Ten Commandments of Successful Software Development
#1 Thou shall start development with software requirements
Every morning, some software developer wakes up with a great new idea for a software application, utility, or tool. Those who go off and start writing code without first considering the requirements for their program are likely doomed to failure. Invest up front in developing your software requirements and you will be starting down the path to successful software development. A software development organization without any requirements management process in place will not repeatedly achieve development success. Here are some tips as to why and how you should develop and manage software requirements for any project, regardless of size.
For starters, if you can’t define the requirements for your software system, you will never be able to measure the success of your development effort. If you were to write a calculator program, would it be successful if it could add two numbers and produce the correct result? What about subtraction, multiplication, and division? Does the calculator need to handle floating-point numbers or just integers? How many digits of precision are needed in results? What should the calculator’s behavior be if a divide by zero is encountered? Should the results be displayed in a textual or graphical format? How long does the result have to be saved after it is displayed? The list goes on. Even in this trivial example, requirements are extremely important to determining the success of the project.
It is very difficult to write good software requirements. Without good requirements precisely stating what a software program is suppose to accomplish, it is very difficult to judge the application’s success, much less complete the project in the first place. One of the main reasons it is so hard to write good software requirements has to do with the nature of human language. English, and for that matter all spoken languages, are very imprecise and leave much to be inferred by the listener or reader. Computers, by their digital nature, are very precise and not easily programmed to infer missing requirements. Therein lies a dichotomy. Think of a requirement statement as simple as "the program shall add the two numbers and display the results." You could raise all the same questions posed in the calculator example in the last paragraph. Even if these questions were answered, more requirements would probably be uncovered during development of the application.
If your software development team is asking questions like those in the previous calculator example, it probably is a good sign. There is no surer failure of a software development project than to have incomplete requirements. Of course the next steps after asking questions and developing requirements are to document them, organize them, and tracking functions that help you do this.
Many development projects actually start with a good set of functionality requirements, such as input this, perform this processing, and output that. What are often left out are performance and other environmental requirements as summarized in Table 1-1. How quickly does the program have to complete the required processing?
Table 1-1 Commonly Overlooked Performance and Environmental Requirements
Requirements Examples
| Processing Speed | CPU speed |
| Memory Capacity | Cache size, RAM size |
| Network Capacity | Network interface card speed, switch/router bandwidth |
| Persistent Storage | On-line disk capacity; tape backup capacity |
| Internationalization Support | Will the application be deployed in different countries or in different language? |
| Minimum Display | Monitor size and resolution; number of colors supported |
| Financial | Budget and schedule |
| Environmental | Power requirements, air conditioning, special temperature or humidity requirements |
How much RAM or disk space can it use? Does the software have to support internationalization for worldwide use? What is the minimal display size required? Environment related requirements are becoming increasingly important, especially with the advent of cross-platform development environments such as Java. Java truly provides a write-once run anywhere environment ranging from smartcards to workstations to mainframes. A Java applet that looks great on a workstation’s 21" color monitor, however, may look much different on the 4" screen of a monochrome personal digital assistant (PDA). Finally, don’t forget budget and schedule requirements. In gathering these requirements, the reasons for the second commandments should become very clear to you.
#2 Thou shall honor thy users and communicate with them often
Their own developers do not use most software applications; the intent is for it to be used by the developer’s customers, clients, and end-users. This implies that someone in your development organization had better spend a lot of time communicating with users so that their requirements can be correctly understood. In the calculator example from the first commandment, a developer may be perfectly happy with the four basic arithmetic functions while the user would like a square root function or a memory function. What the developer thinks is a complete set of requirements isn’t necessarily so.
Moving from a trivial to a real world example, an enterprise-wide IT application may have many types of users, each with their own business requirements. Take a payroll system for example. One type of user is the employee, whose requirements include getting paid the correct amount in a timely fashion. A second type of user is a manager, who wants to be able to administer salary increases and track budgets. A third type of user might be the HR administrator, who wants to compare salary ranges across an entire organization. Each user type will have unique requirements.
The second part of this commandment focuses on the word "often." Frequent communication is required, among other reasons, because English (or any modern language) is an imprecise language. Communication with users only starts at the requirements definition phase. A developer may have to discuss a requirement with a user several times before the true definition of the requirements is captured. In addition, user requirements are likely to change often, and indeed several requirements may even conflict. Frequent communication with users gives the developer early notice of requirements changes the user is considering.
A successful software development organization has established processes for frequently communicating with users during all stages of the development process. The sooner an incorrect or missing requirement is discovered, the easier it is to fix the problem. Many successful development organizations have made customer advisory teams an integral part of the software development process. Such customer teams participate in all stages of development from initial requirements gathering to production acceptance signoff. The Web-Centric Production Acceptance (WCPA) process (see our book titled Software Development: Building Reliable Systems, ISBN 0-13-081246-3) presented is another vehicle for bringing users and developers together and promoting and instilling good communication practices.
#3 Thou shall not allow unwarranted requirements changes
While user requirements do often change, it is the job of the development organization to manage these changes in a controlled fashion and assure that requirements do not change or grow unnecessarily. Pity the poor programmer who started off writing a basic arithmetic calculator, agreed to add square roots and a few other user requested functions, then a few more, and soon had the task of developing a sixty-five function scientific calculator. Modifying or adding new requirements can happen for many reasons, not the least of which being the failure to honor Commandments One and Two.
Another reason requirements grow beyond their original scope is simply that software is so easy to change compared to hardware. No one would purchase a calculator at the local electronics store and then expect the manufacturer to add additional transistors to the calculator chip to implement a new function. If the calculator were a software application, no one would think twice about the ability to add a new function.
Perhaps an even more common reason that requirements change is due to the programmers themselves. Many a programmer has accepted a new user requirement not based on valid business reasons but simply to please a user. Other times the software may be fully functional and pass all unit test requirements, but the programmer just wants to add one more feature to make the application "just a little better." Good developers always want their code to be perfect in their own eyes. The cost of making even simple changes, however, is minor compared to the cost of the retesting and re-qualifying that may result.
This does not mean to say we are against iterative development. In Chapter 10 (Software Development book), "The Software Life Cycle", the use of iterative or spiral development is prominently discussed. Even in a spiral development model, however, new requirements are introduced at the start of new iteration, not continually during the development process. Since requirement changes impact project budget and schedules, only allowing changes at set points in the software life cycle allows time to trade off the value and validity of each new proposed requirement against its cost. Meanwhile, developers can complete each stage with a frozen set of requirements, speeding the total development cycle.
Object-oriented and component-based software technologies help further isolate the impact of many requirement changes. Still, requirement changes are a constant problem for many software projects. Part of this is the developer’s fault. Luckily, managing requirements is mainly a process issue rather than a technical one. Here are some ways to help prevent requirements from constantly expanding beyond their original scope:
- Document all user requirements, allowing the users to review the completed requirements document and agree to its completeness;
- Get users to agree up-front that future requirements changes will only be accepted after being evaluated for schedule and budget impacts;
- Practice iterative development. Get users and developers to understand that the first version is not the final version. That "one last change" can always wait for the next version. Many a software system has suffered unexpected delays because a simple last-minute change rushed through just before release broke huge parts of the system.
#4 Thou shall invest up front in software architecture
Every morning, some developer goes to work with software requirements for a new application in hand and starts writing code. For those who go off and start writing code without first developing software architecture, their programs are likely doomed to failure. Invest up front in your software architecture and you will be starting down the path to successful software development.
Developing architecture for an industrial-strength software system prior to its construction is as essential as having a blueprint for a large building. The architecture becomes the blueprint, or model, for the design of your software system. We build models of complex systems because we cannot comprehend any such system in its entirety. As the complexity of systems increases, so does the importance of good modeling techniques. There are many additional factors to a project’s success, but starting with a software architecture backed by rigorous models is one essential factor.
In the face of increasingly complex systems, visualization and modeling become essential tools in defining software architecture. If you invest the time and effort up front to correctly define and communicate software architecture, you will reap many benefits including:Accelerated development, by improved communication among various team members:
- Improved quality, by mapping business processes to software architecture;Increased visibility and predictability, by making critical design decisions explicit.
- Here are some tips on how and why to always start your software development project with software architecture.
- Start with a minimum yet sufficient software architecture to define the logical and physical structure of your system. Some sample activities performed are summarized in Table 1-2.
Software architecture is the top-level blueprint for designing a software system. To develop good software architecture requires knowledge of the system’s end users, the business domain, and the production environment, including hardware and the other software programs the system will interface with. Knowledge of programming languages, operating systems, develops good software architecture. As software systems grow more and more complex, ever more knowledge is required of the software architect. Object-oriented and component-based technologies may simplify individual programs, but the complexity typically remains at the architectural level as more objects or components and their interaction must be understood.
Table 1-2 Software Architecture Activities
Activity Example Architecture Level
| Gather user requirements | Generate use-case examples | Logical architecture |
| Document sample user activities | ||
| Create class diagrams | ||
| Create state diagrams | ||
| Create sequence diagrams | ||
| Create collaboration diagrams | ||
| Start design and production acceptance | Define packages and components | Physical architecture |
| Define deployment environment |
There are no shortcuts to designing good software architecture. It all starts with a small number, perhaps one to three, of software architects. If you have more than three architects working on a single program’s software architecture, they probably are not working at the right level of detail. When software architecture delves too deeply into detailed design, it becomes impossible to see the whole architecture at a top level and properly design from it.
Most software applications are much more complex than the makers of GUI development tools would sometimes like you to believe. Every application should be built around a software architecture that defines the overall structure, main components, internal and external interfaces, and logic of the application. Applications that work together in a common subsystem should adhere to an architecture that defines the data flow and event triggers between applications. Finally, applications that run across your entire organization need to follow some set of minimal guidelines to assure interoperability and consistency between applications and maximize opportunities for reuse of components.
Software architects should always be designed from the top down. If you are going to implement a multi-tier software architecture across your IT organization, its nice to do this before you have lots of components written which can only communicate with other applications on the same host. Start by developing your organization’s overall application architecture. Next, you should define the system architecture for the major systems that will be deployed in your organization. Finally, each application in every system needs to have its own internal software architecture. All of these architectures should be developed up front before you develop any production code or invest in any purchased software packages. The notion of completing software architecture up front does not contradict the spiral model of software development that utilizes prototyping and iterative refinement of software. Rather, prototyping should be acknowledged as an essential step in defining many parts of your architecture.
Trying to design a global set of every reusable component you think you might ever need is a losing proposition. You only know which components will be useful with lots of real experience delivering systems. If you don’t prototype, you don’t know if what you’re building is useful, tractable, and feasible, or not.
#5 Thou shall not confuse products with standards
A common mistake made by IT organization is to confuse products with standards. Standards are open specifications such as TCP/IP or HTML. Standards can either be de facto or official. De facto standards, while not endorsed by any standards body, are widely accepted throughout an industry. Official standards are controlled by standards, bodies such as the IEEE or ISO. Products can implement specific standards or they may be based on proprietary protocols or designs. Standards, because many vendors typically support them, tend to outlive specific products. For instance, in the early 1990’s, Banyan Vines was one of the top two network operating systems for PC’s. Today, suffering from its own proprietary protocol, Banyan Vines has been relegated to a niche player in the network operating system market.
If your IT organization chooses to standardize on a product, say Cisco routers for network connectivity, you should not do so until you first standardize on a standard protocol for network connectivity, such as TCP/IP. Here are some common mistakes IT organizations make when defining their application, system, and software architectures.
- The application architecture is defined at too high a level. Some CIO’s make the mistake of declaring Windows NT (or Unix, or Mainframes) their corporate application architecture for an IT organization. Even the various third party programs designed for NT, or any other operating system, do not define all the characteristics of how to run a business. This is not to say that a corporation might not standardize on NT and use it wherever possible in its IT infrastructure, only that application architecture requires a finer granularity of detail. In general, application architectures should not be so specific as to be tied to particular products.
- The application architecture is defined at too low a level. Oracle Version 8 is not application architecture – it is a specific version of a vendor’s database product. Once again, application architectures should not be product specific. A better architecture phrase would be, "relational databases that implement the SQL standard." Once again, this may not preclude a company from deciding to purchase only SQL DBMS systems from Oracle, but specific product choices should be made only after the underlying standards decision has been made.
- System architecture does not address how the system is going to be tested. Many software projects have wonderfully elegant (from a computer science perspective) architectures that result in projects that fail miserably because no attention was ever paid to how the system was going to be tested. One of the most commonly overlooked test factors is performance testing. System architecture must take into account how a system is going to be fully exercised and tested. This is especially relevant when designing multi-tier applications. For instance, in a three-tiered system, the architecture may allow for individual testing of components in each of the three tiers, but may not allow for end-to-end system testing verifying the correct interoperation between all three tiers. An equally bad architecture allows for end-to-end testing without allowing for testing of components in each individual tier. There is no worse plight to know that your whole system isn’t operating successfully and have no way to isolate what component is causing the problem.
- Software architecture does not consider production rollout of the application. Besides taking into account how an application will be tested, the process of rolling out an application into production needs to be considered in your software architecture. Many great systems have been designed that were never fielded because the infrastructure to support their widespread use was not available. The Web-Centric Production Acceptance process specifically addresses the production rollout process for web-centric applications.
#6 Thou shall recognize and retain your top talent
Too many software development books concentrate on technology or management practices. At the end of the day, a lot of your success in software development will come down to who you have working for you and how happy they are in their work. You can have the best technology and organize your team in the best way possible, but if you have the wrong team it won’t do you much good. Another surprise, given the effort so many organizations put into recruiting talent, is their failure to recognize and retain that talent after they join the organization.
Organizations that are successful at retaining their top talent start by recognizing their top talent. There are plenty of metrics that can be gathered around a developer’s productivity and quality. Don’t forget, however, more subjective criteria as summarized in Table 1-3. Who are the developers who always show up at other code reviews and make constructive comments? Who is known as the "goto" person when you have a tough bug to find? Which developers really understand the business you are in? Who has the best contacts with your customers? Be sure not to concentrate 100% on hard metrics and overlook such factors as these. Once you know whom you want to keep around, go about thinking of ways to make it happen.
Table 1-3 Traits of Successful Developers
Skill Dimension Trait Example
| Operating system knowledge | Understands operating system principles and the impact of OS on code design choices | |
| Networking knowledge | Understands networking infrastructure and matches application network demands to available infrastructure | |
| Data management | Understands how and when to use databases, transaction monitors, and other middleware components | |
| Hardware | Knows the limits of what can be accomplished by the software application on various hardware configuration | |
| Business | Understands the business | Can differentiate between "nice to have" requirements and those that are essential to the function of the application |
| Market knowledge | Keeps up-to-date on developers tools, frameworks, and hardware | |
| Professional | Written and verbal communication | Effective presenter at code reviews; documentation is easy to read and understand |
| Teamwork | Participates actively in other’s code reviews | |
| Flexibility | Can work well on a wide variety of coding assignments | |
| Reliability | Always completes assignments on time; strong work ethic | |
| Problem solving skills | Viewed as a "goto" person for help in solving difficult software bugs |
Throughout most of the 1990’s, demand for skilled high technology workers has far exceeded the supply. It is easy to throw software developers into this general category and assume good developers are no harder to find than other high tech workers. Based on our experiences, we believe good software developers are even scarcer than good IT personnel in general. Just consider some of the numbers. The Java language was introduced as a new programming language in 1995. By late 1997, IDC estimated that there was a worldwide demand for 400,000 Java programmers and that this would grow to a need for 700,000 Java programmers by the year 1999. While retaining existing developers to program in the Java language has filled much of this demand, it still represents a tremendous outstripping of the supply of knowledgeable Java programmers.
Developer skill, more than any other factor, is the largest single determinant to the outcome of successful software projects. This is reflected in software costing and scheduling models, most of which place higher weighing factors on developer skill than all other factors, including even project complexity. In other words, skilled developers working on a complex software development project are more likely to produce a successful application than lesser skilled developers working on a simpler project. It is no accident, therefore, our Software Development book devotes a large part of its text to describing what makes a good developer (Chapter 5), how to hire one (Chapter 7), and how to retain your developers after they are hired (Chapter 8). Studies have shown that top developers can be two to three times more productive than average developers and up to one hundred times more productive than poor developers. This wide range of productivity and its standard deviation is higher than for any other profession. Good developers not only produce more lines of code, their code has fewer errors, and the code they produce is of higher general quality (i.e., it performs better, is more readable, is more maintainable, and exceeds in other subjective and objective factors) than code produced by average or poor developers.
One false belief we have heard from many software development managers, especially those without a development background, is the notion that as development tools become more advanced, they "level the playing field" between average and great developers. Anyone who has ever attended a software development-related convention has seen slick demonstrations showing how "non-programmers" can use a development tool to quickly build an application from scratch. Modern development tools, especially Integrated Developments Environment (IDE’s) addressing everything from requirements definition to testing, certainly help developer productivity. This is especially true in the area of graphical user interface code. Even with the best of IDE’s, however, there remains a highly intellectual component to software development. The best software requirements, the best software architectures, and the most error free code continue to come from the best software developers and software architects.
Rather than leveling the playing field, our experiences have shown that good IDE’s, used as part of the development process, increase rather than decrease the difference between average and great developers. There is often a compounding effect as an unskilled developer misuses a built-in function of the IDE, introducing bugs into the program, while never gaining the experience of thinking out the complete solution. We are not, of course, by any means against the use of good IDE’s or the concept of code reuse. It’s just that neither of these are a substitute for developer skill.
#7 Thou shall understand object-oriented technology
Every key software developer, architect, and manager should clearly understand object-oriented technology. We use the term "object-oriented technology" versus "object-oriented programming" because one does not necessarily imply the other. There are many C++ and Java programmers who are developing in an object-oriented programming language without any in-depth knowledge of object-oriented technology. Their code, apart from the syntax differences, probably looks very much like previous application they have written in FORTRAN, C, or COBOL.
While object-oriented technology is not a panacea for software developers, it is an important enough technology that the key engineers in every development organization should understand it. Even if your organization does not currently have any ongoing object-oriented development projects, you should have people who understand this technology. For starters, without understanding the technology you will never know if it is appropriate to use on your next project or not. Secondly, due to the long learning curves associated with object-oriented technology, organizations need to invest in it long before they undertake their first major project. While object-oriented programming syntax can be learned in a few weeks, becoming skilled in architecting object-oriented solutions usually takes six to eighteen months or more, depending on the initial skill set of the software engineer.
#8 Thou shall design web-centric applications and reusable components
As in the case of object-oriented programming, not all software architectures will be web-centric. With the explosion of the public Internet, corporate intranets and extranets, however, web-centric software is becoming more and more universal. This changes not only the way you design software, but also some of the very basic infrastructure requirements as well. Here are some of the infrastructure components needed for a typical web-centric application:
- Database server. A web-centric application will typically access one or more corporate databases. Unlike a two-tiered client-server application, however, a web-centric application is less likely to access database directly. More commonly, a web-centric application would access some sort of middle-tier application server containing the business rules of the application. The middle-tier application would then communicate with the database server on behalf of the web-centric client. There are many advantages to such a multi-tiered approach, including greater application scalability, security, and flexibility.
- Application servers. In a web-centric architecture, application servers implement the business logic of the application. In many cases, this is programmed using the Java language. From a Java program, the Java Database Connectivity (JDBC) API is most often used to connect back to the central database. Specialized application servers may offer services such as DBMS data caching or transactions. A single business function is often broken down into components that execute across many applications servers.
- Web servers. Web servers are used to store and distribute both Java applications and web pages containing text and graphics. Many advanced applications will generate web pages dynamically to provide a customized look and feel.
- Caching proxy servers. These servers, while not explicitly part of the application, are typically located strategically across the network to cut down on network bandwidth and provide faster access times to web-based data and applications.
- Reverse proxy server. A reverse proxy server is typically used to provide remote users secure access over the Internet back to their corporate Intranet.
- Web clients. Until recently, a web client meant either Netscape’s Communicator (or Navigator) browser or Microsoft’s Internet Explorer browser. Today, a web client could still be one of these browsers, or it could be any of the following:
- An HTML rendering JavaBean component in your application
- An applet viewer built into a Java Development Kit (JDK)
- A Java application
- A collection of functions built directly into the operating system
One of the main advantages of web-centric design is that it starts taking IT out of the business of supporting heavyweight clients. In fact, most new operating systems ship with one or more bundled web browsers so no additional client installation is required for a web-centric application. Even if you are deploying to older desktops without a bundled web browser, the popular browsers are available for free and easily installed. If a web-centric application is designed correctly, the end-user client really doesn’t matter, as long as an HTML rendering component and Java Virtual Machine (JVM) are present.
If there is any disservice that the web has brought to software development, it is that inexperienced managers may believe that the web has trivialized web-centric software development. True, almost any word processor today can spit out HTML code and dozens of development tools promise "point and click" generation of Java codes while the web makes software distribution a non-issue. All of this has allowed web-savvy organizations to develop new applications on "Internet time", several times faster than using traditional client-server environments. It has not, however, by any means, trivialized software development. From requirements definition through production acceptance, the same disciplines that apply to client-server development hold true for web-centric development. We remind developers of this continually throughout our Web-Centric Production Acceptance (WCPA) process, presented in Chapter 13.
While embracing web-centric design does not necessarily require using reusable components, it certainly is a good time to start. More and more development organizations every day are investing in the design and development of reusable components. Chapter 17 of our Software Development book discusses component-based software development in greater detail, along with several of the popular component frameworks. It is such frameworks that have fostered the popularity of reusable components. Consider some of the reasons why more and more people are investing in reusable component-based design.
It can take longer and be more expensive to design and implement a given function as a reusable component than as a non-reusable one. The savings only come when the component is reused. Especially with web-centric design, however, you will find your developers reusing well-designed components more and more. This reuse is facilitated by component standards such as JavaBeans components integration. The cost trade off, therefore, is to compare the overhead of reusable design with the average number of times a component is expected to be reused. A reusable component, on average, might cost from 10% to 25% more to develop. Few development managers today could justify a 25% cost and schedule overrun just to save the next project money. However, properly implemented, reusable components can begin saving project money today.
- If you invest in the design of reusable components and an accompanying framework, you will undoubtedly find components you can reuse from elsewhere in place of some of the code you would otherwise develop.
- It is likely components developed on your own project can be reused elsewhere in the organization.
- You can buy and sell components (either externally, or by exchanging with other development groups inside your company).
- Well-built components are much easier to swap out and upgrade.
#9 Thou shall plan for change
The best developers and architects plan for change during all phases of the software life cycle. During the course of an average one year development cycle, not only will the design be subject to change, but so too will the user requirements, the development tools, the third party software libraries, the DBMS system, the operating system, the hardware, the network, the programmers, and many other aspects of the application that cannot possibly be foreseen or otherwise planned for. Some aspects of change, such as a new release of the operating system, can certainly be planned for by discussing schedules with the vendor and making a decision whether a new release should be installed or not. Sometime during the application’s life, however, the underlying operating system will probably have to be upgraded so it’s really just a matter of when changes such as these are done. In either case, you still have to plan for the changes.
The longer the expected project lifetime, the more important it is to plan for change. The Cassini mission to Saturn, operated by JPL, was launched in October of 1997. With any luck, the spacecraft will enter orbit around Saturn in 2004. The JPL engineers running the Cassini ground station definitely must plan for changes in hardware and software prior to the spacecraft’s encounter with Saturn in 2004. Any company that designs a long lifetime product with an embedded hardware and software component must pay careful attention to planning for change. Back down on earth, for instance, every high-end Xerox printer contains an embedded workstation controller. Typically these workstations are commercial off-the-shelf products with an average lifespan of eighteen months. Xerox high-end printers are designed for five to ten or more years of continuous operation. Xerox must plan for change in the embedded workstation components for each of its printer lines.
There are many ways to plan for change. For starters, allow extra budget and schedule in your project for unforeseen changes. At the start of the project, work to clearly identify all risk items that could lead to a possible change somewhere in the future. During the design, look for ways to mitigate the risk of a change further downstream. At the coding level, look for ways quickly and easily set up code to be adapted to new situations and events within your business. For instance, use tabular definitions whenever possible versus "hard coding" these parameters into your code. Here is a real life example of two companies that implemented the same application, and how they did (or didn’t) plan for change.
We worked with two companies of about the same size that implemented the Oracle Financials application package in early 1997. In both companies, various business units wanted to modify the standard financials applications to meet some unique need of the business unit. Much of Oracle Financials operation is table driven with those tables residing in a DBMS. The IT department thus entertained each business unit’s request as most of the changes could be done by a database administrator with little or no coding. The first company went ahead, approved, and implemented the customization for each business unit. In the second company, they planned ahead for change and considered what the impact of making the customizations would be next time Oracle Financials came out with a major upgrade. The latter company decided the marginal business benefits of providing the customization was outweighed by the future costs to maintain these upgrades.
Well, as you might guess, in 1998, Oracle Financials released a major revision, based on their Network Computing Architecture (NCA). With NCA, the Oracle Financials client would be deployed via a web browser, versus loading client software on each desktop requiring access to the application. NCA offers tremendous business advantages to corporations through reduced application administration costs along with the improved functionality that is bundled into the release. The company who did the customization is still evaluating how to roll out Oracle’s NCA as the customization they performed prevents a simple upgrade and the DBA’s who did the initial customization are not yet trained on NCA. By contrast, the second company, with no extensive customization, was able to complete the upgrade to NCA in a single weekend. They have been enjoying the added functionality and client administration cost savings ever since.
#10 Thou shall implement and always adhere to a production acceptance process
Mentioned several times already in the first nine commandments, our last commandment centers around the use of the Web-Centric Production Acceptance (WCPA) process presented in Chapter 13. In our book we focus on the WCPA as tailored for web-centric applications. The WCPA is really a superset of the Client-Server Production Acceptance (CSPA) process presented in Building the New Enterprise. Most of the WCPA will be useful even if you are not yet designing web-centric applications. Production acceptance takes an application from the early stages of development and into a production status. However, planning for WCPA really begins at the first stages of the software development process. This is where we first start getting users involved, and keeping them involved throughout the development process through the use of customer project teams. At the same time, the development team needs to start getting IT operations involved. The WCPA shows that it is never too early to start getting both users and operations involved.
One of the reasons we developed the WCPA is to serve as a communications vehicle. All too often, development organizations are isolated from the business groups who will use their application and the operations group that will run and maintain them. Proper use of the WCPA will help promote and instill good communication practices. Just as iterative development is a key software development process, so it is iterative and ongoing communications with operations and with users.
This commandment is important because without a closely followed WCPA your business may lose valuable revenue or even customers because your web-centric application does not function as expected. Perhaps one of the earliest examples of a WCPA can be traced to Netscape’s web server when they first opened for business in mid-1994. When designing their web site, Netscape engineers studied the web server load of their competitor at the time, the Mosaic web site at the National Center for Supercomputer Applications (NCSA). The NCSA site was receiving approximately 1.5 million web "hits" a day at the time. Netscape engineers thus sized their web site to initially handle 5 million hits a day during its first week of operation. Luckily, Netscape had planned their web site architecture to be scalable, and were able to add additional hardware capacity to handle the load.
The success of the WCPA process is also related to the robustness of your software system’s architecture. An even greater percentage growth than Netscape’s occurred at AT&T Worldnet. AT&T had expected to sign up 40,000 customers for their Worldnet Internet service during its first month of operation and had designed the site accordingly. During its first month of operation, Worldnet registered 400,000 new subscribers, ten times the expected amount. Luckily for AT&T, they had architected the system for growth and put in place the equivalent of a WCPA process. As a result, all new subscribers were able to start receiving service with few complaints of busy signals on dial-in attempts (in contrast to some other well-known Internet services).
A great example of what happens when you don’t follow a complete WCPA process occurred at a major U.S. bank during 1998. The bank was planning an upgrade to its Internet home banking service. Prior to the upgrade, the bank used a load-balancing scheme to distribute users to a number of front-end web servers, all of which connected to the bank’s mainframe back-end systems. As part of the upgrade process, the bank was planning to let all users change their login ID and password, thus allowing more individual flexibility than the previous bank-generated login ID scheme. The first time a customer logged in after the upgrade, he would be required to select a new login ID and password or confirm keeping the old login ID. This process was delegated to a separate new web server in order to not interfere with any of the software on the existing load-sharing servers. The bank, of course, did have some production acceptance processes in place and tested the entire web-centric system. On the first day of production, users started to complain of extremely long access times. Unfortunately, the bank had not taken into account the potential bottleneck of funneling all users through the single server while they were queried for potential login ID changes.
While no process can guarantee a new production system will function 100% correctly, web-centric applications require new kinds of planning like that covered in the WCPA. Not only are user loads on the Internet much more unpredictable, web-centric applications typically involve the interaction of a much larger number of software and hardware systems.
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