With an operating system chosen, we can move on to learning about and configuring the first two layers of the stack, Zope itself and the ZEO database server.
A typical desktop installation of Plone involves a single Zope process, which reads from and writes to a
Data.fs file directly. ZEO, Zope's specialized database server, takes over that responsibility, and one or more copies of Zope (called Zope instances) communicate with it via a socket. This setup has several advantages: