Why this difference? php_self and script_name

I have compared php 4.0 installed on both win98
and on linux (as apache module, - built, not rpm)

Simple script: "alpha.php" reads:
<?
echo "PHP_SELF: $PHP_SELF<br>";
echo "SCRIPT_NAME: $SCRIPT_NAME <br>";
?>

1. Linux:
Apache DocumentRoot is "/home/httpd/html"
Script is /home/httpd/html/alpha.php
Access from browser: http://localhost/alpha.php,
Result:
  PHP_SELF: /alpha.php
  SCRIPT_NAME: /alpha.php

2. Windows:
Apache DocumentRoot is "c:/home/httpd/html"
Script is c:/home/httpd/html/alpha.php
php.exe is in c:/php

Access browser: http://localhost/alpha.php,
Result:
  PHP_SELF: /php/php.exe/alpha.php
  SCRIPT_NAME: /php/php.exe

Is the windows version reporting the correct information
or is this a bug?