Week 12 February 6, 2009

1.    What was the most difficult assessment item you completed in COIS20025 this term

Ans: – Both are not difficult for me. According to me, assessment item 2 was  little bit complex because it needs to change the Process model into correct data model and so much search was needed to get data related to comparison of data model and process model because both are modelling technique with only the difference of diagrammatical representation.

2.   What was difficult about it and how would you suggest it could be improved?

Ans: – the difficult about it was that it needs so much search and depth understanding of both models. Data model can be improved only by clear understanding of identifying all attributes, entity and referenced data.

3.   Name three (3) things you learnt this term in COIS20025.

Ans: – in this term of COIS20025 course; I have learnt many things and get experience in designing phase of SDLC. The three things are:

(a)  I have learnt about system development life cycle.

(b) Learnt about social and ethical issues.

(c)  Learnt about designing process model of information system and data model used to implement database.

4.   What career are you working towards?

Ans: – I am working toward the career in system analysis or database administrator. In both roles, this course is helpful to create both information system and database system.

5.   How will you be able to use the knowledge and skills learnt in this course in your future career?

Ans:- I have gotten too much knowledge and skill like how to develop a system, how to enhance ,repair or modify the existing system by using which of maintenance type according to the need, what are the social ethical issues should kept in mind while developing system and what development cycle must used during developing information system. These are helpful in future career of system analysis or database administrator.

 

Week 10 February 6, 2009

Que:

Week 10

On pages 512 – 514 the textbook identifies and discusses four types of maintenance tasks. Post an entry to your blog that gives one example of each type of maintenance task that might be needed once BHSSRS (the system you have modelled and designed the data for in assignments 1 and 2) is in operation.

Ans:-

There are four types of maintenance tasks.

1. Corrective maintenance

2. Adaptive maintenance

3. Perfective maintenance

4. Preventive Maintenance

In this entry of blog, there is a discussion of each type of maintenance task that might be needed once BHSSRS is in operation.

1.  Corrective maintenance: – corrective maintenance refers to change made to repair defects in the design, coding or implementation without adding any functionality. If this maintenance task is used in Bowen High School Student Record System then there is a need to repair only. If we use this maintenance task in existing BHSSRS then there is a need to change or repair programs or repair or need to change format of stored data. Suppose there is problem in enrolment system of students. Then there is a need to repair the programming or design errors without adding extra functionality which cost less and more urgent than other.

2.  Adaptive maintenance: – it is technique to modify the system to environmental changes. These changes are being done because of change in business need or migrate to different operating environment. This adaptive maintenance in BHSSRS is used only when there is a change in business rules or migrate it to different operating environment. If this is slow system or there is a change in rules of BHSSRS then this type of maintenance will be opted by developer. But it is not needed by school because no business rules have been changed and no need to change its operating system.

3.  Perfective maintenance: - this maintenance will be opted if there is need to make extra addition, improves processing performance but not necessarily required. It is actually new development not really maintenance. Perfective maintenance is not so useful for Bowen High School because there is a need to change whole system rather minor development. But after development of Bowen high school student record system, if there is need to add something new features then it will be the best approach.

4.  Preventive maintenance: - it involves change made to a system to reduce the chance of future system failure. It is good approach if it implemented to BHSSRS to reduce or minimise future failure.

 

Adaptive , perfective, and preventive maintenance activities can lead to corrective maintenance activities if not carefully designed and implemented.

Week 9 February 5, 2009

Ans:

System changeover is a process of putting the new system information only and retires the old system.

There are four possible approaches to changing from one information system to another. There are several implications of using each of these approaches to change from the existing system to the new BHSSRS and many benefits and problems associated with each approach. These are given below:

1. Direct Cutover: – using this approach, we put new system in the organisation and retire the old system immediately. But this approach is more risky because regardless of carefulness during testing/training, there may be some errors caused when it goes into operations. There is also a difficulty during the detection of errors. It is another disadvantage of this approach that if we are using a new system, then the old system will not be available. If any problem arises then detection of error is difficult because we can’t compare and verify current output with output of old system. But if it is maintained with knowledge based data then it will be best approach to develop this software package. Timing matter should also be considered if we need direct cutover approach because this system may operate monthly sycle. If student pay fees monthly, submitted assignment monthly and may be in yearly cycle when released Student Semester Report. So, information system of Bowen high School should converted at the beginning of the month or year. If it is implemented and operated at the middle of the cycle, then there may be situation arise when there is a need of information of both new operation BHSSRS and old system which is unavailable.

2. Parallel Operation: – it needs to operate both old and new system simultaneously. If this approach is implemented in developing BHSSRS,then there will be lower risk then previous approach because it is easy to compare or verify the output of both system and check it is working correctly or not ,if the new one does not operate properly then, we can opt old system as backup until appropriate maintenance. And when student administration department/section, students and teachers are satisfied with new system then old system can be terminated. But Bowen High School has tightening budget so this parallel operation approach is difficult to use both system can operate simultaneously only when there are more extra staff to operate any system and may need arise to hire extra temporary employee in Student Administration section to operate both system which is expensive. Another disadvantage of this approach is, if new system of Bowen High School is incompatible with existing operating system then it is difficult to operate both because it will cost high.

Pilot Operation: – pilot changeover method is better than other approach .it is combination of parallel and direct cutover method. During this changeover method, new system administration inforamtion system will be installed in one location called pilot site where groups or user will used new system and old system will be operated in rest of the school. Of the new system at the pilot site proves successfully then it will be converted into new system by direct cutover. So there is less chance of system failure because if any problem arises during the operation of new system then we can easily compare with existing system and verify or fix the problem easily. The problem in this is same as parallel that it needs both extra staff and extra time for testing which is more expensive.

Phased operation:- the phased operation changeover method allows to implemented new system in modules. Suppose if student administrative information system is divided into subsystem such as enrolment subsystem, class subject subsystem, timetabling subsystem, student semester report subsystem, hold subsystem and we might install only one subsystem, and then user will operate one module at a time. It will be less expensive. If it does not operate successfully, it could not affect another module. But there is risk of errors and failure. And sometimes it is difficult to separate module logically, if we separate it successfully, then it will be more expensive than pilot operation approach.