软件作为一种高智力的创造活动 ,与一般制造业有很大区别 ,其重点在设计过程。由于软件开发从立项开始直至交付、上市的整个过程受人为因素影响很大 ,再加上市场及开发实际情况的变化 ,最终产品往往同最初的计划相差很大 ,发生变更是不可避免的。这种变更可能来自顾客的要求 , As a high intelligence creation activity, software is very different from the general manufacturing industry, and its emphasis is on the design process. Since the entire process of software development from the start of the project to the delivery and listing has been greatly affected by human factors, coupled with changes in the actual situation of the market and development, the final product is often very different from the original plan, and changes are inevitable. This change may come from the customer’s request.