1.軟件開發(fā)最終是由人來執(zhí)行和完成而不是機(jī)器。

# Software development is perbbbbed by human beings. This notion was first popularized by Gerald Weinberg in 1971, with a book entitled The Psychology of Computer Programming (the silver anniversary edition of the book was republished in 1998). McConnell noted that estimating models like COCOMO-II demonstrate the significant cost/effort multipliers associated with having talented, experienced personnel on a project. He also suggests that we can draw three conclusions from this point: (a) the success of companies like Google, Yahoo, and Microsoft is not accidental, and is partially due to their emphasis on hiring talented people; (b) recruiting talented staff members is easily cost-justified; and (c) spending money on employee retention programs is cost-justified.

2.增量開發(fā)是必須的

Incrementalism is essential. Steve distinguishes between “incremental” and “iterative” development; by “incrementalism,” he refers to the idea of developing a little bit at a time, in contrast to the big-bang software development approach.

3.迭代開發(fā)是必須的

Iteration is essential. This is a familiar concept, but Steve warned us to avoid accepting the all-or-nothing extremes of iteration. You don’t have to accept the “keep iterating forever” extreme, nor do you have to accept the “no iterations are allowed” waterfall approach.

4.增加一個缺陷的成本是延長了開發(fā)周期

The cost to increase a defect increases over time, throughout the development life cycle. This is a concept that has been widely accepted for the past 25 years, and McConnell says he has rbbbbidated its truth with data as recent as 2004, including XP/agile projects. I was somewhat surprised by this, because a common argument from the XP/agile enthusiasts is that modern tools have made the old concept irrelevant — i.e., the XP/agile people argue that it doesn’t cost much to fix a requirements defect later in the development process, because modern IDE tools make it easy to redevelop software. McConnell obviously disagrees with this point, and I’ll have to look into it further before I make up my own mind.

5.軟件開發(fā)過程的瀑布模型是重要的內(nèi)核(每一個增量或迭代都是一個小瀑布)

There is an important kernel of truth in the waterfall model of development. McConnell suggests that the primary activities of software development are discovery (of what the requirements really are), invention (of a solution), and construction (i.e., implementation of that invented solution). And he argues that while these activities can overlap and take place somewhat concurrently, there is an intrinsically sequential nature to the activities.

6.精確的軟件估算需要增加整個軟件系統(tǒng)的開發(fā)周期

The accuracy of estimates (about the schedule, effort, and cost) for a project increases over time throughout the development of a software system. There is a great deal of uncertainty in the initial estimates that we create at the beginning of a project. The “cone of uncertainty,” as McConnell calls it, does not narrow by itself, it must be actively managed. As a result, McConnell concludes that iteration must be iterative, project planning must be incremental, and that estimates aren’t meaningful unless they contain a debbbbbbion of their uncertainty.

7.最強(qiáng)大的重用是重用任何可復(fù)用的事物而不僅僅是代碼復(fù)用

The most powerful bbbb of reuse is reuse of everything — not just code. We’ve long known that we should be reusing designs, plans, checklists, role, etc; and McConnell reminds us that we should be reusing processes for developing systems. Indeed, that’s what SEI-CMM level 3 is all about.

8.風(fēng)險管理給軟件開發(fā)過程提供重要的洞察力

Risk management provides important insights into software development. McConnel notes that most projects spend more than 50% of their effort on unplanned work, and that the role of risk management is to reduce unplanned work.

9.不同類型和規(guī)模的軟件需要不同類型的開發(fā)方法論

Different kinds of software calls for different kinds of software development approaches. The “one size fits all” approach to software development bbbbbbologies is just plain silly

10.軟件工程體系和指南是軟件開發(fā)人員的重要資產(chǎn)

The Software Engineering Body of Knowledge (SWEBOK) is an important asset for software developers. SWEBOK has detailed inbbbbation about 10 different areas of software development, including the familiar ones of analysis, design, construction, and testing. McConnell notes that it can be used for curriculum development, career development, certification, interviewing, and building a technical skills inventory.