Product and Project Software Configuration Management (SCM)

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Deployment Models
There are many possible models of deployment that can apply, particularly to products:

  • Local deployment & installation, with a private/independent copy at each installed site
  • Centralized, shared, monolithic, such as a travel service web site, or even something like Google Docs
  • Decentralized and distributed

There are others, too. Each one of these may or may not lend itself well to a particular maintenance and support model:

  • Supporting multiple historical versions
  • Supporting only current version while working on the next one
  • Supporting a product-family of variants of the same set of components

Which model you use depends primarily on upon total number and type of distinct customer-bases and the market (i.e., how likely it is you can expect them to be willing and able to upgrade to new major versions and how much they are willing to pay you to support older ones).

Architecture/SCM/Organization
With the above definition, we can review some of the SCM considerations as to the difference between products and projects. We have discussed how many release engineering issues can be addressed through a balance of architecture, organizational approach, and SCM strategy. Also, using the above definitions, we can consider project SCM needs to be a subset of product SCM.

Product development tends to have release lines - potentially multiple independent projects under development at the same time. As Laura Wingerd discusses in Chapter 7 of her O'Reilly Book (Channeling the Flow of Change):

  • First, at any point in time there is likely to be more than one supported product version available to customers. Ace must be prepared to field customer calls, diagnose problems, and fix critical bugs in all of their currently supported versions.
  • Second, not all development tasks have the same urgency. Some are expected to yield results immediately while others are targeted for distantly future releases.
  • Third, software development is not entirely predictable; some projects go according to plan, others get mired in unforeseen difficulties.

Laura presents release and project branching patterns, and also discusses the Mainline branching model.

The ITIL Service View
Many organizations undertake a variety of internal projects that deliver new or enhanced applications or systems into live usage within the organization. A typical new system or product, delivered as part of a project, might follow a lifecycle and branching model shown below.

From an ITIL viewpoint, the service transition phase (e.g. into live usage) is very important and one of the key measurements is the ongoing documentation and support process that allow the system to be cost effectively maintained in the future. This recognizes the reality that the initial development of most systems is 30% or less of the overall lifetime of a syste

As mentioned above, project teams who are measured only with regard to successful delivery of their project and then leave, for the next project, can leave considerable maintenance problems behind them. We have seen this plenty of times as a significant problem for organizations. And yet this model is still very common.

About the author

Brad Appleton's picture Brad Appleton

Brad Appleton is a software CM/ALM solution architect and lean/agile development champion at a large telecommunications company. Currently he helps projects and teams adopt and apply lean/agile development and CM/ALM practices and tools. He is coauthor of the book Software Configuration Management Patterns, a columnist for the CMCrossroads and AgileConnection communities at Techwell.com,  and a former section editor for The C++ Report. You can read Brad's blog at blog.bradapp.net.

About the author

Steve Berczuk's picture Steve Berczuk

Steve Berczuk is a Principal Engineer and Scrum Master at Fitbit. The author of Software Configuration Management Patterns: Effective Teamwork, Practical Integration, he is a recognized expert in software configuration management and agile software development. Steve is passionate about helping teams work effectively to produce quality software. He has an M.S. in operations research from Stanford University and an S.B. in Electrical Engineering from MIT, and is a certified, practicing ScrumMaster. Contact Steve at steve@berczuk.com or visit berczuk.com and follow his blog at blog.berczuk.com.

About the author

Robert Cowham's picture Robert Cowham

Robert Cowham has long been interested in software configuration management while retaining the attitude of a generalist with experience and skills in many aspects of software development. A regular presenter at conferences, he authored the Agile SCM column within the CM Journal together with Brad Appleton and Steve Berczuk. His day job is as Services Director for Square Mile Systems whose main focus is on skills and techniques for infrastructure configuration management and DCIM (Data Center Infrastructure Management) - applying configuration management principles to hardware documentation and implementation as well as mapping ITIL services to the underlying layers.

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