|What a sad response. |
VMS is an older operating system used by large companies who want great reliability and need to run programs which were developed a number of years ago and are considered too costly to replace.
It is usually used for large database systems or complex applications which took yeatrs to deveop, and in some cases the original source code is not available.
the main claim to fame of vms was clustering, which is using multiple systems to run parts of the program simultaneously, or to provide redundant hardware. Many concepts from VMS have been included in more recent systems.
For more information, go to http://en.wikipedia.org/wiki/OpenVMS