By Susan Dart
Web content involves many types of data: files, documents, graphics, streaming audio/video, source and binary code, and component libraries. The configuration management tool must cater to these as well as to their compilers and interpreters and the associated metadata.
Metadata includes information such as:
- The differences between the content and its representation: template, theme, or format.
- Its external (page-to-page) versus internal (intra-page) structure.
- Link relationships.
- Associated tasks or transactions.
- Security rights.
- Tool associations.
- Bill-of-materials (such as how the object was created: tool versions and options or parameters).
- Audit trails.
- Data validation and handler rules.
- Association to caching algorithms.
Configuration management is "a disciplined approach to managing the evolution of software development and maintenance practices, and their software products." (Ovum Evaluates: Configuration Management Tools, Dart, Susan, Ovum Limited, 1996.) Most companies institute CM once maintainability problems arise. But many problems could be avoided altogether by using CM practices or tools early on.
The first article explained why configuration management allows safe growth of Web applications. This report will examine the goals of CM and discuss what vendors are offering. This content originally appeared in Wiesner Publishing's Software Magazine and appears on TechRepublic under a special arrangement with the publisher.
What is CM?
A typical CM textbook defines CM as:
- Identification: Uniquely identifying all objects.
- Control: Version control of all objects including configurations and baselines.
- Status accounting: Tracking the state of all work on objects.
- Verification and validation: Ensuring that a process is followed and an audit trail is kept.
But these are the minor goals of CM.
The real goals
What industry really wants to achieve with CM is:
Cost-effective production: Fast, reproducible builds of software releases.
Quality automation: Ensures automatically that all testing, notifications, signoffs, and reviews are done before a release is distributed.
Teamwork optimization: Enables teams to work in parallel effectively, such as on the same files or releases simultaneously.
Enabling change: Containing the explosion and complexity of changes.
These goals are also those of Web development teams. Two big decisions need to be made for CM adoption: What CM infrastructure strategy suits us best? And what are my CM requirements?
In a typical corporate infrastructure, autonomous business units (BUs) and project teams, along with the IT department, contribute content to the corporate Web site. Here is a typical CM strategy: The content experts (such as the BUs), are given a "lite" form of CM so that their work has minimal protection with, say, version control. Such groups do not want to be bothered with CM. The other groups (such as IT and project teams), who do more traditional application development, are given a "heavy duty" CM tool based on their needs.
CM requirements depend on infrastructure strategy and the type of Web application being built. For instance, an informational type of application contains static content, so it has no requirements to support dynamic content. Also, the rate of change will be low, and the urgency and priority of most changes will not be mission-critical or high; nor will there be a high volume of content to be changed.
Vendors are struggling with the definition of a Web application. For instance, is Web content a different notion from a Web application? Typically, Web content is seen as separate from the Web application.The author's view is that every Web site is an example of an application: Some are very simple document display sites, whereas others are complex, large-scale dynamic applications. Each company has its own demands or requirements on its Web applications. While initially most Web sites were "brochureware," now they are shopping malls, customer service centers, information exchange centers, analytical centers, and communities.Web applications can be broken into 12 types. The criteria were based on how one would perform CM on that application. The academic community typically thinks of two types: information-based and application-based. This is too limiting when thinking about how CM is used to mitigate the Web crisis. An important issue, which everyone can agree on, is that creating a Web site should be viewed the same way as creating a software application that will eventually be supported by Web engineering techniques, which can be taught.
CM tool menu
CM vendors are carefully examining their Web strategies. Selling to the Internet audience changes their sales and marketing approach because that audience is not the traditional software manager and developer, but rather content experts such as graphic design artists and public relations professionals. This audience does not know what CM is, why it is needed, or what a release is. But once they start losing data, publishing mistakes, and seeing other problems that CM fixes, it becomes more relevant. Either they will buy a CM tool that works with their content editing tools, or their content tools will have CM capabilities embedded.
The CM vendors have done considerable thinking about how to handle Web content. Many have "Webified" their tools. For instance, most tools provide access to some or all of their CM functionality via a browser, and most provide simple check-in, check-out integrations with a few of the popular content authoring tools. Some CM tools allow CM information to be published directly to any Web site. For example, the PVCS Tracker from Merant, Mountain View, CA, publishes metric reports and also allows anyone to submit a change request via a browser without having a license.
Some vendors have geared their tools' interface for content authors, such as WebSynergy and WebPT from Continuus Software, Irvine, CA. These tools, depending on the role of the user, present an alternate interface and hence, CM features appropriate to that role.
StarBase, Santa Ana, CA, has added functionality to its CM tool, StarContent, which is transparently integrated with the Windows file system. It works as an extension of the file system such that content authors do not need to learn about CM—StarContent intercepts the changes and flags the file as changed. The CM repository appears as another drive in Windows Explorer.
Some tools have not yet publicly presented a specific Web approach, such as ClearCase from Rational Software, Cupertino, CA; SourceSafe from Microsoft, Redmond, WA; or TrueChange from TrueSoft, Waltham, MA.
Ideally, vendors' tools can support one end of the CM "lite"/CM "heavy" infrastructure spectrum. For instance, Web Integrity from Mortice Kern Systems and StarContent from StarBase Corp. can be used for CM "lite," whereas Continuus and PVCS Dimensions can be used only for CM "heavy." Only Merant's PVCS product line consists of products to support the full spectrum: Version Manager/Tracker for "lite" and Dimensions for "heavy." (Merant bought out several companies and products formerly known as Intersolv's PVCS and SQL's PCMS, and has integrated the repositories, enabling full spectrum support.)
All the CM tools can be used without their Web enhancements. A very simple capability that probably every Web developer will need from a CM tool for Web content is the ability to execute a change across all Web pages with one command. PVCS Dimensions has a "find and replace" command that searches through all content files and performs a universal change. The CM system keeps an audit log or history, tracking the change.
Of course, Web teams will most likely look for their CM solutions elsewhere—not in a CM tool, but in their Web authoring tools, of which there are many with varying degrees of sophistication and ease of use. The large-scale Web authoring tools can be referred to as "Web content management" (WCM) tools.
Susan Dart is a strategic consultant for configuration management and author of the forthcoming book Containing the Web Crisis with Configuration Management (Artech House, U.K.). More information can be found in the paper "Web Content Management: Challenges for Web Systems, Proceedings of the International Symposium on CM," Dart, Susan, Springer Verlag, 1999. For further information about developing requirements, and performing tool selection and deployment, refer to "Achieving the Best Possible CM Solution," Dart, Susan.Have you used one of the CM tools this article describes? Share what you’ve learned. Post a comment below or send us some mail.