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Q&A- System Development

Explain the differences between parallel running and direct changeover as ways of implementing the new system.

Direct changeover – new system replaces existing system immediately/overnight

 Parallel running – new system runs alongside/together with existing system

Parallel running – there is always the old system to fall back on in the event of the new system failing/information is not lost/always a second copy

Direct changeover – if things go wrong lose all data/old system is not available

Direct changeover – training is more difficult to organise

Parallel running – training can be gradual Parallel running is more expensive to implement than direct changeover....

Direct changeover is a quicker method of implementation than parallel running

Direct Changeover: The old system is stopped completely, and the new system is started. All of the data that used to be input into the old system, now goes into the new one.

 Parallel Running: The new system is started, but the old system is kept running in parallel (side-by-side) for a while. All of the data that is input into the old system, is also input into the new one. Eventually, the old system will be stopped, but only when the new system has been proven to work.

What situations are likely to call for the use of Direct Changed Over?

  • where the new system is completely different from the old one
  • if there has been extensive testing of the system and the system analyst has confidence in its functionality
  • If the system is not critical

State a stage in system development where each of the following activities are carried out    (KCSE 2018)

(a) Identifying technologies that may be used in a proposed system

  • System Analysis/Information gathering/Problem recognition

(b) Identifying the shortcomings of the old system

  • Problem definition

(c) Prepares the software migration plan

  • Implementation stage

Describe the problem recognition and definition stage of system development

  • problem recognition involves the system analyst identifying and accepting the existence of a problem in the current system
  • problem definition involves the analyst studying the system to understand its operations and shortcomings

There are four change-over methods used in the implementation stage of the system development life cycle (SDLC): direct change-over, phased, parallel and pilot.

Direct Change-Over

  • A date is chosen for the shutdown of the old system, then at that time, the old system
    is turned off and the new system is implemented

Phased

  • Parts of the new system are implemented in stages or for a period of time, both the old and the new system are running together until all parts of the system are implemented.

The introduction of a new system involves evaluation and maintenance once the system is
implemented.
Describe the evaluation and maintenance stage of the systems development life cycle (SDLC)
and provide one example of an activity undertaken in this stage.

  • Continually monitoring, evaluating and updating the system once it is operational. Activities include rectifying bugs, requesting changes, updating aspects, finding errors, maintaining code etc.

A company has decided to deliver its products online to international customers. It has employed you as a project manager to determine whether this is a viable business decision. You choose to conduct a feasibility study. Outline the purpose of a feasibility study using two components associated with this process.

  • It covers many aspects that will be used to decide whether to go ahead with the project or not.
  • The main components are technical, operational, economic, legal and scheduling.

Describe one task that is commonly undertaken during the first phase of system development life cycle

  • The preparation of a system proposal which lists the problem definition, objectives of the study, terms of reference of study, constraints, and expected benefits of the new system, in light of the user requirements

Outline one advantage and one disadvantage of interviews and questionnaires as data gathering techniques.
 

Interviews

Advantages

  • can gather specific information and additional information
  • high response rate to questions
  • The question can be rephrased to seek more clarification
  • it is possible to win the confidence of the interviewee and get honest answers

Disadvantages

  • time consuming
  • responses to interview questions are subjective.
  • the interviewee may not open up on some sensitive issues
  •  

Questionnaire

Advantages

  • easy to administer
  • can be anonymous.

Disadvantages

  • fixed (inflexible) design
  • potential differences in understanding and interpretation.

Describe the purpose of a data dictionary, using an address book database as an example.

  • when designing a database a data dictionary provides the description and purpose of the fields/attributes of the database table(s). For example the field name (i.e. “phone number”), the data type (text); the size of the field (10) etc.

Give two characteristics of each of the system development methodologies listed below.

(a) Linear/Cascade/Waterfall

(b) Iterative Methodology

(a) Linear/Cascade/Waterfall

  • a project is divided into stages or phases
  • it is sequential, each stage needs to be completed before moving on
  • clear goals are set for each stage

(b) Iterative Methodology

  • effective in producing a working prototype in a short period of time
  •  involves extensive user input and testing
  • based on build – test – evaluate process, the philosophy is re-build until users are completely satisfied
  • features user input throughout the process which enables ongoing, responsive changes to be made to the design.

At which stage of the system development life cycle does the changeover to a new system take place?

  • Implementation

What characterises a phased implementation approach?

  • Phased means that only one part of the system is implemented at a time

Give one reason why a phased implementation would be the best approach to follow in this case.

  • This approach causes minimum disruption

 Complete the data dictionary below for the Student entity.

  • StudentID: String
  • FirstName: Required 1
  • Year: 2 1
  • Email: Email address containing @ sign 1
  • AccountBalance: Real

State four tasks performed at the analysis stage in systems analysis.

  • understand the current system
  • produce data flow diagrams/system flowchart
  • identify user/client requirements/objectives
  • interpret user/client requirements/objectives
  • agree requirements/objectives with the user/client
  • collect data from the current system
  • fact finding (e.g. questionnaires, interviewing, etc.)
  • problem identification

State advantages and disadvantages of the following system implementation strategies

Phased:
Advantages:

  • only a small part of the operation affected if new system fails
  •  no need to pay for two sets of wages

Disadvantages:

  •  time consuming (each part needs testing fully before expanding system)

Pilot:
Advantages:

  • if new system fails, only that part will be affected
  • possible to gradually train staff on pilot before whole system changes over

Disadvantages:

  •  time consuming (waiting to see how pilot works before rolling out to rest of the organisation)

Direct:
Advantages:

  •  less likely to malfunction since fully tested
  • immediate benefits/less time wasted
  •  reduced costs (only one system so no need to duplicate staff)

Disadvantages:

  • disastrous if the new systems does fail

Parallel:
Advantages:

  •  if new system goes down, there is a backup system in place
  • possible to gradually train staff/staff have time to get used to the new system

 

 

 

State the contents of a feasibility study report

  • Recommendation on whether to continue or abandon the project
  • Methods used to collect data
  • benefits and limitations expected
  • the technology required to develop and maintain the project
  • Installation and running cost
  • Time limit

Explain why the organization's management and the analyst need to work together to define the problem accurately during system development

  • College authorities are the experts in the problem
  • A system Analyst is an expert with computers
  • The two need to pool resources to come up with a clear definition
  • Agree on the outcomes so that when the system is , there are a set of criteria to judge it by

A company has decided to use a computer for stock control. Describe the process of systems development from the time the decision was made to proceed with computerisation until final testing.

specify output requirements
design documents/screen displays
data for input/storage
form design
storage devices
file structures/access/design
data security/back up files
systems flowchart etc.
implementation i.e. pilot/intermediate/parallel running
testing strategy
training
hardware/software
programming/algorithms
validation
user manual
technical documentation
entering data into system

State the reasons for system review and maintenance

  • user changes his mind
  • new government legalisation/company policy company changes
  • changes in hardware
  • changes in software/upgrades/new versions
  • improved operating efficiency/ease of use

Name three of the stages in the system life cycle

fact finding
feasibility study
analysis
design
testing
documentation
implementation/changeover/installation
evaluation
maintenance