5-1 What is IT infrastructure, and what are the stages and drivers of IT infrastructure evolution? Define IT infrastructure from both a technol- ogy and a services perspective. List each of the eras in IT infrastructure evolution and describe its distinguishing characteristics. Define and describe the following: web server, application server, multitiered client/ server architecture. Describe Moore's Law and the Law of Mass Digital Storage. Describe how network economics, declining communications costs, and technology stan- dards affect IT infrastructure.