Software Engineering (2160701)

• When we need to update the software to keep it to the current market, without impacting its functionality, it is called software re-engineering
• It is a process where the design of software is changed and programs are re-written
• Legacy software cannot keep tuning with the latest technology available in the market
• For example, initially UNIX was developed in assembly language. When language C came into existence, UNIX was re-engineered in C, because working in assembly language was difficult.
• Other than this, sometimes programmers notice that few parts of software need more maintenance than others and they also need re-engineering

Re-Engineering Process

• Decide what to re-engineer.
  • Is it whole software or a part of it?
• Perform Reverse Engineering, in order to obtain specifications of existing software
• Restructure Program if required
  • For example, changing function-oriented programs into object-oriented programs and re-structure data as required
• Apply Forward engineering concepts in order to get re-engineered software

Reverse Engineering Process

• Reverse engineering can extract design information from source code
• The abstraction level of a reverse engineering process refers to the sophistication of the design information that can be extracted from source code
• Ideally, the abstraction level should be as high as possible
• The reverse engineering process should be capable of
  • Deriving procedural design representations (a low-level abstraction)
  • Program and data structure information (a somewhat higher level of abstraction)
  • Object models, data flow models (a relatively high level of abstraction)
  • Entity relationship models (a high level of abstraction).
• As the abstraction level increases, information will allow easier understanding of the program
• Interactivity refers to the degree to which the human is “integrated” with automated tools to create an effective reverse engineering process
• In most cases, as the abstraction level increases, interactivity must increase
• The directionality of the reverse engineering process is one-way, all information extracted from the source code is provided to the software engineer