|5.4 Category of Methods "Program Verification" (PVER)|
PVER - Programmverifikation
These methods are presented in the following individual descriptions. In order to make it easier to distinguish between the individual methods these methods are first compared with each other.Classical Program Verification this is done only after completing the program. Within Verification during Development (Program Verification) every refinement step is proved immediately. within the Formal Transformation (Program) a specification is transformed into a target specification is transformed into a program by means of transformation rules. Prior to the transformation the correctness of the transformation rules is already mathematically proven.
The Classical Program Verification the program may already be tested before it is proved. Within this method often it is difficult to localize or to correct an error especially in those cases when it is not possible to furnish the proof of correctness or when it turns out that it is not a correct program. Within the Formal Transformation (Program) and the Verification during Development (Program Verification) every development step is proved immediately. Therefore, an error is easy to correct, but it may be difficult to optimize the program. The proof tasks within the Formal Transformation (Program) are the most insubstantial because the proofs generally have been proved already. On the other hand, it is difficult to provide a complete set of transformation rules necessary for the implementation.
|Classical Program Verification||Verification during Development (Program Verification)||Formal Transformation (Program)|
|Great effort for the proof||Great effort for the proof||Comparatively small effort for the proof, because the rules have already been proven but the development may require a long time|
|Set of rules generally sufficient for limited programming constructs||Set of rules generally sufficient for limited programming constructs||Set of rules generally only sufficient for limited problems|
|Error detection possibly difficult; possibly work has to be started again||Error detection simple, because every design step is proved immediately; possibly only the last step has to be modified||In practice errors not possible, because only correct transformations are performed|
|Later verification possible||Later verification not possible||Later verification not possible|
|Testing the program is possible prior to proof||Testing the program is not possible until the proof is nearly completed||Program is not available until the last transformation|
188.8.131.52 Classical Program Verification
|GDPA Online Last Updated 01.Jan.2002 Updated by Webmaster Last Revised 01.Jan.2002 Revised by Webmaster|