Principles of Software Engineering
1) Describe each law in your own words. Illustrate with a practical example.
Glass’ law
Requirement deficiencies are the prime source of project failures. (Endre & Rombach, 2003)
Requirements are the basic Phase which lead to the development of a project. In fact, it is the first step for any project The main problem in a project failure is the lack of requirements.
The common requirement error is due to human (i.e lack of Communication between customer and the analyst), software, etc.
Example: Denver International Airport Reason: Underestimation of complexity, Complex architecture, Changes in requirements, Underestimation of schedule and budget, Dismissal of advice from experts, Failure to build in backup or recovery process to handle situations in which part of the system failed.
Boehm’s first law
Errors are most frequent during the requirements and design activities and are the more expensive the later they are removed. (Endre & Rombach, 2003)
Errors occurred at the later stages of the project are very expensive in terms of both time and cost because every project goes through software development life cycle, and any changes made in the later stages would result in re-consideration for all the previous stages and this would cause lot of delay in project and even cost of the project increases Example: According to a study done at TRW in 1974, the percentage of errors in design stage was 64 where as coding errors account to 36 percent and also 54 percent of errors were not found earlier than acceptance testing. Design errors took twice as much time to diagnose and correct than coding errors. The cost of fixing a problem at later stages will be much more when compared to that of fixing problems at earlier stages.
Boehm’s second law
Prototyping (significantly) reduces requirement and design errors, especially for user interfaces. (Endre & Rombach, 2003)
Example: Software applications that are relatively easy to
Glass’ law
Requirement deficiencies are the prime source of project failures. (Endre & Rombach, 2003)
Requirements are the basic Phase which lead to the development of a project. In fact, it is the first step for any project The main problem in a project failure is the lack of requirements.
The common requirement error is due to human (i.e lack of Communication between customer and the analyst), software, etc.
Example: Denver International Airport Reason: Underestimation of complexity, Complex architecture, Changes in requirements, Underestimation of schedule and budget, Dismissal of advice from experts, Failure to build in backup or recovery process to handle situations in which part of the system failed.
Boehm’s first law
Errors are most frequent during the requirements and design activities and are the more expensive the later they are removed. (Endre & Rombach, 2003)
Errors occurred at the later stages of the project are very expensive in terms of both time and cost because every project goes through software development life cycle, and any changes made in the later stages would result in re-consideration for all the previous stages and this would cause lot of delay in project and even cost of the project increases Example: According to a study done at TRW in 1974, the percentage of errors in design stage was 64 where as coding errors account to 36 percent and also 54 percent of errors were not found earlier than acceptance testing. Design errors took twice as much time to diagnose and correct than coding errors. The cost of fixing a problem at later stages will be much more when compared to that of fixing problems at earlier stages.
Boehm’s second law
Prototyping (significantly) reduces requirement and design errors, especially for user interfaces. (Endre & Rombach, 2003)
Example: Software applications that are relatively easy to