static page caching for Action Pack (removed from core in Rails 4.0)

 Page caching is an approach to caching where the entire action output of is
 stored as a HTML file that the web server can serve without going through
 Action Pack.
 .
 This is the fastest way to cache your content as opposed to going dynamically
 through the process of generating the content. Unfortunately, this incredible
 speed-up is only available to stateless pages where all visitors are treated
 the same. Content management systems -- including weblogs and wikis -- have
 many pages that are a great fit for this approach, but account-based systems
 where people log in and manipulate their own data are often less likely
 candidates.