Infrastructures for information technology systems

The existing definitions for infrastructure notion do not seem to completely capture its impact, outreach, and the importance of entities it represents. Thorough understanding of the concept is necessary if we are to develop long-lasting adaptive infrastructures, which can handle the continuously increasing service demands and threats. We study the infrastructure notion to understand and clarify its definition, impact, and scope. We take different perspectives for exploring subtle relationships between a system and its infrastructure. We provide various classifications to cope with the inherent complexity of the infrastructure notion. Our emphasis is the information technology infrastructure, its security, and survivability.