In a Monday filing in the U.S. district court for the Northern District of California in San Jose, Magistrate Judge Howard R. Lloyd ordered Jobs could answer questions for two hours about RealNetworks Inc.'s Harmony technology. This technology was rolled out in 2004 and briefly allowed songs sold by RealNetworks' online music store to be played on iPods, despite Apple's use at the time of encryption technology to prevent this. Apple issued an iPod and iTunes software update shortly thereafter that disabled this interoperability.
The court found that "Jobs has unique, non-repetitive, firsthand knowledge" about the issue, the judge said.
The order stems from a 2005 class action suit led filed against Apple, led by Thomas Slattery, alleging Apple's use of FairPlay encryption technology gave it a monopoly on the digital player and audio download markets.
Before 2009, Apple used FairPlay on songs bought from its iTunes music store to stop users from making unauthorized copies of tracks. FairPlay limited the playing of these songs to iPods, which meant users with other types of digital music players could not play them, and made it so that other digital music purchases with their own copy-preventing encryption couldn't be played on an iPod. Users have always been able to copy their own songs from CDs into iTunes and move that music onto their iPods.
Apple spokeswoman Kristin Huguet said the company would not comment on ongoing litigation.
Jobs, 56, has been on medical leave since January, when he announced that he would take his third leave of absence in seven years to focus on his health. During those years, he has survived a rare but curable form of pancreatic cancer and undergone a liver transplant.
Jobs emerged from his leave on March 2 to unveil the company's latest tablet computer, the iPad 2.
[Editor's note: The original version of this article misstated its author. The story came from The Associated Press.]