Livermore and Catz were the top-level executives in charge of HP and Oracle's cooperation in developing and selling enterprise hardware and software, said Livermore, who ran HP's enterprise business from 2004 until 2011. She testified in a , over HP's Itanium server platform, as Catz looked on. Livermore is scheduled to continue her testimony on Tuesday.

Livermore and Catz might have talked on the phone once per quarter or several times in one week, depending on what the two companies were working on, Livermore said. Among other things, they would discuss what was going well or not so well at either business. "We had quite candid and open conversations," Livermore said. She is still a member of HP's board.

The companies' work together has generated billions in revenue, Livermore estimated. While HP produced millions of enterprise servers, Oracle wrote the software that ran on most of them. In particular, Livermore estimated that 84 percent of HP's Itanium-based servers run Oracle's database software. HP developed Itanium with Intel to run mission-critical applications such as databases, and that chip is still at the heart of the servers from HP's Business Critical Systems (BCS) division.

But Oracle's acquisition of server maker Sun Microsystems, announced in 2009, and its hiring of former HP CEO Mark Hurd right after he was fired from HP in September 2010, eventually spoiled the companies' relationship.

When Oracle announced it would buy out the struggling Sun, Livermore said she and HP were concerned about how it would affect the competitive environment. But it also gave Oracle a hardware portfolio under its roof. "We also weren't sure how Sun would act, moving forward, in terms of making their software available on our platforms," Livermore said.