private void getdatabeginptr()
	{
		try { fdbf.seek(0); } catch (IOException e) {}
		try { signature = (byte) fdbf.readUnsignedByte(); } catch (IOException e) { e.printStackTrace(); }
		fpt_file = false;	//( signature == (DOS_FOX ? SIG_DOSFOX_WITH_MEMO : SIG_WINFOX_WITH_MEMO) );
		
		try { fdbf.seek(8); } catch (IOException e) {}
		data_begin_at = readNumber(0,2);
		record_size = readNumber(0,2);
		
		try { fdbf.seek(28); } catch (IOException e) {}
		cdx_file = ( readChars(0,1).charAt(0) > 0 );		
	}