Question

use your own words, don't copy and paste, don't use handwriting, please.

Question 1

Briefly describe the three main types of software maintenance. Why is it sometimes difficult to distinguish between them?

Question 2

What are the strategic options for legacy system evolution? When would you normally replace all or part of a system rather than continue maintenance of the software?

Question 3

Discuss at least four risks that could arise in a given software development, analyse each risk according to its probability and seriousness, and suggest a suitable strategy used to avoid or minimize the impact of each.

Question 4

Some people argue that developers should not be involved in testing their own code but that all testing should be the responsibility of a separate team. As a software consultant, give arguments for and against

testing by the developers themselves.

Answer 1

Answer:

1)

Types of software maintenance: 1. Fault repairs: Coding errors are usually relatively cheap to correct, design errors are more the most expensive to repair because of the expensive system redesign which be necessary 2. Environmental adaptation: This type of maintenance is required when some aspect of the system's environment such as the hardware, the platform operating system, or other support sofware changes the application system must be modified to adapt it to cope with these environmental changes 3. Functionality addition: This type of maintenance is necessary when the system requirements change in response to organizational or business change the scale of the changes required to the software is often much greater than for the other types of maintenance

2)

Legacy system is an operational system that has been designed, implemented and installed in a radically different environment. In critical business systems, it can use many legacy systems. The most appropriate strategic options for evolving these systems are: business process or the business process has changed, leaving the system to be obsolete 2. Leave the system unchanged and continue regular maintenance. This option is chosen when the system is still required but is fairly stable and change requests is rarely happen. 3. Reengineer system to improve maintainability. This is performed when the system maintenance cost exceeds the cost of reengineering the system. 4. Replace all or part of the system with a new system. This is to be chosen when old system can't continue operation or where off-the-shelf systems would allow the new system to be developed at a reasonable cost.

It would normally chosen by the replacement option for all or part of a system rather than continue maintenance of the system In this situation, 1. The hardware platform for the system is being replaced. 2. The system wishes to standardize on some approach to development that is not consistent with the current system. 3. Some major sub-system is being replaced (e.g. a database system) or where the technical quality of the existing system is low and there are no current tools for re-engineering