Requirement Types
Product / process
-  Product requirements 
-  process requirements 
Product Requirements
-  Functional requirements 
-  Non-functional requirements 
Levels of Detail
-  User requirements, targeting
-  customer administrative personnel 
-  contractor administrative personnel 
-  end users 
-  customer engineers 
-  system architects 
 
-  System requirements, targeting
-  end users 
-  customer engineers 
-  system architects 
-  contractor programmers 
 
-  Software design specification, targeting
-  customer engineers (possibly) 
-  system architects 
-  contractor programmers