Waterfall Model

Waterfall Model:

Click here to view on YouYube

  • It was the first model introduced.
  • It is also known as linear sequential life cycle model.
  • It is very simple and understand to use.
  • It is basic of all the process development models.
  • It is a theoretical model, not to use practically.
  • It is called Waterfall because stages goes top to bottom like a natural waterfall.
  • When one stage gets completed then only move to next stage.
  • Not supposed to come back to previous stage.
  • This is considered conventional or classical software life cycle model.

Following is the illustration of Waterfall model:

Advantages of Waterfall Model:

  • Simple and easy to understand and use.
  • Phases do not overlap.
  • Phases are executed one at a time.
  • Each phase has specific output and a review process, which makes it easy to manage.
  • Best for small projects where requirements are very well understood.

Disadvantages of Waterfall model:

  • When model in execution it is very difficult to go back and make changes in previous stage.
  • Risk is very high.
  • Not suitable for complex and object oriented projects.
  • Not suitable for large projects.
  • Not suitable for when requirements are not understood, or requirements are not fixed.

When to use Waterfall model:

  • When the requirements are fixed, understood.
  • Product is understood.
  • Technology is understood.
  • When the project is short.
  • It is costly if project requirements are frequently changing.

Why does the Waterfall model sometimes fail?

Real projects rarely follows the sequential approach which Waterfall model follows. This creates problem when error occured and we can't go back to the previous stage to correct it.

More topics from Software Engineering to read
Software Engineering

EasyExamNotes.com covered following topics in Software Engineering.

Python Programming ↓ 👆
Java Programming ↓ 👆
JAVA EasyExamNotes.com covered following topics in these notes.
JAVA Programs
Principles of Programming Languages ↓ 👆
Principles of Programming Languages
EasyExamNotes.com covered following topics in these notes.

Previous years solved papers:
A list of Video lectures References:
  1. Sebesta,”Concept of programming Language”, Pearson Edu 
  2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
  3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
  4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

    Computer Organization and Architecture ↓ 👆

    Computer Organization and Architecture 

    EasyExamNotes.com covered following topics in these notes.

    1. Structure of desktop computers
    2. Logic gates
    3. Register organization
    4. Bus structure
    5. Addressing modes
    6. Register transfer language
    7. Direct mapping numericals
    8. Register in Assembly Language Programming
    9. Arrays in Assembly Language Programming


    1. William stalling ,“Computer Architecture and Organization” PHI
    2. Morris Mano , “Computer System Organization ”PHI

    Computer Network ↓ 👆
    Computer Network

    EasyExamNotes.com covered following topics in these notes.
    1. Data Link Layer
    2. Framing
    3. Byte count framing method
    4. Flag bytes with byte stuffing framing method
    5. Flag bits with bit stuffing framing method
    6. Physical layer coding violations framing method
    7. Error control in data link layer
    8. Stop and Wait scheme
    9. Sliding Window Protocol
    10. One bit sliding window protocol
    11. A protocol Using Go-Back-N
    12. Selective repeat protocol
    13. Application layer
    1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
    2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
    3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
    4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.