[PHP-WIN] Sessions

[Шестаков Николай]

OS: WinXP Pro SP1.
Apache 2.
php 4.3 isap

index.php

    <?php
     session_start();
     session_register("sa");
     echo $sa."<br>";
     $sa=1;
     echo $sa."<br>";
     echo session_id()."<br>";
     echo session_name()."<br>";
     echo session_module_name()."<br>";
     echo session_is_registered("sa")."<br>";
     echo session_save_path()."<br>";  
    ?>
    <a href="http://localhost/index2.php";>increment</a>

get 
 
    1
    728be1c2b387346bf08ec42680571589
    PHPSESSID
    files
    1
    C:\Program Files\php-4.3.0-Win32\sessiondata
    increment 

sess_728be1c2b387346bf08ec42680571589 is "sa|i:1;".

index2.php
    <?php
     session_start();
     session_register("sa");
     
     echo $sa."?<br>";
     $sa+=2;
     echo $sa."<br>";
     echo session_id()."<br>";
     echo session_name()."<br>";
     echo session_module_name()."<br>";
     echo session_is_registered("sa")."<br>";
     echo session_save_path()."<br>";  
    ?>
    <a href="http://localhost/index2.php";>increment</a>

get
     ?
    2
    728be1c2b387346bf08ec42680571589
    PHPSESSID
    files
    1
    C:\Program Files\php-4.3.0-Win32\sessiondata
    increment 

sess_728be1c2b387346bf08ec42680571589 is "sa|i:1;".

sessiondata access is full.

Why?