Extreme Programming (XP) was developed by Kent Beck, Ward Cunningham, and Ron Jeffries during the 1990s as a set of dynamic programming practices. Today, XP is the most often adopted agile methodology in the high-technology industry. The most noticeable practices of XP are pair programming and test-driven development. Although XP provides planning practices for project management, it is often seen as an agile engineering process.
Ken Schwaber and Jeff Sutherland, who developed Scrum in the 1990s, define it as a framework for agile project management rather than an agile process. Scrum has its origins in lean manufacturing, iterative-incremental development, and the Smalltalk engineering tools. Scrum provides a simple set of rules. Aside from these simple rules, Scrum is extremely flexible and adaptive to emerging situations. Scrum is a term used in rugby and not an acronym. In a nutshell, Scrum is quite different from existing project management practices. First, the role of a traditional project manager is shared among three different roles: the product owner, the scrum master, and the team. Second, two different backlogs are used to manage scope: the product backlog, which captures the scope of the product, and the sprint backlog, which contains the detail work for the current iteration. A sprint, which is the Scrum synonym for an iteration, is four weeks long. The entire Scrum team meets daily for 15 minutes so that each member can give other team members a quick update. Scrum is very popular in the agile industry.