PHP4 vs PHP3

hi, folks! Can anybody explain to me how is possible concurrent running of both PHP4 and PHP3 as Apache's module (as described in INSTALL file)? I can't imagine how the PHP engine solves, which codebase is old, whih is new. Well, second question follows: where is the place I could know about REAL differences between php3 and Zend? I have the following code: class tableCalendar { var $defaultPath = $GLOBALS["PathData"]; ... PHP4 reports about "parse error". If I comment out $GLOBALS and assign "PathData" later, then it complains: "Parse error: parse error, expecting T_OLD_FUNCTION' or T_FUNCTION' or T_VAR' or '}'' in /usr/local/apache/lib/.date_time.lib on line 146" It sounds perfectly weird to me.:( -- WBR, Yury Bokhoncovich, SysAdmin at FIS.