Home Is Home: The Physical Practicalities - Smart Home Automation with Linux and Raspberry Pi - page 121

CHAPTER 4
Home Is Home: The Physical
Practicalities
Running your own home is a great feeling. Having it run from your own Linux server is even better. Just being able
to tell people that your home page is quite literally your home page lifts your geek credentials one notch higher. But
having a machine running 24/7 introduces a permanent noise from the fans and hard drives, blinking lights, and extra
heat. Being able to control one machine from another requires cabling. In this chapter, I'll cover some of the basics
about the physical practicalities of a home automation setup.
Node0
Node0 is the place in the house where all the cables end up, or are “home run.” This means Cat5 Ethernet, AV cables,
IR relays, and even X10 wireless transceivers might all live within a single location. It is also the entry point for the
outside world, so modems and routers will also live here.
Function and Purpose
The idea of using a single Node0 is to keep everything out of the way of day-to-day living. This means that the server,
no matter how big and noisy it might be, can be positioned where it least impacts those trying to sleep or study. It also
allows the mass of cables and expensive hardware to be placed somewhere, perhaps locked up with a single key, to
minimize careless accidents involving spilled drinks and young children.
Although this introduces a single point of failure (a big no-no in general systems administration), the risks
involved at home are much fewer, and it doesn't impact the already present single point of failure, namely, the sole
modem cable entering and leaving the house.
The server machine itself also exists to provide a central repository of all the house-related data and information,
including the main web site and e-mail services, and an abstraction to the various media repositories that might
exist on other machines. In this way, every nontechnical house dweller can connect to //server/media and be
transparently connected to whatever hard disk (on whatever machine) happens to include it. This makes it possible to
upgrade and move disks around as they become full, without fielding support calls from your family!
Having a primary server generally requires it to remain switched on 24/7. Centralizing the tasks to a single
location and unifying all the services onto a single machine means that only the Node0 machine requires protection
from power outages (via a UPS) or theft (via a strong lock). Indeed, the data most at risk is usually on stand-alone
laptops, so I'll cover backup plans for them later, too.