Box structure development is not allowed, it is strictly forbidden to reproduce this column This paper has been made from the software engineering expert network www.21cmm.com. Do not reprint without CBS license, thank you for the cooperation "clean room software specification" describes the system Or two functional views of the program. The first is based on an external behavior (black box), the second state-based state machine (state box). The third perspective is described below - a process or algorithm for implementing a status cartridge and demonstrating a particular external behavior (bright box). The auto-down cycle process must make many design decisions. Through this process, the highest level specification of a complex system is transformed into a code body executed on a computer. The box structure method itself does not make a design decision, but the designer is best considering the entire solution. Solutions include all possible implementations - good, bad, poor, fast and slow solutions, easy to correct and maintain, and difficult to maintain, in one case, in one case, but in another Inaso in the case. So the design decision must consider many frequent conflicts. The high-level black box of behavior is described in a specific demand. There is a pair of relationships between the black box and the state box that reflects the behavior. Here there is also a control status information and data information, and there is often a balance between the two. The smallest control status information may cause performance to be unacceptable, eventually resulting in excessive control information. Similarly, there is a balance between the data stored in the table and the value recalculated on demand. The figure below shows a general solution space, which has a unique black box and several possible state boxes, all of which reflect the behavior of the black box. The cassette structure emphasizes this relationship and reminds designers consider those status boxes related to all features designed. Commending specific status boxes (temporarily) excludes many solutions, but not fully determines the bright box option. There is a pair of relationships between a given state box and many of the bright boxes or algorithms that achieve their functions. Similarly, the choice of the mandatory box will limit but not fully determine the final solution. As described herein, the bright box is always defined as a structured program, which may contain a more underlying black box. If given a clear specification that must meet, each black box in the bright box is the only one. This step-by-step process produces a layered structure diagram of a box structure, as shown below. It is important to keep the correction and evaluation during a design process. Designers should not ignore this fact: he wants to consider the entire solution, and select a path from the highest layer black box to the final solution. Better thinking winter winter appears during the design, few exceptions. The first program is almost impossible to be the best, so it is better to find a difference in the design of a difference design, it is better to find a better method. The process of design can be seen as analysis and selection - to make a range of options, estimate, and may reconsider. The control of the selection depends to a large extent. If there is a production line structure, you will use some features, status, and algorithms in the solution. The designer should also take the reuse of the existing structure rather than re-developing the cassette structure itself does not create structure and make design decisions; these tasks should be done by the designer. However, after understanding the entire solution space, the cassette structure is conducive to improving the quality of the structure, finding other alternative structures after analysis and decision.
