I should point out that not all the machines that were connected up were on at once (or you'd have seen the glow from space) - no, one or other was turned on from time to time to do things like run Windows + Internet Explorer in order to check whether a website design worked cross-platform or not.

It just became simpler to rescue a box from Freecycle and add it to the network, than to muck about with things like dual/triple/multi-booting a single box.

Nonetheless, some things ended up being on all the time anyway - notably a media server and a mail/dns server.

Then - comparatively recently - along came a massive improvement in hardware virtualisation technology, which allows you to run many independent virtual machines ("VMs") on one physical piece of sufficiently capable hardware.

I picked VMWare as my virtualisation platform, there are others but this was simple to experiment with and has the huge benefit (to me) of doing what it said on the tin right out of the, er, box :-). Xen may be wonderful, but trying to get my head round it quickly wasn't.

Anyway, the upshot of the experiments was that I've managed to replace my physical DNS and mailserver, the media server, two Windows boxes (2000 + IE6 and XPHome + IE7) and a development webserver with VMs running on a £400 laptop from those nice people at the Linux Emporium and an IcyBox RAID network attached storage appliance.

The house's daytime base load is down by around 200W to a much more acceptable 350W - which is a 40% saving.

Plus I'll finally be able to get some space back!
--
Simon