final ScsiOperationCode opCode = ScsiOperationCode.valueOf(parser.getCDB().get(0));
ReadCapacityCdb cdb;
if (opCode == ScsiOperationCode.READ_CAPACITY_10)
cdb = new ReadCapacity10Cdb(parser.getCDB());
else if (opCode == ScsiOperationCode.READ_CAPACITY_16)
cdb = new ReadCapacity16Cdb(parser.getCDB());
else {
// programmer error, we should not be here, close the connection
throw new InternetSCSIException("wrong SCSI Operation Code " + opCode + " in ReadCapacityStage");
}