Microsoft Corp. , the world’s largest software maker, won’t release a competitor to Apple Inc. and Google Inc. ’s tablet operating systems until the 2012 back-to- school season, people with knowledge of the plans said.

Microsoft Corp. , the world’s largest software maker, won’t release a competitor to Apple Inc. and Google Inc. ’s tablet operating systems until the 2012 back-to- school season, people with knowledge of the plans said.