Apple and Samsung are going toe-to-toe in a patents dispute mirroring a struggle for industry supremacy between two rivals that control more than half of worldwide smartphone sales.
The US company accuses Samsung of copying the design and some features of its iPad and iPhone, and is asking for billions of dollars in damages and a sales ban.
The Korean firm, which is trying to expand in the US market, says Apple infringed some of its key wireless technology patents.
Cue, who rose to prominence overseeing the iTunes and Apps stores, became the company's senior vice president of internet software and services in September. His email was introduced by Samsung during a cross-examination of Forstall on Friday.
In the email dated January 24, 2011, Cue said he had broached the idea of a smaller tablet to Jobs several times since Thanksgiving, and the co-founder was receptive "the last time."
That appeared to run counter to Jobs' famous dislike of smaller tablets. In 2010, Jobs told analysts on a conference call that 7-inch tablets should come with sandpaper, so users could file their fingers down to a quarter of their size.
"There are clear limits of how close you can physically place elements on a touch screen before users cannot reliably tap, flick, or pinch them," Jobs, who died in October after a years-long battle with cancer, said at the time.
"This is one of the key reasons we think the 10-inch screen size is the minimum size required to create great tablet Apps."
Apple still dominates the global tablet market, but rivals are closing in. Google unveiled the Nexus 7 in July to strong reviews. And Amazon's Kindle Fire tablet, with a price tag about half the iPad's, has encroached on Apple's market share. Analysts say smaller, cheaper tablets entice cost-conscious buyers unwilling to spend $500 or more for an iPad.
Court action
The trial began this week and has already granted Silicon Valley an unprecedented peek behind the curtain of Apple's famously secretive design and marketing machine.
Forstall described the early days of the iPhone's top-secret inception. The smartphone that went on to revolutionize the mobile industry was developed in a building engineers nicknamed the "purple dorm." Security was so tight employees sometimes had to swipe their badges four times just to get in, he said.
