code: private void deserializeCommon(byte[] descriptor) throws IOException {
          this.systemIdentifier = Util.getAChars(descriptor, 9, 32, this.encoding);
          this.volumeIdentifier = Util.getDChars(descriptor, 41, 32, this.encoding);
          this.volumeSetIdentifier = Util.getDChars(descriptor, 191, 128, this.encoding);
          this.rootDirectoryEntry = new Iso9660FileEntry(this.isoFile, descriptor, 157);
      }
docs: Read the information common to primary and secondary volume descriptors.
  
  @param descriptor the volume descriptor bytes
  @throws IOException