XP Vs Scrum

XP (eXtreme Programming) is broad in scope and well define method of all of the agile methods. XP is the only method of Agile which provides deep and profound disciplines for the developers to do their works, like Test Driven development. It is a collection of techniques for day to day development work. While on the other hand, Agile is lightweight process that can be used to manage and control software and product development using iterative, incremental practices. It produces a potentially shippable set of functionality at the end of every iteration.

XP process
Customers define application features with user stories. To develop the system, Team should follow a common coding standard. Team Develops codes as per requirements in each user stories. Designer develop an automated unit tests to run throughout the system. Team can edit the code design as per the requirements as an iteration or refactoring. Team works in a pair programming. They can exchange their code with others, rather having a repository to place codes and all documents which also provides version control to roll back to earlier versions if required. Team members must have to release their work (code) every few hours, they can't hand in the code more than a day. Customer Representative is always there on-site throughout the development process as a part of a team.

Scrum Process
Scrum Master-Is an experience engineer who is responsible for making quick decision based on incomplete data, also responsible for dealing with hurdles that may come up in progress of Team Members; he acts as an interface between management and scrum team.
Product Backlog-Before you do anything else, you must align your development team with the business, nominate a Product owner who will be responsible for approval of the changes in backlog and also prioritized the work.
Scrum Team - Self organizing, committed to work, responsible to achieve deadlines, size of 5 -10.
Sprint - To develop a deliverable a fixed period is available. It includes design, coding, testing and documentation, Scrum Team can add or remove items in backlog.
Daily Scrum Meeting -15-30 minutes meeting on daily bases to discuss about what was achieved?, what will you achieve before next meeting.
Review - Team present the increment against management, customers, users and product owner, team tell story about their work experience. Scrum is very useful methodology for customize the problem by iterations planning and release planning.

Key Differences
Scrum provide management framework to avoid hurdles on the sprint of team. It in a formal way exposes the development activities of the team to non technical staff; it is a project management process not an engineering process. Scrums wrap the management process for helping and guiding throughout the project. It also explains idea about how team will be secure, and it says about the meetings and what those meeting for.
XP is a collection of techniques for daily development work. XP explains techniques like pair programming, test-driven development, lazy programming, Iterations. It contains all of the management ideas of Scrum and plus it contains engineering practice that is missing from Scrum.

Conclusion
Scrum is a subset of XP. Because many Scrum team accept that in their process of developing they are following XP practices like Acceptance Testing, Pair Programming, and Continuous Integration and Test Driven development.

Is Pair Programming Painful?

Key Concepts
The main idea behind pair programming is two developers working on a same coding module. Wherein the roles of the players may switch in fixed durations, also both players do not stand with similar compatibility and knowledge levels, i.e. one of the two would have better programming skills compared to other. This ensures that both programmers are fully aware of what the code is, how it works and why it was thought of this way.

These player's roles change fix durational hours. Generally these roles of players include driver and navigator as in the races. The driver is the primary coder, while navigator sits beside driver and perform reading, checking, some small testing, whilst thinking through problems and where to go next. So when coders lands up in a problem, now we have two people to look for the solution and not only the coder. As the code is being kept constantly reviewed by navigator, its less likely to contain bugs and hacks. Another major advantage of it is, as two people have differing specialities, these skills are transferred between each other.

Positive Aspects of Pair Programming:
1. Problem Solving - Two brains are working instead of one, so if one is doing the programming part, the other brain has already thought off the possible problems it might pop up, and thus it can start thinking for the solution as well
2. Faster Development - While one is at keyboard and coding, other can look for small typographical and silly errors, thus reducing debugging efforts and time.
3. Quality - Having input from two minds definitely improves the design process and reduces the risk of encountering mistakes.
4. Focus - Distractions like surfing on WEB, IM or emails are less likely since that would be rude to the person you are working with. Thus you can have intense focus on your goal, which is a huge difference while working alone.

The Disadvantage of Pair Programming, or rather implementing it in business, is to convince your officials for it, because "Peer Code Review" is other technique in contrast with Pair Programming can also be implemented or can say rather is in used by traditional approach. So if we have code reviewer, why would an organization like to invest more for Pair Programming. Also it demands double hours (i.e. double person for single job, though beneficial in context with effectivity), so it might be thought of as a wastage of resource.

But at the end, I personally would prefer it as a better approach compared to "Peer Code Review", yes though you can say its a waste of resource but at a long run, its NOT, because in "Peer Code Review", it needs to be well studies by someone who was out of the business during coding and thought process, so again reviewer needs to give alot of time to review, which in turn can be more waste of resource compared to Pair Programming.