An access log is a text file which contains a full list of all the files accessed by your website visitors. All the files which were requested in one way or another will be included, so when you have a PHP script program and a website visitor opens just the home page, for example, you may find plenty of files in the log. It is because there are components on the home page which are embedded - parts of other web pages, pictures, etc. All of these files shall be listed inside the access log, so that you can get a full picture of the way your website functions. The data is in plain text format, so the logs are occasionally referred to as "raw data" as well. An access log shows the name of every requested file, the path to it, the date it was accessed, in addition to the user’s IP address, browser and Operating System. More information, like the referrer site, is sometimes supplied too. A log file may be processed by various desktop apps for statistical purposes as an addition to the web stats supplied by your web server.