MNP1163 (Software Construction)

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SDLC and Construction Models
Construction Planning
Construction Measurement

Need, wish, policy, law
User
Requirements
Preparation
Acceptance Test
Operational systems
Acceptance
Test Execution
Systems
Requirements
Global Design
Detail Design
Preparation
Systems Test
Preparation
Integration Test
System Test
Execution
Integration
Test Execution
Component
Test Execution
Implementation

Phase 1 Phase 2 Phase 3

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What is Construction Planning?
Laying out the work plan (i.e. schedule) to design, implement, debug, and unit test the software

 Construction planning major concerns:
 Coders are typically not planners
 Schedules will be difficult to maintain unless a good architecture design is in place
 Many organizations to not collect project data on which to plan future projects
 Many managers consider planning to be a waste of time and therefore don’t encourage it
 Project plans may be limited to the construction plans
 Many organizations and projects do not use systematic cost estimating methods such as models

 Consider reducing development costs by planning to:
 Reduce the size and/or complexity
 Improve the development process
 Use more highly skilled people and build better teams
 Use better tools
 Reduce quality thresholds

 Some actions include
 Use an object-oriented approach
 Use COTS components
 Use an iterative approach
 Provide training to development team
 Automate tedious tasks with tools

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As with building construction, much of the success or failure of the project already determined before construction begins
Upstream activities such as project planning, requirements, architecture, and design are crucial to success
Typical high-risk areas
 Project planning
 Requirements
 Architecture
Preparation is a way to reduce these risks

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The problem being solved via the application must be well defined
Common names for the document containing the problem statement:
 Product Vision
 Vision Statement
 Product Definition
Defines the problem without reference to potential solutions
Helps avoid solving the wrong problem!

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Requirements describe in detail what a system is supposed to do, therefore are invaluable for construction
Explicit requirements:
 Help ensure the user drives system functionality
▪ Rather than the programmer
 Reduce the number of construction debates
 Help minimize changes after development begins
Specifying requirements adequately is a key to project success

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Quality of the architecture determines the conceptual integrity of the system
A proper architecture:
 Gives structure to maintain conceptual integrity
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Provides guidance to programmers
 Partitions work
Architecture-level problems are much more costly to fix than are coding errors
Good architecture can make construction easy
Bad architecture makes construction difficult

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Time budgeted for requirements and architecture work
 10 to 20 percent of manpower
 20 to 30 percent of schedule
If requirements are unstable
 Do not ignore, spend time to fix
 The analyst should fix if a formal project
 Can be fixed by the programmer for informal projects
Use same heuristics for problems with the architecture

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Many software development approaches have been tried over the years
Some examples:
 Functional
 Object-Oriented
 Iterative
 Waterfall
 Agile
 Data-centric
The construction team must follow some approach
Chosen approach must be appropriate for the task at hand

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Programming language choices affect
 Productivity
 Code quality
Programmers more productive using a familiar language
High-level languages provided higher quality and better productivity
Some languages better at expressing programming concepts than others
The ways in which a programmers express themselves are affected by the chosen language

 Questions to answer regarding practices:
 How detailed will the design be?
 What are the coding conventions for names, comments, layout, etc.?
 How will the architecture be enforced?
 Is the project’s use of technology ahead of or behind the power curve, and is this appropriate given the circumstances?
 What is the integration procedure, how often is it done, and who participates?
 Will developers program individually, in pairs, or some combination of this?
 Where and when will builds occur?

Modern programming tools
 Are essential to maintain programmer productivity
 Reduce tedious and redundant tasks
 Must be appropriate for the task at hand
Tools preparation checklist:
 Are all product licenses current?
 Are all products at current, supported revision level?
 Have all programmers received proper training on the tools?
 Does the project have a configuration management tool?
 Does the project have a tool to track change requests?
 Do project team members have sufficient workstations?
 Does the project have sufficient test environments?
 Does the project have sufficient build environments?

 For small development efforts
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 Self managed
 Everyone is a peer
For mid-size development efforts
 Single team
For large development efforts
 Multiple teams

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[IE04] IEEE Computer Society, Guide to the Software
Engineering Body of Knowledge (SWEBOK), IEEE
Computer Society Press, Los Alamitos, CA 20001, June
2004
[RS04] IBM Rational Software, The Rational Unified
Process v2003.06.13, 2004
[RT03]
[SM04] S. McConnell, Code Complete: A Practical
Handbook of Software Construction, Second Edition,
Microsoft Press, 2004.
[WR01] Walker Royce, Software Project Management,
A Unified Framework, Addison-Wesley, Boston, MA,
2001