CM: The Nerve of Your Life Cycle Management


Similarly, we don't baseline all of our data, but we do have the capability of creating a checkpoint file which captures the exact state of the repository at a given point in time in just a few megabytes. That's good, because if we want to prove that our data has not been tampered with after the fact, we can view our repository from the perspective of a given checkpoint file. But that's what it is. It's a snapshot in time. We don't switch back and forth between checkpoint contexts and do queries between checkpoints. They're different from baselines. Perhaps a baseline is to CM as a checkpoint is to data, but having the checkpoint capability does take away the reasons that we might otherwise have for applying CM to all of our data.

Configuration and Data Management
We will now return to our original discussion. There are objects that we perhaps will agree don't need configuration management. These objects might include problem reports, build records, change records, activities, and users. I'm sure I could make a case for CM for some of these things, but I won't until I really see a need. If the CIA needs to track revisions of a user so that it knows what permissions and brain implants the user had on a specific date, we'll adapt our user management to permit that. In fact, you might find that version control of users is not so far out when you start to consider staff relationships. But it's a capability that has to be addressed as needed, and in such a way as to keep things as simple as possible.

Application life-cycle management depends not only on CM capabilities, but other generic data as well. At times, it's hard to separate CM from data management. A new revision of a requirement is really just another requirement record that is tied to its predecessor requirement revision record, isn't it? We're back to our yes and no response. Databases generally don't understand concepts like revisions, history and baselines. Revisions of a requirement form a history. They can be collected into baselines. Though it's ultimately the database that represents these relationships, it's CM that understands them. Without the CM, we need a data interpreter.

Advanced DM tools (or hybrid databases, as I might refer to them) will let us express all sorts of data, data dependencies and data relationships. Good CM tools will let us look at data from a specific configuration viewpoint. It will let us specify revisions and branches, and so forth. An integrated CM and DM tool will do so much more. Try storing the include relationships of each file for each revision. Any database will let you do that with the appropriate schema. It's just that when you get a half-million file revisions that you realize that the 50 million include relationships are causing a bit of a performance issue.

Take an integrated CM/DM tool that will automatically difference and restore the include list only whenever it changes. Or take an integrated CM/DM tool that will let you compute the affected source files, not for a specific configuration, but for an arbitrary rule-based configuration that changes over time, even when the include lists which dictate the affects relationship doesn't. This integrated entity understands data and CM.

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