85 What are the benefits of SCM?
Description
This article is from the Configuration Management Tools FAQ, by Dave Eaton dwe@arde.com with numerous contributions by others.
85 What are the benefits of SCM?
This question arises in several forms. Sometimes it is "what are
the benefits", but often it is "how can I convince management to
use SCM" or "what are/how can I measure the cost savings of
implementing SCM". In many cases, it is an indicator of a company
looking for a "silver bullet". (See the answer to [1.12] "Will a
sophisticated CM system solve my problems?")
First the "bad news": designing and implementing software
configuration management will cost in the short-term, it will not
be a way to realize short-term savings. These costs will be
incurred for design time, tools license fees, equipment costs, user
training, and risks of misuse due to unfamiliarity with a new tool
or platform or process.
However, the "good news" is that in the long run, that is, over the
complete life of a software product, implementing a good SCM
process and system which is used correctly by a properly trained
development staff will save money by improving quality, reducing
problems, and making maintenance and rebuilds of various product
vintages more reliable.
Software development is a complex process. Companies enter into SCM
practices because they want to be able to control and guide that
process as best they can. How much, or how measurable, the cost
savings may be will depend upon how well the company has been
tracking all actual expenses of development, including debugging,
redesign, corrections, etc. over the entire life of the product,
not just to expenses to the first release. If they have no such
metrics tracking, they are unlikely to see a savings they can
recognize (and may even view the implementation of SCM as costing
more).
Some of the specific reasons for implementing SCM which have been
mentioned in this newsgroup over the years include:
* desire to protect their huge investment in software and be able to
reproduce a build with the correct components or continue
development on a project even if those previously working on it
have left the company or become seriously ill
* desire to improve quality and reduce errors caused by building
products with the wrong version or some old code which did not
include a current fix
* simplification of a complicated build and/or release process
* desire to streamline processes and let developers worry about
actual development
* reduction of day-to-day labor, thus allowing an under-staffed or
over-busy team to produce more useful work
* facilitation of moving personnel from one project to another with
little or no loss of productivity since both projects follow the
same process
* elimination of instances in which software needed to investigate
customer-reported problems could not reproduced or rebuilt
* hiring of new team members (particularly leaders and/or managers)
who had good experiences with SCM in prior businesses and
advocated such improvements
* need to perform concurrent development at multiple locations,
particularly if that is already being tried and has gotten out of
hand
* improvement of the faith a Quality Assurance group can have in a
new version of a product for which they are responsible, and
highlighting of areas where a new product version should be
scrutinized during Quality Assurance
Regardless of the reason, it is important to recognize that
deciding to design a good SCM process and implement such a system
is a long-term commitment. The benefits will not be realized
overnight. Sufficient time (sometimes over the course of several
product cycles) is required before the real benefits can begin to
be realized. One error some companies make is to try SCM for a
portion of a project, often never really training the developers to
use it properly or not allowing them the time to become familiar
and comfortable with it, not obtaining adequate hardware to support
the new process, or not configuring their systems properly to
support the new demands put on them. Then the company abandons the
SCM system because of user complaints or, more likely, slippage of
the schedule of that first project (even if the initial schedule
was underestimated).
The essential elements of a successful implementation of SCM
include:
* good planning and design by people experienced in good SCM
techniques
* proper and complete education of those who will be following and
using the system so that they understand not only how to, but why
they must perform certain steps and the benefit to them of doing
so
* sufficient time for the users to become familiar and comfortable
with the system
* advocacy of the new system by "champions" both in the technical
staff and management
* proper equipment and trained support staff to answer questions and
solve problems when they arise (or better still, to tend to the
continual care of the system so problems are avoided)
A side benefit of implementing a good SCM process is that it will
help enable a company to be assessed at a higher SEI Level and/or
obtain ISO 9000 certification. (Note that these are side benefits,
SCM should be approached from the standpoint that it can help you
produce better, more reliable products faster, rather than for the
purpose of attaining an award or certification.)
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