System Failure of PlayStation Network Due to a-Leap-Year-Judging?

PlayStation Network (PSN) is marred by its system failure on 1 March 2010. During this problem occurred, users of PlayStation 3 (PS3) gaming console couldn't sign up PSN and some users said that their data was broken. A newer PS3 which was called "slim model" is safe.

Sony Computer Entertainment (SCE) said that this problem occurred due to a bug of an internal clock of PS3 and it confused 2010 with a leap year. They also said that this system failure was solved already because "29 February 2010" was ended. However, they haven't announced yet about a reason of the bug and a treatment of users whose data was crashed.

I think that this bug involves something about authentication because users' broken data was bound for PSN account and a-leap-year-judging algorithm is too simple to make a mistake in ordinary circumstances. So, I wanna know why they generated this kind of bug.


SCE's announcement (in Japanese)
http://www.jp.playstation.com/info/support/sp_20100302_ps3.html