Typical enterprises use dozens, hundreds, and sometimes even thousands of applications, components, services, and databases. Many of them are custom built in-house or by third parties, some are bought, others are based on Open Source projects, and the origin of a few--usually the most critical ones--is completely unknown.

A lot of applications are very old, some are fairly new and seemingly no two of them were written using the same tools. They run on heterogeneous operating systems and hardware, they use databases and messaging systems from various vendors, and they were written in different programming languages.