On 1/15/08, Tim Gales <[EMAIL PROTECTED]> wrote: > Michael B Allen wrote: > [...] > > PHP is not Mathematica. It's primarily a template based system for > > emitting text... > > Peter Yared (who gave a presentation back in '05) says many application > servers are basically 'text pumps' > http://peteryared.blogspot.com/2003/09/application-servers-2004-big-muffin-in.html
There's one major issue with "The Donut Architecture" being web services which is that without a single lock to coordinate the efforts of everyone you have a race-condition nightmare. It's very important to realize that each service must check a state variable with a single authority. A database is ideal for that because it implicitly provides a lock. Meaning, if you have web servers A, B and C and A does some work and indicates to B that it can do some work and then B sends C some work ... etc then it becomes very difficult to stop or move things in the workflow. The key is to use a state variable in the database and always check it before performing the next job. Unfortunately most people do not realize this and end up with systems that are very difficult to control. Application server technology is one big game of Whac-A-Mole. Mike -- Michael B Allen PHP Active Directory SPNEGO SSO http://www.ioplex.com/ _______________________________________________ New York PHP Community Talk Mailing List http://lists.nyphp.org/mailman/listinfo/talk NYPHPCon 2006 Presentations Online http://www.nyphpcon.com Show Your Participation in New York PHP http://www.nyphp.org/show_participation.php
