What's wrong with an ad rotation script like this?

<?php

  function load_setting() {
    return (int) trim( file_get_contents( 'setting.pedro' ) );
  }

  function load_counter() {
    return (int) trim( file_get_contents( 'counter.pedro' ) );
  }

  function load_adcode($which) {
    return trim( file_get_contents( "ad{$which}.pedro" ) );
  }

  function save_counter($count) {
    file_put_contents('counter.pedro',$count);
  }

  $counter = 1 + load_counter();
  if($counter >= load_setting())
    $counter = 0;
  save_counter($counter);
  echo load_adcode($counter);

?>

Code (markup):

Is it smart to save data to files like this? And any other suggestions?

 

Why do you need to load the counters ? Would be better for performance If you dont load the counters every time.

You could make a cron job every hour to count the stats, not every time someone load the page.

You have one log file that saves what ad is published and you make a summary every hour.