repository and copying them to a private workspace outside the VC system. Typically, all source files must be copied -- even those that the developer doesn't plan to change.
As he or she completes the changes, the developer checks the revised source code back into the vault. In an active project, this results in many copies of each source file. Because programmers change the files outside of the VC system, they cannot coordinate simultaneous updates to the sources. This limitation often results in such problems as developers overwriting each other's changes, and it limits the opportunities for concurrent development.
Contemporary development demands
have put even more pressure on this older approach. For one, teams no longer work on a single source base; parallel development, where many development teams work on the same source base for both maintenance and future product development, is common
.
In addition, the chance of a single software manufacturer's producing products that can work together on Unix and PC platforms alike is much higher today. Similarly, the availability of scalable OSes that can run on RISC and Intel platforms alike, such as Windows NT, has encouraged manufacturers of high-end enterprise tools to produce versions that accommodate both types of platforms.
More robust VC tools allow developers to track all changes made to every file in a project. Furthermore, they manage access to different components of a project, enabling controlled sharing of code among the (possibly several) development teams that are involved. In a large-scale effort, where programming teams might be at different geographical sites, a comprehensive VC system enables each team to view the others' changes while maintaining control over access to the source files.
A configuration management (CM) system includes the functions of an advanced VC system and expands them in several important area
s. Instead of simply allowing a developer to create a workspace by checking out source files, a CM system manages that workspace to the benefit of the entire project. A developer working on one section of code, for example, might want to test current changes for compatibility with the latest code revi-sions from one team while remaining isolated from the changes that are being implemented by another team.
In addition, a vigorous CM system includes such build management features as minimal rebuilding, documenting the components that make up each software build, and making available the entire file environment of any build. The reliability and reproducibility of the build environment are critical for quality control and for tracing the genesis of any bugs that are discovered later in the testing process.
Support and enforcement of organization-specific policies and procedures are the final tasks of a modern CM system. Because such a system holds key information about a project, including the status
of and relationships among its individual components, it's uniquely able to generate status reports, identify and track problems early in the development cycle, and project forward to milestones.
The New Frontier
The importance of VC as a part of the software development process has evolved dramatically from the earliest "who's got the source floppy?" stage. Yet many software developers continue to use homegrown VC systems that grew along with their products. In a recent survey, only 5 percent of the software companies polled worldwide reported that they used a commercial VC/CM product.
This may be in part because compilers and visual design environments, particularly in the Windows environment, increasingly include their own somewhat-limited VC capability. The simplicity of these built-in and add-on facilities makes them more approachable than full CM packages. However, simplicity comes at a price: lack of process control, lack of an automated workspace setup, and limited scala
bility.
Clearly, times have changed and the development process has evolved. Powerful new features are appearing in the
current crop of VC/CM tools
in an effort to keep pace with today's software development requirements. Although many features of VC/CM tools are touted by their providers,
a few key areas of
VC and CM products are crucial.
Development Environment Integration
Version control must be readily available and easy to use from the comfort of the development environment. Nearly every VC/CM solution provides (or is scheduled to provide) integration with common development environments. Intersolv's PVCS and Mortice Kern Systems' Source Integrity, for example, support many of the popular integrated development environments (IDEs), including Delphi, Visual Basic, and Visual C/C++.
To encourage integration, many VC/CM providers publish a set of APIs that third-party applications can use to incorporate VC/CM features into
their applications. If your development project intends to use, or could benefit from, such features, a published API should be high on your feature-set checklist. Xcc Software's RCE, for example, is delivered as a set of APIs in library (DLL or LIB) form.
Low-level integration of VC and CM opens up other doors that might move VC/CM tools into common usage. For instance, a developer charged with creating a VC system for software might leverage that work by developing a modified system to track drawings in a CAD/CAM system or documents in a marketing group. For these applications, an API-based system may provide the most flexibility. VC/CM manufacturers see this situation emerging. By building task flexibility into a system, they can market their tools as a single enterprise-wide management system.
Cross-Platform Support
Now that PC compatibles, Macs, and Unix workstations can all serve as common development platforms within the same corporation, VC/CM solutions must address the
needs of a heterogeneous environment. Consider the range of computer systems attached to the Internet: For the most part, the hardware details are completely transparent to the user.
Although an enterprise network supports a number of heterogeneous platforms, cross-platform support for development tools is a relatively new concept. Whether a developer is using Windows, Windows 95, Windows NT, OS/2, DOS, Unix, or Mac OS, development tools should function in harmony.
Diverse platforms will increasingly have to interoperate. However, the different compilers, linkers, and OSes that are used in a heterogeneous development environment continue to make this an elusive goal -- but one that is brought closer by advanced VC/CM systems.
Atria's ClearCase
and
Continuus Software's Continuus/CM
are two examples of VC/CM products that support a wide range of Unix and PC development environments alike. PVCS, from Intersolv, and Mortice Kern Systems' Source Integrity cov
er the PC domain thoroughly.
The FutureVC/CM system providers are working diligently to deliver on their promise to provide increasingly flexible tools that integrate transparently into the software development process. Because of its inherently heterogeneous nature, the Internet will play an important role in removing barriers to VC/CM solutions by encouraging the development of tools for multisite and cross-platform environments. Indeed, the need to track and manage the rapid evolution of documents that are published on the World Wide Web may prove to be the next mainstream application for VC/CM systems.
The best VC/CM solution for your particular development environment depends on a number of factors: feature set, price, product support, future plans, and supported platforms. Soon -- if not already -- a successful VC/CM system will give your competitors an advantage in the development process. Thus, the time to consider VC/CM is now.
WHER
E TO FIND
Atria Software, Inc.
Natick, MA
Phone: (508) 650-5100
Fax: (508) 650-3573
E-Mail:
info@atria.com
Internet:
http://www.atria.com
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