International Data Corporation raised its 2011 forecast for global sales of tablet computers by 6.2 percent to 53.5 million units on the strength of Apple Inc.’s iPad and Google Inc.’s Android operating system.

Though sales in the first calendar quarter fell 28 percent from the prior quarter, Framingham, Massachusetts-based IDC raised its forecast for the year citing increased competition between tablets. Samsung Electronics Co. and Motorola Mobility Holdings Inc. continue to lag behind Apple because unlike the iPad maker they require customers to buy a data plan, IDC said in a statement Friday.

The share of Android-based devices grew 8.2 percentage points to account for 34 percent of the tablet market, IDC said.

“Like the PC market, media tablets had a bit of a challenging quarter in Q1, as concerns about general macroeconomic issues and the post-holiday letdown took a toll on demand,” IDC vice president Bob O’Donnell said in a release. “We expect the rest of the year to be much stronger.” 

(Bloomberg)