NeoSmart Technologies’ File-Based object caching extension for WordPress re-implements the cache-to-disk object caching feature of WordPress 2.0 through to 2.2. NeoSmart Technologies is also committed to the maintenance and support of the file-based caching mechanism.
Please be careful with the use of this plugin. It’s been disabled in the default WordPress codebase since WordPress 2.1 as a result of certain shared webhosts complaining of increased disk I/O access and thrashing when WordPress is subjected to extreme load times (as in the event of a Digg or Slashdot attack); so make sure your disk is fast enough to make it worth using this extension.
NeoSmart Technologies advises the use of one of the memory-based caching extensions (below) for all WordPress users on dedicated servers.
Download: File-Based Object Cache Extension
Full List of WordPress Object-Caching Extensions