Technology History | Computer History Museum — The Search Index Ran on Cork and Bare Motherboards

The brown sheets between the shelves are cork.

They are why this rack is known as the corkboard server: bare motherboards stacked on cheap board, with the cork insulating them so nothing shorted against the metal below.

Google assembled about thirty racks like it for its 1999 data centre, and the museum's own label is blunt about the results — many of the installed PCs never worked, and the ones that failed were difficult to repair.

That was tolerable, because it was the design. Pre-built rack-mount machines from Dell or Compaq cost far more per unit of computation, so the company bought commodity parts and wrote software that assumed the hardware underneath would fail.

The Smithsonian, which holds another rack from the same batch, records the configuration: each row carried four personal computers and eight 22-gigabyte hard drives.

Thirty racks of that held the index of the web as it then existed.

The approach outlived the cork. Fault tolerance placed in software rather than bought in hardware became the working assumption of Google's later data centres, and of most cloud infrastructure since.

Three museums display a rack from this set: this one in Mountain View, the National Museum of American History in Washington, and the Science Museum in London, whose catalogue names the builder as King Star Computers of California.

The address carries its own argument. This building was designed as the headquarters of Silicon Graphics, and the museum acquired it in 2002 as that company declined, a mile from the SGI campus Google would move into the following year.

Look closely at the boards in the photograph and you can read the hand-lettered labels, JJ9 and JJ13 and JJ17, on machines that answered live search queries.

The rack is a collection object rather than a permanent fixture of one gallery, so check what is currently on view before travelling for it.

The IEEE's Milestone plaque for PageRank is mounted on the inside face of the front patio wall near the main entrance, reachable at any hour.

Sources: Computer History Museum exhibit label and building history; National Museum of American History object record; Science Museum Group collection record. Cover photo: James Fry, CC BY-SA 3.0; second photo: Photographing Travis, CC BY 2.0, both via Wikimedia Commons.