Phase 3

1
Phase 3

• The Software Requirements Specification

2
The Software Requirements Specification

• After review of the customers System Spec.
• After educated analysis
• Preliminary design
• A technical, software approach
• Results in permission to detail-design and code

3
Customer Points-of-Contention

• Assumptions, Constraints, Limits
• Function
• Documentation technical, user, and training
  manuals
• Training
• Maintenance / Enhancements
• Requirements Changes
• Status and Reviews

4
From the customers perspective

• How smart people are going to solve the problem
  that was stated in the System Spec.
• A contract, more or less
• Is it doable?
• Technically
• On time
• Under budget

5
Settles these issues

• Software Architecture
• Object Oriented?
• Structured?
• Database Oriented (Informational Flow)?
• Event Driven
• Major Modules
• to 2 or 3 levels of supervision
• low level utilities if they touch hardware or the
  environment

6
Risk Assessment

• Technical Risks
• hardware / software / interfaces
• build vs. buy
• team expertise needed
• Schedule Risks
• budget
• calendar
• personnel level of expertise required

7
Phase 3

• Write PARTS OF an SRS
• Architectural Drawings
• Main User Screen(s)
• Integration Thread (also a Drawing)
• Change of Scope Form
• Cross Reference Listing

8
What is a module?
Storage
Outputs
Processing
Inputs
Simple Block Diagram Form Arrows, of course,
should be labeled
9
Data Flow Diagram
Temporary Storage
Sink
Data Conversion
Source
DFD Standard Shapes Arrows, of course, should be
labeled
10
Air Traffic Control
Display
Database
Radar
Add
Remove
Edit
Display Refresh
UI
Sweep
Data Conversion
Data Interpretation
Disk Access
Record
Playback
11
City Simulator
12
Talking Head
13
Talker
14
Data Flow Diagram - shows movement, conversion,
and storage of data
This is the "top" drawing of a 6 million,
45-person, 1 million LOC, 4 year project
15
Cloud Chart - (pre UML) object relationships