Systems Development - Systems Implementation

 

Learning Outcomes:

Systems inplementation

• Design and prepare computer-based solutions.
• Explain different types of testing and their uses.
• The types included are unit testing, system testing and acceptance testing.
• Design a simple test plan for functionality of parts of a system.

Systems conversion and maintenance

• Compare different strategies of systems conversion.
• The strategies included are pilot conversion, phased conversion, parallel conversion and direct cutover conversion.
• Explain the need for ongoing maintenance, upgrading and training.

Systems documentation

• Differentiate different types of documentation and their purposes.
• The types included are system documentation, technical documentation and user manuals.

• Document the processes and specifications.
• The examples of documentation are requirement statements, project plans and design plans.

The personnel

• Identify various job titles for different stages of systems development.

 

Systems implementation

 

Sequence of testing: unit test à system test à user acceptance test

• Unit test: Check if each module functions as expected. Done by developer.
• System test: Check if the whole system functions as expected, after integration. Done by developer.
• User acceptance test: Check if the system fulfills user’s requirements. Users are involved.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  2012 2ci. 2014 1ai-iii. 2017 3c.

AL CS2(2003-2012):  2008 9f. 2012 2bc.

Learn more (integration test): AL CS2 2012 2a.

 

Systems conversion and maintenance

 

Systems conversion:

Approaches	Advantages	Disadvantages
Pilot conversion: Implementation of new system in a small section of a company first (pilot area), before promoting to other sections	If problem arises, only a small section of the company affected	Take more time
Phased conversion: The new system is divided into smaller parts (modules) and introduced to the existing system in parts, one at a time	Get used to the system gradually	Take more time
Parallel conversion: Old and new system operate simultaneously for a certain period of time	Failure of new system has lowest impact	Highest cost (more equipment and personnel needed), data inconsistency may arise
Direct cutover conversion: Implementation of new system and discontinuation of old system	Lowest cost	If problem arises, the whole system may be affected

 

System maintenance: 

• correct errors in the system, enhance the functions of the system
• Mode of user training: online teaching, face-to-face, self-study

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  SP 4f. PP 2cii. 2012 2cii.

AL CS2(2003-2012): 2006 3b. 2009 9f. 2012 8e.

 

 

Systems documentation

 

• System documentation: Overview of the system. Usually contains the requirements, design, coding, maintenance, etc. information.
• Technical documentation: Intended for technical maintenance of the system. Contains information such as source code and data flow.
• User manuals: instructions for users on how to use the system.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  2015 2bii.

AL CS2(2003-2012): -

 

Personnel

 

• Project manager: monitor and coordinate the whole project.
• System analyst: define the user requirements and translates them into requirement specification.
• Programmer: write the code according to requirement specification and test the code.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  SP 4d. PP 4e.

AL CS2(2003-2012): 2006 10g.

 

References:

https://www.techbeamers.com/testing-types/

https://www.yourarticlelibrary.com/management/mis-management/top-4-approaches-to-system-conversion-mis-2/70316

http://archives.cpajournal.com/old/09626913.htm

https://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/331_systems_cycle/slc_stages/miniweb/pg22.htm

https://blog.prototypr.io/software-documentation-types-and-best-practices-1726ca595c7f?gi=d201cc280ec7

https://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/331_systems_cycle/roles_project_team/miniweb/pg2.htm

https://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/331_systems_cycle/roles_project_team/miniweb/pg3.htm

https://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/331_systems_cycle/roles_project_team/miniweb/pg5.htm

Systems Development – System Design

 Systems Development – System Design
 

Learning Outcomes:

• Describe the functions of each part of a computer-based system and the related issues.
• This covers the hardware platform, software, inputs, outputs, user interfaces, database structures, data processing, data control, data security and system security.
• Design and appraise an effective interface between the user and the system.
• Different types of human-machine interfaces are compared.
• Know system flowcharts, structure charts, data flow diagrams and data dictionaries to design and document a proposed system.
• Use Gantt Charts for project management.

 

User interfaces

 

• Graphical user interface (GUI)
• Advantages: easy to use, customized interface possible
• Input methods: keyboard, mouse, touch screen
• Screen components: mouse pointer/cursor, icon, menu, button, graphics
• Users: novice

•  Command line interface (CLI)
• Advantages: faster than GUI, keyboard only, in plain text and file format
• Users: experienced user

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  2017 1d.

AL CS2(2003-2012): 2006 10b. 2009 9ac. 2011 10b.

 

System flowcharts

Symbols to be memorized:

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  -

AL CS2(2003-2012): 2008 9e. 2009 9e. 2010 8e. 2012 8f.

 

Structure charts

It gives an overview of the system with its modules and their interaction.

Control information: e.g. Boolean data indicating the validity of the input data

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  SP 4c. 2012 2b.

AL CS2(2003-2012): 2006 3a.

 

Data flow diagrams

 

The purpose of data flow diagram is to map out the data flow of the system.

Tips: classify the given information into data, entity, process and database.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  2013 3c. 2015 4a.

AL CS2(2003-2012): 2004 13c. 2005 13e. 2007 8ab. 2008 9d. 2009 9d. 2010 8ab. 2011 10a. 2012 8c.

 

Gantt Charts

Arrows: to show the dependent relationship i.e. Task 3 depends on the results of Task 1 and Task 2

Critical path: the minimum time to complete the project. In this case: Task 1 à Task 3.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  PP 2ci. 2013 3a. 2015 2a. 2017 1a.

AL CS2(2003-2012): -

Learn more (Critical path): AL CS2: 2003 3. 2004 3a. 2005 4. 2006 13a. 2007 2. 2009 1. 2012 3.

  

References:

https://www.geeksforgeeks.org/difference-between-cli-and-gui/

https://www.smartdraw.com/flowchart/flowchart-symbols.htm

https://www.geeksforgeeks.org/software-engineering-structure-charts/

https://www.smartsheet.com/content/gantt-chart-critical-path

 Systems Development -  System Analysis

 

Learning Outcomes:

• Identify the major task involved in solving a problem.
• List some common methods and activities to gather information for analyzing problems and documenting users’ requirements.
• The common methods and activities are interviews, surveys, questionnaires, observations and document review.
• Know the need for a feasibility study for a proposed solution.
• Examine the pros and cons of alternative proposals.
• Write requirement specifications.

 

Methods to collect user requirements

• Interviews
• Questionnaires
• Observations

 

Feasibility Study

• To find out if the proposed solution should be undertaken or not by analyzing various factors such as practicability, cost etc.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  2012 3d. 2015 2bi.

AL CS2(2003-2012): 2008 9abc. 2011 3a.

 

References:

https://www.tutorialspoint.com/software_engineering/software_requirements.htm

 Systems Development – Basic concepts

 

Learning Outcomes:

• Describe the phases involved in systems development using the Waterfall Model.
• By using suitable case studies, students should experience the processes and activities involved in various phases of systems development.
• Explore the limitations and shortcomings of the Waterfall Model.
• Recognise the benefits and limitations of other approaches.
• Other approaches include Prototyping and Rapid Application Development (RAD).

 

Waterfall Model

 

Steps:

1. System requirement Analysis: Compile user requirements. Document: Requirement documentation.
2. System Design: Establish software and hardware requirements.
3. Implementation: implement the design. Program coding is written.
4. Testing and Integration: Look for any errors in the coding. All units are integrated.
5. Deployment: Deployed to users.
6. Maintenance: Further updates if issues arise.

Each phase is completed before going to the next one.

Documentation is integrated into all the phases.

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  SP 4a. 2013 3b. 2016 1ai-iii.

AL CS2(2003-2012): 2007 1a. 2008 3. 2010 3a,bii,c. 2012 2, 8a.

Learn more: AL CS2 2004 13ab.

  

Limitations and shortcomings of the Waterfall Model

 

The model goes forward only and does not support going backward for revision or improvement.

Requirements defined in the initial phases. Cannot accommodate requirement changes.

Development time is usually longer than other approaches. (no overlapping of different phases)

 

Prototyping

 

After knowing the basic requirement, a prototype of the system is built. Users can try the system and provide feedback to refine the system requirements.

 

Rapid Application Development (RAD)

 

Uses prototyping approach.

Aim at quick development while reducing cost and maintaining quality.

 

Drawback:

• require active user involvement
• RAD not applicable if the system cannot be modularized
• need highly skilled developers for modelling

 

Relevant past paper:

DSE ICT Elect B(SP-2017):  SP 4b. 2014 1aiv. 2016 1aiv.

AL CS2(2003-2012): 2007 1b. 2010 8f. 2012 8b.

 

References:

https://www.tutorialspoint.com/sdlc/sdlc_waterfall_model.htm

http://tryqa.com/what-is-prototype-model-advantages-disadvantages-and-when-to-use-it/

http://cisaexamstudy.com/prototype-rapid-application-development-rad-point-remember/

https://marutitech.com/rapid-application-development/#Disadvantages_Of_Rapid_Application_Development