Original Date: 02/01/1991
Revision Date: 01/18/2007
Information : Software Development and Testing
A Total Quality Management (TQM) Focus team devoted to software issues initiated a series of improvements in Litton Guidance and Control Systems Division’s (GCSD’s) Software Development and Software Test processes. The Focus team was drawn from all Software Development groups and from Software Quality Assurance. One key task accomplished by this team was revision of all procedures contained in Litton GCSD’s Software Manual. The content of each procedure was established by consensus over a nine-month period. This team is now developing Software Quality and Software Development Plan templates for typical project scenarios. The intent is to develop pre-approved templates for use in reducing the cost and required effort to develop and negotiate similar Software Development and Software Test Plans from project to project.
Another change in the software development and test processes involved the Software Quality History Log maintained by Software Quality Assurance personnel. Internal peer audits were initially instituted to help ensure the Software History Log was well maintained and current. However, this change served as a prelude to a more significant one in that in the software development process, high level software tests are now written by the Software Quality Assurance person assigned to audit the Software Quality History Log.
Experience with the first effort using this process suggested that test procedures are better written with test, and not design, in mind. A design engineer tends to test his design, while the test engineer, having no personal involvement in the design, tends to test to actual requirements. Litton GCSD claims that this initial effort has resulted in a 15% savings in the cost of developing software tests because of more productive use of both test and design personnel.
The “peer walk-through” methodology was also modified. Circulating codes for review prior to a walk-through, holding the walk-through, and documenting and tracking action items tended to be effective for software modules with only a small number of code lines. This problem was addressed by another Engineering Focus team which concluded that peer walk-throughs were of marginal value. The suggested change assigns each participant in the peer walk-through responsibility for only one specific aspect of the review. At the review meeting, each participant now submits a signed certification that the code meets all requirements and specifications associated with his assigned responsibility. Litton GCSD states that this change, which was adopted, has decreased the workload on each reviewer, and with the certification, has increased the energy with which reviewers now participate, resulting in peer walk-throughs being viewed as a value-added process.
Litton GCSD is also engaged in innovative work in software measurements. On past programs, software error detection tended to peak during software integration, following the error curve for complex software developments postulated by Putnam. Litton GCSD believes it may be possible to develop algorithms which would allow prediction of the cost and schedule required to achieve a desired level of quality using history from previous software development efforts. This effort is the subject of a Masters Degree project by five members of Litton GCSD’s Software Quality Assurance staff.
For more information see the
Point of Contact for this survey.