Windows Vista of January 2009, it had been announced that Vista usage had surpassed Microsoft's pre-launch two-year-out expectations of achieving 200 million users. At the release of Windows 7 (October 2009), Windows Vista (with approximately 400 million Internet users) was the second most widely used operating system on the Internet with an approximately 19% market share, the most widely used being Windows XP with an approximately 63% market share. In May 2010, Windows Vista's market share had an estimated range from 15% to 26%. On October 22, 2010, Microsoft ceased sales of retail copies of Windows Vista, and the OEM sales for
Windows Vista I/O technologies Windows Vista I/O technologies Windows Vista introduced a number of new I/O functions to the Microsoft Windows line of operating systems. They are intended to shorten the time taken to boot the system, improve the responsiveness of the system, and improve the reliability of data storage. Vista modifies the behavior of asynchronous I/O operations. With the new asynchronous I/O APIs, a thread, different from the one that issued the I/O request, can be notified when the operation completes. With this, a single thread can issue all the I/O requests, and then switch to a different worker thread. If this thread