New Delhi, Oct 30 (PTI) To tap the fast growing web and personal computers market, internet giant Google is working on an operating system, a move that is likely to pose a stiff challenge to Microsoft's dominance.

"We are working on an operating system... we feel, when other operating systems became part of the Web, the world was not connected the way it is today," Google Global Sales Operations and Business Development President Nikesh Arora said.

"Whether our operating system replaces the existing ones, I don't know. Customers will choose that," he said, while speaking at the HT Leadership Summit here.

In July, Google announced plans to launch its own operating system for personal computers. The planned open source 'Google Chrome Operating System' is expected to be available in the second half of 2010.

Microsoft has about 90 per cent share in the global market for operating systems.