i'm new to php but i'm a bit familiar with servlet etc.
I have 2 questions:

- when a php site s browsed by many users at the same time, does the server
completey execute one request after another or are they somehow executed

- when a user uploads a file, is this file upload already a php-thread so
would this block all the other users? or is this independent from oho, the
server receives the file and then triggers PHP to execute?

Some hints about this qould be appreciated.