In an early morning interview with business channel CNBC, McGraw-Hill CEO Terry McGraw appeared to reveal some details of the tablet's inner workings, the subject of much industry speculation and gossip in recent weeks.
"We have worked with Apple for quite awhile—the tablet is going to be based on the iPhone operating system," said McGraw.
McGraw said that's significant because it means the tablet will be compatible with content and apps that McGraw-Hill and other publishers have already created for the iPhone.
"We have 95 percent of all our materials that are in e-book format on that one," said McGraw.
Magazine and newspaper publishers may look to Apple's tablet as a delivery mechanism that could help them regain their competitive advantage against online blogs and news services. Its presence could also help them extract better terms from the makers of rival devices, like Amazon's Kindle.
Also speaking on CNBC, in an interview from the Davos economic summit, WPP Group head Sir Martin Sorrell appeared to have an inside track on the device's name, referring to it as the "iTablet." Whether that's the name Jobs will announce later Wednesday remains to be seen.
Apple has scheduled a press conference in San Francisco for Wednesday at the Yerba Buena Center for the Arts Theater. The conference is set to get underway at 1 pm Eastern time.
Apple shares were off .39%, to $205.14, in early trading Wednesday.