Microsoft WindowsThe Microsoft Windows family of operating systems originated as a graphical layer on top ofthe older MS-DOS environment for the IBM PC. Modern versions are based on the newerWindowsNT core that first took shape in OS/2 and borrowed from OpenVMS. Windows runs on 32-bitand64-bit Intel and AMD computers, although earlier versions also ran on the DEC Alpha, MIPS,andPowerPC architectures (some work was done to port it to the SPARC architecture).As of 2004, Windows held a near-monopoly of around 90% of the worldwide desktop marketshare,although this is thought to be dwindling due to the increase of interest focused on open sourceoperating systems.  It is also used on low-end and mid-range servers, supportingapplicationssuch as web servers and database servers. In recent years, Microsoft has spent significantmarketing and R&D money to demonstrate that Windows is capable of running any enterpriseapplication (seethe TPC article).