User level techniques for improvement of disk I/O in WWW caching

Traditionally, Wide-Wide-Web caching systems store WWW contents in filesystem. However, general purpose filesystems have a lot of unnecessary features for caching systems accompanied with data I/O. For example, typical filesystems maintain directories, inodes and free block maps (they are know as metadata). Those operations cause notable overhead. Modem WWW caching systems employ specialized filesystems for WWW caching. Furthermore, such implementations are often optimized to particular OSs and/or hardwares. Although this approach reduces overheads of filesystem, it is not portable and is expensive. This article describes an alternative approach, user level techniques for improvement of disk I/O.