1.Evolving Software 计算机的计算能力、硬件、系统结构和用户需求在 不断地进步提高，软件从最初的简单的指令集合发 展为复杂的实体。 Case1.美p Here are questions now still 操作系统。 投入开发工 asked: 统每次发行 1.Why does it take so long to get 修正的 software finished? : 这个」 2. Why are development cost so high? 的沉漏 3.Why can't we find all errors before : 的挣扎， giving the software to the customers? 程序设 4.Why do we spend so much time and 中拼命 effort to maintain software? IBM Tr5. Why is it difficult to measure progress? 1 而Bn 人的红示看作 人月神话》(The Myan 伤销不衰Slide 1.4 4/21 1. Evolving Software ⚫ 计算机的计算能力、硬件、系统结构和用户需求在 不断地进步提高，软件从最初的简单的指令集合发 展为复杂的实体。 Here are questions now still asked: 1. Why does it take so long to get software finished? 2. Why are development cost so high? 3. Why can’t we find all errors before giving the software to the customers? 4. Why do we spend so much time and effort to maintain software? 5. Why is it difficult to measure progress?