code: private void writeHashIndex(int index, long value, int tableid)
                      throws IOException {
  
          long diskloc = header.calcOffset(index, tableid);
          filemgr.seek(diskloc);
          filemgr.writeLong(value);
          updateHtindex(index, value, tableid);
      }
docs: ************************************************************************
  Given an index into the hash table and a value to store there, find it
  on disk and write the value.
  ***********************************************************************