private void writeNumber ( int side, int ln, long numb, boolean FF )
	{
		long r = numb;
		byte[] g = new byte[ln];
		for(int i=0, l=ln;l>0;l--)
			{
			if(side>0) r=(l==1? numb : numb>>((l-1)<<3) );
			int b = (int)((FF && numb==-1) ? 0xff : (r & 0xff));
			g[i++]=(byte)b;
			if(side==0) r>>=8;
			}
		try { fidx.write(g); }
		catch (IOException e) { e.printStackTrace(); }		
	}