Description:
------------
rand is not random !!!. Random number repeat every 32768 time     
  :-(((

 _ 0 _ 	 _ 8512030 _ 
 _ 1 _ 	 _ 5655227 _ 
 _ 2 _ 	 _ 6934082 _ 
 _ 3 _ 	 _ 2293270 _ 

.......
 _ 32768 _    _ 8512030 _ 
 _ 32769 _    _ 5655227 _ 
 _ 32770 _    _ 6934082 _ 
 _ 32771 _    _ 2293270 _ 
......

Reproduce code:
---------------
echo '<pre>';

for ($i=0; $i<160000; $i++) {
$ch01=rand(900000, 9999999);
echo " _ $i _ \t _ $ch01 _ \n"; }

Expected result:
----------------
..... 
  realy  random number !

Actual result:
--------------
 _ 0 _ 	 _ 8512030 _ 
 _ 1 _ 	 _ 5655227 _ 
 _ 2 _ 	 _ 6934082 _ 
 _ 3 _ 	 _ 2293270 _ 

.......
 _ 32768 _    _ 8512030 _ 
 _ 32769 _    _ 5655227 _ 
 _ 32770 _    _ 6934082 _ 
 _ 32771 _    _ 2293270 _ 
......