Design#

When a program is being tested, it is too late to make design changes ~TAO of Programming

Links#

• Unix Philosophy
• Twelve Factor Application

See also#

• List of Software Development Philosophies
• Martin Fowler
• Mythical Man Month

Unix Design Philosophy#

• Separate Mechanism from Policy
• Policy answers the question "what are we going to do?"
• Mechanism answers the question "how are we going to do it?"
• Bottom up design
• Mechanism before Policy

Invertible architecture#

• Application is composed of one or more policies
• Policies are composed of one or more mechanisms
• Mechanisms can be easily swapped
  • Policy remains unchanged

Model View Controller#

• Extends the Observer Pattern
• Makes consideration for modifying data

Application Load Balancing (ALB)#

• Uses additional technology layer
• Not to be confused with a DNS load balancer
• Cannot have Web Application Firewall (WAF) without Load Balancing