This IDC study reviews the growth of the overall client and server operating environments markets during 2005 and 2006 and provides a shipment and installed base forecast through 2010. "On the client side of the market, the Windows domination stands firm, but Linux client operating environments have made measurable progress during 2005 and 2006," said Al Gillen, research vice president, System Software at IDC. "In the server operating system market, Linux continues to gain share, but Microsoft's position remains formidable there, too."