2008 Volume 38 Issue 2 Pages 174-181
Things present are judged by things past. Any person that would know what shall be must consider what has been. The quality assurance activities on our computer software products must learn many things from that of experienced hardware production. Especially any lack of understanding on the dispersion and the control chart may cause much chance loss for the improvement and maintenance of the software production process. And the drawing a sharp line between the variation within subgroup and the variation between subgroup is very important. In this way the reliable software production process can create new things by reviewing various old things.