I apologize that this is a very fundamental question.  How does apache httpd on XP open the files it serves?

If there is very frequent access to an html file and the administrator plans to replace it frequently using an application, what is the best way to replace it so that the admin's app never gets locked out and the client app never gets a corrupted file?  I know this is a good fit for dynamic content, but I was hoping to put off that development for now.

Along the same lines, if the admin's app tries to delete a file while it is being served, there is a small window of time where the file is open and can't be deleted, right?