Another corner of Sony, the PlayStation Network that connects gamers to both the Sony online store and multiplayer game play on Sony devices, was attacked and out of commission temporarily Sunday. People who attempted to log in to the store were shown a sign saying the outage was “the Internet’s fault.” Gamers logging in during primetime on the West Coast were shown a sign saying the site was undergoing maintenance and online functions weren’t available. Sony said it found no trace of data loss and it is investigating the root cause of the outage.

Lizard Squad Twitter postAn anonymous hacker group calling itself Lizard Squad, which has been involved in previous online attacks of Sony and other companies, rather cryptically claimed responsibility for the attack on Twitter. It also posted a link to an episode of DramaAlert, a YouTube video news site focused on gamers, that mentioned the attack. Earlier in the weekend, Lizard Squad also claimed responsibility on Twitter for online attacks against Anonymous, the libertarian hacker collective loosely tied to the Occupy Wall Street movement.

Sony Pictures Entertainment was hit with a devastating hacking attack less than two weeks ago that shut its computers for several days, and led to the theft and partial public release of an estimated 100 terabytes of company records and documents (roughly 10 times the amount of documents in the Library of Congress).

Some blamed that attack on North Korean government operatives, in retribution for Sony Pictures’ upcoming movie The Interview, a comedy starring Seth Rogen and James Franco that depicts a CIA plot to assassinate North Korea’s autocratic ruler, Kim Jong-Un. Over the weekend, the North Korean government denied that it had anything to do with the attack but praised the people who carried it out.

The latest attack is of a very different sort, on a very different part of Sony, the booming game unit that just celebrated the 20th birthday of its PlayStation line of video game consoles. This was what is known as a distributed denial-of-service attack, where armies of remotely controlled computers (called “botnets”) all try to access a site simultaneously, making it impossible for anyone else to get through.

The PlayStation Network also has had its own history of hacker attacks, including one in August, but most devastatingly in April 2011, when the network and another Sony service, Qriocity, were ransacked of personal data and credit-card information for 77 million customers, one of the biggest computer attacks in history.

A possibly related and much smaller attack on Sony Online Entertainment several days later also exposed a comparatively much small number of accounts. PSN was out of commission for about two weeks. Sony was also heavily criticized for waiting a week to notify its customers of the attack and its implications.