> most of the time the page cache offers the semantics you actually want, memory quick access backed up by persistent storage. If you are thinking about a ram

> most of the time the page cache offers the semantics you actually want, memory quick access backed up by persistent storage. If you are thinking about a ram disk it is likely because you want guaranteed low latency. With a cache you get hosed by delays when pages are flushed. I remember having to run daemons just to keep caches warm by periodically accessing data that I might need later without having to wait for it.