Brownfield Systems

Brownfield systems include and interact with a number of existing systems — many requirements concern this interaction and don't really lend themselves to flexibility and incremental development; changes to existing systems often require negotiation with their managers

Explanation

Large systems are 'brownfield systems' (Hopkins and Jenkins, 2008) — they include and interact with a number of existing systems. Many of the system requirements are concerned with this interaction and don't really lend themselves to flexibility and incremental development. Political issues can also be significant — often the easiest solution is to change an existing system, but this requires negotiation with the managers of that system.