Mainframes are also hundreds of computers running scalable software. The hardware facebook uses is not commodity - it's a stripped down PC. I think google sti

Mainframes are also hundreds of computers running scalable software. The hardware facebook uses is not commodity - it's a stripped down PC. I think google still uses commodity PCs, but I suspect they alter the power system. The use of the PC is driven by the software, which originated on PCs running linux. They're not going to rewrite it all to run on a mainframe.