President Obama is meeting with Chinese President Xi Jinping at a summit in California today amidst a growing dispute between the two countries over cybersecurity. Washington has accused China of cyberspying, including snooping on advanced U.S. weapons designs. But the White House has said little publicly about its own hacking abilities. Bloomberg Businessweek recently disclosed how a secretive unit inside the National Security Agency, called “Tailored Access Operations,” conducts massive cyber-espionage on overseas computer networks. The Pentagon hackers harvest nearly 2.1 million gigabytes every hour. That is the equivalent of hundreds of millions of pages of text. The Pentagon recently promoted the deputy chief of the secretive NSA unit, Rear Admiral Willie Metts, to become director for intelligence of U.S. Pacific Command.