Question : PHP writing to a static pdf  file on web server

I am developing a website that should have a downloadable PDF file on the server. On this file there should be a serial numbering that should change when ever the file is downloaded.

My approach to this is to create a table in the MySql DB with one field called serialNo the value of which increases by one each time you click on the download link. but the logic to write to the pdf is my problem.

Any help will be appreciated.

Answer : PHP writing to a static pdf  file on web server

Fair enough, they must have their reasons, so it worked prior to Windows Vista and Windows 7 obviously?
It should work now as well maybe the problem lies in the windows sitting still for so long other things start to turn off or screensaver start up.

 I'd look into a different tool, something that can be schedualed /  programmed to play an mp3 every 2 hours like an  mp3 alarm clock.
And here comes windows media player idea I was speaking of
How to Set Windows Media Player to Start Playing Music Automatically at a Certain Time? – Use as Morning Alarm Clock
http://www.lytebyte.com/2009/07/07/how-to-set-windows-media-player-to-start-playing-music-automatically-at-a-certain-time/
alarm clocks mp3
http://www.ornj.net/citrus/
http://answers.google.com/answers/threadview/id/354299.html
http://wisecoder.com/
Hope it assists a little
Merete