Need a Tiny Caching Method

[eluser]Mareshal[/eluser]
I need a simple caching method, without using a complicated caching script or something. I need this especially for site settings, and then I might extend this if it works. I was thinking to get all data from DB, and put all them into a hidden file, with a random generated name. Then, when I update the settings, just update the database, and in the same time the file. Would this be a good idea?