Let me confess: I would have guessed that Google was already a member of the Open Compute Project.

But no, it's taken five years for the search giant to join up with the open source hardware community that Facebook founded.

Google's participation, announced today at the OCP Summit in San Jose, Calif., comes because the company wants to open source one of its hardware designs: a data center rack that runs on 48 volt power.

It might sound esoteric (as if the other stuff we cover isn't), but think of the data center rack as Google's skeleton — in the sense that, without a skeleton, your body turns into a floppy bag of liquid. Google needs these things to be uniform, power-efficient, and procurable in mass quantities.

That's all true of ordinary equipment racks, but they were running up against limits of power delivery and efficiency.

Google decided the answer was to move racks off of their 12V standard. "It became clear that 48V is the right answer," said Urs Hölzle, Google's senior vice president of technical infrastructure, at this morning's keynote.

Google first tried leaving servers at 12V while bringing 48V into the rack, but now it's decided to go all-in with 48V, all the way down to the server motherboard.

Having now designed that rack, Google would appreciate not being the only entity in the world that wants to build it. So, it's joined OCP and is submitting the design for open source consideration.

This won't be the end of Google's OCP participation either. Hölzle sees possibilities in storage management, where a cloud mentality means operators care less about individual disk drives and more about the collective system that those drives represent.

Management software in general could use a push, too, he said. "OCP is still light on software, and there's a lot more that could be standardized."