Software maintenance: Difference between revisions

Software maintenance is one of the activities in software engineering, and is the process of enhancing and optimizing deployed software (software release), as well as remedying defects.

Software maintenance is also one of the phases in the System Development Life Cycle (SDLC), as it applies to software development. The maintenance phase is the phase which comes after deployment of the software into the field.

The software maintenance phase involves changes to the software in order to correct defects and deficiencies found during field usage as well as the addition of new functionality to improve the software's usability and applicability.

Software maintenance involves a number of specific techniques. One technique is static slicing, which is used to identify all the program code that can modify some variable. It is generally useful in refactoring program code and was specifically useful in assuring Y2K compliance.

The software maintenance phase is an explicit part of the waterfall model of the software development process which was developed during the structured programming movement of computer programming. The other major model, the spiral model developed during the object oriented movement of software engineering makes no explicit mention of a maintenance phase. Nevertheless, this activity is notable, considering the fact that two-thirds of a software system's lifetime cost involves maintenance (Page-Jones pg 31).

In a formal software development environment, the developing organization or team will have some mechanisms to document and track defects and deficiencies. Software just like most other products, is typically released with a known set of defects and deficiencies. The software is released with the issues because the development organization decides the utility and value of the software at a particular level of quality outweighs the impact of the known defects and deficiencies.

The known issues are normally documented in a letter of operational considerations or release notes so that the users of the software will be able to work around the known issues and will know when the use of the software would be inappropriate for particular tasks.

With the release of the software, other, undocumented defects and deficiencies will be discovered by the users of the software. As these issues are reported into the development organization, they will be entered into the defect tracking system.

The people involved in the software maintenance phase are expected to work on these known issues, address them, and prepare for a new release of the software, known as a maintenance release, which will address the documented issues.

Historically, for commercial (especially enterprise) software applications, software maintenance was performed by the vendor itself, typically for an annual fee that ranged from 15 to 25 percent of the current license cost of the software application. These software maintenance streams generally constitute a tremendous percentage of the total revenues of a mature commercial software company, and an even higher percent of the profits. For many mature code lines (like Oracle or SAP or Siebel) it is not at all uncommon to see 80 percent -- or more -- of software maintenance fees being "redeployed" into funding development on the current release cycle, rather than being used for actually support and maintenance activities.

All this, in conjunction with enterprise code bases being more stable, has led to the emergence of a new industry: Alternative Maintenance and Support Services (also known as 3rd Party Support & Maintenance). Most impartial observers credit the spotting of this trend, and the founding of the industry, to a former PeopleSoft VP of Global Support & Services named Seth Ravin. PeopleSoft had noticed an increasing number of customers were less than excited about upgrading to the newer releases, and that there was a tremendous demand for "extended support" services that would allow their customers to stay on older releases for long (5+ years) periods of time. As the person who had designed and marketed those services within PeopleSoft, Ravin reasoned -- correctly, it would turn out -- that there would likely be a giant opportunity for a firm to be an *independent* provider of support services, in the enterprise software space.

Ravin left PeopleSoft, continued working on his business concept, and located a former technical support employee of his that had a several person staffing firm doing temporary contracting work in the PeopleSoft universe. Joining the firm as President and infusing it with a new vision, mission, and purpose, Ravin built the company into an alternative support & maintenance powerhouse, although limited to the broader PeopleSoft universe of customers. With the acquisition of PeopleSoft by Oracle, suitors came knocking, and Ravin sold his firm to SAP.

Having proved the demand for a high-quality alternative support & maintenance offering, Ravin decided to combine the best practices of his time running a multi-thousand person operation at PeopleSoft with the entrepeneurial energy of his first support boutique, to redefine enteprise software support. His latest venture, RImini Street, has begun by providing an alternative maintenance offering for Siebel Software licencees.

According to the major market analysts, the trend is likely to head more and more in the direction, for large enterprise software customers, of purchasing continuing support from a different entity than the original license purchase.

• Capability Maturity Model
• Computer software
• Project management
• Software brittleness

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• Paper on Software Maintenance as Part of the Software Life Cycle (from Tufts University)