
+    super(array, offset);
+  }
+  public int volumeDescriptorType() {
+    return getByte(VOLUME_DESCRIPTOR_TYPE_START);
+  }
+  public int volumeDescriptorVersion() {
+    return getByte(VOLUME_DESCRIPTOR_VERSION_START);
+  }
+  public int volumeSpaceSize() {
+    return getIntLE(VOLUME_SPACE_SIZE_START);
+  }
+  public int volumeSetSize() {
+    return getShortLE(VOLUME_SET_SIZE_START);
+  }
+  public int volumeSequenceNumber() {
+    return getShortLE(VOLUME_SEQUENCE_NUMBER_START);
+  }
+  public int logicalBlockSize() {
+    return getShortLE(LOGICAL_BLOCK_SIZE_START);
+  }
+  public int pathTableSize() {
+    return getIntLE(PATH_TABLE_SIZE_START);
+  }
+  public int locationOfOccurrenceOfTypeLPathTable() {
+    return getShortLE(LOCATION_OF_OCCURRENCE_OF_TYPE_L_PATH_TABLE_START);
+  }
+  public int locationOfOptionalOccurenceOfTypeLPathTable() {
+    return getShortLE(LOCATION_OF_OPTIONAL_OCCURENCE_OF_TYPE_L_PATH_TABLE_START);
+  }
+  public int locationOfOccurenceOfTypeMPathTable() {
+    return getShortLE(LOCATION_OF_OCCURENCE_OF_TYPE_M_PATH_TABLE_START);
+  }
+  public int locationOfOptionalOccurenceOfTypeMPathTable() {
+    return getShortLE(LOCATION_OF_OPTIONAL_OCCURENCE_OF_TYPE_M_PATH_TABLE_START);
+  }
+}
diff --git a/java/nio/ByteBuffer.java b/java/nio/ByteBuffer.java
index 5160472..2f02349 100644
--- a/java/nio/ByteBuffer.java
+++ b/java/nio/ByteBuffer.java
@@ -31,6 +31,11 @@ public class ByteBuffer extends Buffer {
         return this;
     }
 
+    public ByteBuffer offset(int off) {
+        offset = off;
+        return this;
+    }
+
     private static int intBE(int i0, int i1, int i2, int i3) {
         return ((i0 << 24)
               | (i1 << 16)
@@ -55,20 +60,24 @@ public class ByteBuffer extends Buffer {
               | (i1 << 8));
     }
 
+    private int ix(int pos) {
+        return offset + pos;
+    }
+
     public byte get() {
-        byte i0 = array[position];
+        byte i0 = array[ix(position)];
         position += 1;
         return i0;
     }
 
     public byte get(int pos) {
-        byte i0 = array[pos];
+        byte i0 = array[ix(pos)];
         return i0;
     }
 
     public short getShort() {
-        int i0 = array[position + 0];
-        int i1 = array[position + 1];
+        int i0 = array[ix(position) + 0];
+        int i1 = array[ix(position) + 1];
 
         position += 2;
 
@@ -80,8 +89,8 @@ public class ByteBuffer extends Buffer {
     }
 
     public short getShort(int pos) {
-        int i0 = array[pos + 0];
-        int i1 = array[pos + 1];
+        int i0 = array[ix(pos) + 0];
+        int i1 = array[ix(pos) + 1];
 
         if (bigEndian) {
             return (short)shortBE(i0, i1);
@@ -91,10 +100,10 @@ public class ByteBuffer extends Buffer {
     }
 
     public int getInt() {
-        int i0 = array[position + 0];
-        int i1 = array[position + 1];
-        int i2 = array[position + 2];
-        int i3 = array[position + 3];
+        int i0 = array[ix(position) + 0];
+        int i1 = array[ix(position) + 1];
+        int i2 = array[ix(position) + 2];
+        int i3 = array[ix(position) + 3];
 
         position += 4;
 
@@ -106,10 +115,10 @@ public class ByteBuffer extends Buffer {
     }
 
     public int getInt(int pos) {
-        int i0 = array[pos + 0];
-        int i1 = array[pos + 1];
-        int i2 = array[pos + 2];
-        int i3 = array[pos + 3];
+        int i0 = array[ix(pos) + 0];
+        int i1 = array[ix(pos) + 1];
+        int i2 = array[ix(pos) + 2];
+        int i3 = array[ix(pos) + 3];
 
         if (bigEndian) {
             return intBE(i0, i1, i2, i3);
diff --git a/p/ISOParser.java b/p/ISOParser.java
new file mode 100644
index 0000000..5a1a046
--- /dev/null
+++ b/p/ISOParser.java
@@ -0,0 +1,19 @@
+package p;
+
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.io.IOException;
+
+import filesystem.iso9660.PrimaryVolumeDescriptor;
+
+class ISOParser {
+    public static void main(String[] args) throws IOException {
+        byte[] buf = Files.readAllBytes(Paths.get("test.iso"));
+
+        for (int i = PrimaryVolumeDescriptor.STANDARD_IDENTIFIER_START; i <= PrimaryVolumeDescriptor.STANDARD_IDENTIFIER_END; i++) {
+            System.out.print(buf[i]);
+        }
+        System.out.println();
+
+    }
+}