1. Construction Planning and Prerequisite
Measure Twice, Cut Once
Chapter 3

2. Importance of Prerequisite
Earlier parts of projects are “Prerequisite”.
Projects run best if appropriate preparation activities are done before construction
Removing an error by the beginning of construction allows rework to be done 10 to 100 times less expensively

5. Problem-Definition Prerequisite
Is clear statement of the problem
Does Not indicate to any possible solution
One or two pages and sounds like problem
Should be in user language and described from user’s point of view

6. Good Example:
“We can’t keep up with orders for Giant”
Bad Example
“We need to optimize our automated data-entry system to keep up with orders for the Giant“

7. Requirements Prerequisite
Contains what a software system is supposed to do
The first step toward a solution
Helps user derive system’s functionalities
User can review and agree on requirements
Keep programmer of guessing what the user wants

8. Architecture Prerequisite
High level part of software design
Known as “system architecture” or “high-level design” or “top-level design”
Good architecture makes construction easy
Architecture changes are expensive to make during construction or later

9. Typical architecture components
Program Organization
Defining major building blocks
Might be class, group of classes (subsystem)
Includes communication rules with other blocks,
Major Classes
Responsibilities of major classes and interaction with other classes
Data Design
High level of file and table design
Specify if single or multiple database to be used
Business Rules
Must be mentioned and describe the impact of the rules on system design

10. Typical architecture components .. continue
User Interface Design
Usually specified at requirements time
Major elements of web page format, GUIs, command line interface ..
Recourse Management
How managing resources such as database connections, threads, memory ..
Security
High level and code level security
Handling un-trusted data (such as user data, cookies, configuration data), encryption, detail in error messages.
Protecting secret data in memory

11. Typical architecture components .. continue
Scalability
The ability of a system to grow to meet future demands
Plan to handle growth of users, servers, number and size of database records, transaction volume
Interoperability
How data or resources will be shared with other software or hardware