[Agile development: people are more important than process] Software agile development process

Compared with traditional software development methods, agile development places more emphasis on the role of people in software development, emphasizing rapid iteration, continuous integration, and test-driven development to meet changing business needs.　　The software crisis that began in the 1960s triggered people to think about software development, which led to the birth of the discipline of Software Engineering. Its waterfall approach to software development, which divides software development into several phases such as requirements analysis, design, coding, testing, and maintenance, is still used in most software development organizations today. However, the discipline of Software Engineering and its waterfall development approach has not completely solved the software crisis. How to meet the ever-changing software requirements has always been the problem that traditional software development methods cannot solve.

Agile development has been proposed to solve these problems, and since 2001, more and more developers have begun to accept this approach, and a number of software development and consulting services companies have appeared in the market with Agile development as their main approach. A few days ago, this reporter interviewed Guo Xiao, general manager of ThoughtWorks China, and asked him to introduce how to implement agile development and other issues.

Subverting

Traditional software development methods

Agile development as a development method began in 2001, when more than 10 of the world's most famous software development gurus gathered together to summarize some of the new programming methods that had emerged at the time, and used the word agile to summarize the process of these several similar methods.

"As long as your software development methodology follows the four principles of Agile (i.e., individuals and interactions over process and tools, working software over facile documentation, customer collaboration over contract negotiation, and responding to change over following a plan), it is considered an Agile type of development methodology. For example, ThoughtWorks' own practice integrates Scrum and Extreme Programming, which is a combination of these two approaches." Guo Xiao told reporters.

Guo began working with agile development methods such as Extreme Programming in the 1990s, and then spent more than a decade working in agile development and then in software development management, which allowed him to look at agile at a higher level, a method that is still relatively unknown to most programmers. According to Guo, there are two ideas at the heart of the Agile Manifesto.

One is that people are more important than processes. The biggest difference between Agile and traditional development methods is that traditional software development follows the 20th-century idea of mass industrialized production: each person is responsible for a job on an assembly line, and as long as the process is perfectly designed, people don't matter, which is the realm that Software Engineering is striving for. In fact, software development is a knowledge-based, creative work, it is impossible to completely imitate the assembly line. Agile development emphasizes that a group of people with software development skills form a team, and as to which agile method the team uses, it is entirely up to the team to decide according to its own characteristics. It emphasizes that processes are for people, and values the use of people's maximum creativity.

The other is that software that works is more valuable than documentation. The traditional software development method is divided into requirements analysis, design, coding and other different phases, respectively, by different people responsible for the document in which play the role of the driving force, the different roles through the document to carry out knowledge transfer and interaction. Agile development, on the other hand, believes that documentation is a service for software, and emphasizes rapid iteration and continuous integration so that people in different roles can communicate directly with each other based on the software that has been developed so far. This leads to two benefits: rapid feedback and close collaboration.

"The emphasis on delivery, close collaboration, and rapid feedback is what makes Agile so special, and these characteristics ensure that Agile development is able to meet changing needs." Guo Xiao said, "Whereas the success of software developed using traditional software development methods is largely based on whether the requirements analysis is far-sighted enough to take into account all future needs, which in practice is almost impossible."

Twinning programming

Is it necessary?

We can't talk about agile development without mentioning pair programming, which requires that code should be written by two people at the same time, using the same computer, a keyboard and a mouse. During the interview, the reporter asked Guo Xiao this question: Is pair programming necessary?

Guo Xiao told reporters that pair programming is appropriate in most cases. Under normal circumstances, a programmer doesn't spend all day on the keyboard losing code, he has to think about it, and actually spends only 20-30% of his time on the keyboard. Therefore, two people ***using the same set of computers together does not mean a decrease in efficiency. Agile development requires that while one person writes code, another person reviews that code, evaluates it to see if it is correct, if there is a better way to write it, and then communicates with each other. The quality of code written in this way is much higher than if it were written by a single person.

Another benefit of pair programming is that it reduces project risk. In modern software development, each software developer is responsible for a separate part of the program, and once a programmer leaves or changes jobs, the software development will be very unfavorable. In pair programming, there are at least two people who understand each piece of code, and the risk of personnel changes to the project is much lower.

Another benefit of pair programming is that it helps to pass on knowledge. With pair programming, newcomers to a project can easily fit in without losing code count in the process, and can bring benefits such as knowledge **** sharing.

Guo Xiao adds that while agile development emphasizes agile programming, it does not mechanically require that any code be done in pairs. It's also possible for some very simple, well-known code to be handled by just one person.

In fact, a reporter visited the software development site at ThoughtWorks. The reporter saw that the cubicles that are common at most companies were gone, replaced by large, rectangular round tables. The developers here work in groups of two, and although each has a monitor in front of them, they are all hooked up to the same mainframe, with one of them coding and the other reviewing.

"Our real-world experience has also proven the sophistication of this approach. We've had employees report that pair programming has increased their work stress because when paired, the two will almost never do anything unrelated to their work anymore." Guo Xiao said with a smile.

Agile development

How far can it go?

Agile as a software development methodology is undoubtedly advanced and reasonable, but what is the scope of application of this methodology? Is it suitable for large software development organizations?

"When Agile was formally introduced in 2001, it was argued that it wasn't suitable for large software development teams or for projects with long lead times. In fact, over the years, those claims are breaking down." Says Guo, "And of course Agile itself is expanding so that it can fit into a wider and wider range of domains."

Kuo explained that ThoughtWorks itself has used agile development on 100-person projects. In fact, that's how ThoughtWorks got involved with agile development.

In 1999, ThoughtWorks was just a software development company. When a large project with more than 100 people got bogged down, they had to bring in Martin Fowler and Ward Cunningham, who were known in the industry as the "godfathers" of Agile, to do some consulting work. They got the company out of its predicament by introducing Agile development. This also gave ThoughtWorks a sense of the magic of Agile development methods. Another example is British Telecom (BT), which has a 18,000-strong development team in India and tens of thousands of developers in the U.K. itself and elsewhere, and which now develops almost all of its software projects using Agile methods.

Of course, Agile development as a software development methodology is not a panacea and has some limitations. In other words, there are some prerequisites to ensure the success of agile development.

Says Guo Xiao, "Agile development requires close communication with the customer in order to get constant feedback from the customer. In reality, the customer is usually too busy to take that much time. In addition, there are some product development relies on the product manager to understand the requirements, and he is not really the customer, which makes agile development difficult."

In addition, full customer trust in the developer is a very necessary condition for the success of agile development. The best application scenario of Agile development is that users are constantly coming up with new requirements, and the contract price of the project is constantly adjusted along with the requirements. Guo Xiao said that this is a problem in the actual development process, especially when working together for the first time, customers will be very worried about the final cost of the project. With the company's own development team, this would not be an issue. From this perspective, the biggest market for agile development is the company's internal development team.

"In any case, it has become obvious to us over the past few years that more and more people are embracing the idea of agile development, a trend that can be seen in the number of clients requesting our consulting services. We believe that agile development will definitely establish itself as a place in the field of software development." Guo Xiao said confidently.