- Spacetime (Wikipedia)
In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why different observers perceive differently where and when events occur.
- Windows 2000 (Wikipedia)
Windows 2000 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It is the direct successor to Windows NT 4.0, and was released to manufacturing on December 15, 1999, officially released to retail on February 17, 2000 for all versions, and on September 26, 2000 for Windows 2000 Datacenter Server. It was Microsoft’s primary business-oriented operating system until the introduction of Windows XP Professional in 2001.