This manuscript focuses the attention on the possibility that some basic programs for solving numerical problems have to be revised. The fundamental case of linear system solution and related concepts is proposed as example of the different ways to approach a problem using object-oriented programming and procedural approaches. The different points of view shows that the traditional approach adopted to deem the conditioning of a system as well as all existing programs to solve linear systems need to be revised. A brief discussion deals with the possibility of parallelizing programs for personal computers and with interaction of parallel computing and object-oriented programming. (c) 2010 Published by Elsevier Ltd.