Software verification and validation

摘要

It is tempting just to develop software in the usual way and then try to assure that the finished product is safe. This approach is akin to relying on downstream protection systems-the cost can be exorbitant and the assurance limited. The most practical and effective way to enhance software system safety is to follow a complete safeware program that applies safety enhancing techniques throughout software development and maintenance. Verification testing verifies that requirements for a subsystem have been met. Validation tests a finished device to the original requirements to ensure they have been met. Appropriately applied V and V decreases the cost of software development. Verification and validation can make a significant contribution in making the final product safe and effective. Software changes can be more easily and safely made when the development process is controlled and documented. The template is already in place. Regression testing is easily identified and can reduce the time required to make and test changes. The FDA requires evidence that verification and validation is included in the product development process. The emphasis is on appropriately applied V and V. A software development process that produces, on time, bug free code, meeting all of its requirements, and has intrinsic verification and validation identifying defects as early as possible, is a very cost efficient process, regardless of industry. The earlier a defect is found in the development process, the lower the cost to correct it.