Usefull reference:
Value Permission Level
400 Owner Read
200 Owner Write
100 Owner Execute
40 Group Read
20 Group Write
10 Group Execute
4 Global Read
2 Global Write
1 Global Execute
(taken from http://www.onlamp.com/pub/a/php/2003/02/06/php_foundations.html)