Editing Computer program (section)

===Waterfall model===
The [[waterfall model]] is an implementation of a ''systems development process''.<ref name="se-ch1-8">{{cite book
  | last = Schach
  | first = Stephen R.
  | title = Software Engineering
  | publisher = Aksen Associates Incorporated Publishers
  | year = 1990
  | page = 8
  | isbn = 0-256-08515-3
}}</ref> As the ''waterfall'' label implies, the basic phases overlap each other:<ref name="pis-ch12-p517">{{cite book
  | last = Stair
  | first = Ralph M.
  | title = Principles of Information Systems, Sixth Edition
  | publisher = Thomson
  | year = 2003
  | page = 517
  | isbn = 0-619-06489-7
}}</ref>
# The ''investigation phase'' is to understand the underlying problem.
# The ''analysis phase'' is to understand the possible solutions.
# The ''design phase'' is to [[Software design|plan]] the best solution.
# The ''implementation phase'' is to program the best solution.
# The ''maintenance phase'' lasts throughout the life of the system. Changes to the system after it is deployed may be necessary.<ref name="se-ch11-345">{{cite book
  | last = Schach
  | first = Stephen R.
  | title = Software Engineering
  | publisher = Aksen Associates Incorporated Publishers
  | year = 1990
  | page = 345
  | isbn = 0-256-08515-3
}}</ref> Faults may exist, including specification faults, design faults, or coding faults. Improvements may be necessary. Adaption may be necessary to react to a changing environment.