For a long time, Samsung’s been trying to take down the iPad. Since 2010, the company has released a seemingly endless line of tablets aimed at taking away market share from Apple. But the effort has paid off to some degree — Samsung reported shipping 40 million tablets last year, far more than it had in prior years. Now Samsung’s announcing its newest tablet line, the Galaxy Tab S, available in 8.4-inch and 10.5-inch sizes.