an operating system for web applications

In developing web applications, I often notice the parallels between "web" design patterns and OS design patterns. For example, there are clear analogies between memcached and memory, and the DB and disk. It's the memory hierarchy all over again, and the same algorithms exist (LRU, etc). Would it be possible to create an OS layer to abstract out the DB and the distributed cache, to make writing web apps simpler? I'm curious what the major challenges would be.