课程地位学习目标●第1章概述●SOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERING（4）大多数软件是自定的，而不是通过已有构件组装而成的。迄今为止，软件的开发尚未完全摆脱手工的方式。（5）软件成本相当昂贵。IBM360操作系统的研制人员最多时可达1000多人，从1963年到1966年共花了四年时间才完成，总计耗费了5000多人年，以后又进行不断的修改和补充。该系统的整个研制费用为5亿美元，其中近一半花在软件上。（6）软件本身是复杂的。软件比任何其他人类制造的结构更复杂，甚至硬件的复杂性和软件相比也是微不足道的。软件本质上的复杂性是软件产品难以理解，影响软件过程的管理，并使维护过程十分复杂。■产生软件危机的原因：早期的软件开发过程不规范，缺少与程序有关的文档，软件开发的实际的成本和进度往往与预计的相差甚远，软件的质量得不到保证，开发出来的软件常常不能使用户满意。软件的规模越来越大，带来了软件的复杂度的增加，软件的复杂性使软件产品很难理解，而且也会影响软件过程管理，结果可能使软件的开发费用经常超支，完成时间也经常脱期。更为严重的是随着软件规模的增长，可靠性在下降，质量保证也越来越困难，导致软件开发的生产率远远跟不上计算机应用的迅速增长。软件开发时缺少好的方法指导和工具辅助，同时又缺少有关的文档，使得大量已有的软件难以维护。SOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREENGINEERINGSOFTWAREEN