Phase 3

The Software Requirements Specification
The Software Requirements
Specification
After review of the customer’s System
Spec.
 After educated analysis
 Preliminary design
 A technical, software “approach”
 Results in permission to detail-design
and code

Customer Points-of-Contention
Assumptions, Constraints, Limits
 Function
 Documentation – technical, user, and
training manuals
 Training
 Maintenance / Enhancements
 Requirements Changes
 Status and Reviews

From the customer’s 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
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
Risk Assessment

Technical Risks
◦ hardware / software / interfaces
◦ build vs. buy
◦ team expertise needed

Schedule Risks
◦ budget
◦ calendar
◦ personnel – level of expertise required
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
What is a module?
Storage
Outputs
Processing
Inputs
Simple Block Diagram Form
Arrows, of course, should be labeled
Data Flow Diagram
Temporary Storage
Sink
Data Conversion
Source
DFD Standard Shapes
Arrows, of course, should be labeled
Air Traffic
Control
Radar
Sweep
Data
Conversion
Data
Interpretation
Database
Add
Remove
Disk
Access
Display
Edit
Display
Refresh
Record
UI
Playback
City Simulator
Talking Head
User Interface
Phrasing
MP3s
Prediction
Rules Db
WAVs
Phrase Completion
Presentation
Audio
Construction
Stored Menus
Output
Phrase
Synthesis Engine
Menu PresentationGraphics, Text
User Feedback
Choice
Logging,
Monitoring, &
Annunciation
Build and Release
Edit / Undo/ ReDo
Talker
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
Operator(s)
User IO
Sensors
SensorData
CAPE
SensorConfig
Flight Guidance
Data
Aircraft
Measurement Result s
Result
Database
Cloud Chart - (pre UML) object relationships
Generation 2 Configuration Control Detail
= Internal
Communication
TCP/IP Stack
(HTTP, SNMP,
Telnet)
Socket Input
File System
Serial
Terminal
File Input
Serial Input
Command
Processor
Serial Input