Software Development Life Cycle Models

I was asked to put together this high-level and traditional software
life cycle information as a favor for a friend of a friend, so I
thought I might as well share it with everybody.

The General Model

Software life cycle models describe phases of the software cycle and
the order in which those phases are executed.  There are tons of
models, and many companies adopt their own, but all have very similar
patterns.  The general, basic model is shown below:

General Life Cycle Model


Each phase produces deliverables required by the next phase in the
life cycle.  Requirements are translated into design.  Code
is produced during implementation that is driven by the design. 
Testing verifies the deliverable of the implementation phase against


Business requirements are gathered in this phase.  This phase
is the main focus of the project managers and stake holders. 
Meetings with managers, stake holders and users are held in order to
determine the requirements.  Who is going to use the system? 
How will they use the system?  What data should be input into the
system?  What data should be output by the system?  These are
general questions that get answered during a requirements gathering
phase.  This produces a nice big list of functionality that the
system should provide, which describes functions the system should
perform, business logic that processes data, what data is stored and
used by the system, and how the user interface should work.  The
overall result is the system as a whole and how it performs, not how it
is actually going to do it.


The software system design is produced from the results of the
requirements phase.  Architects have the ball in their court
during this phase and this is the phase in which their focus
lies.  This is where the details on how the system will work is
produced.  Architecture, including hardware and software,
communication, software design (UML is produced here) are all part of
the deliverables of a design phase.


Code is produced from the deliverables of the design phase during
implementation, and this is the longest phase of the software
development life cycle.  For a developer, this is the main focus
of the life cycle because this is where the code is produced. 
Implementation my overlap with both the design and testing
phases.  Many tools exists (CASE tools) to actually automate the
production of code using information gathered and produced during the
design phase.


During testing, the implementation is tested against the
requirements to make sure that the product is actually solving the
needs addressed and gathered during the requirements phase.  Unit
tests and system/acceptance tests are done during this phase. 
Unit tests act on a specific component of the system, while system
tests act on the system as a whole.

So in a nutshell, that is a very basic overview of the general
software development life cycle model.  Now lets delve into some
of the traditional and widely used variations.


Waterfall Model

This is the most common and classic of life cycle models, also
referred to as a linear-sequential life cycle model.  It is very
simple to understand and use.  In a waterfall model, each phase
must be completed in its entirety before the next phase can
begin.  At the end of each phase, a review takes place to
determine if the project is on the right path and whether or not to
continue or discard the project.  Unlike what I mentioned in the
general model, phases do not overlap in a waterfall model.

Waterfall Life Cycle Model



  • Simple and easy to use.
  • Easy to manage due to the rigidity of the model – each phase has specific deliverables and a review process.
  • Phases are processed and completed one at a time.
  • Works well for smaller projects where requirements are very well understood.


  • Adjusting scope during the life cycle can kill a project
  • No working software is produced until late during the life cycle.
  • High amounts of risk and uncertainty.
  • Poor model for complex and object-oriented projects.
  • Poor model for long and ongoing projects.
  • Poor model where requirements are at a moderate to high risk of changing.


V-Shaped Model

Just like the waterfall model, the V-Shaped life cycle is a
sequential path of execution of processes.  Each phase must be
completed before the next phase begins.  Testing is emphasized in
this model more so than the waterfall model though.  The testing
procedures are developed early in the life cycle before any coding is
done, during each of the phases preceding implementation.

Requirements begin the life cycle model just like the waterfall
model.  Before development is started, a system test plan is
created.  The test plan focuses on meeting the functionality
specified in the requirements gathering.

The high-level design phase focuses on system architecture and
design.  An integration test plan is created in this phase as well
in order to test the pieces of the software systems ability to work

The low-level design phase is where the actual software components
are designed, and unit tests are created in this phase as well.

The implementation phase is, again, where all coding takes
place.  Once coding is complete, the path of execution continues
up the right side of the V where the test plans developed earlier are
now put to use.

V-Shaped Life Cycle Model



  • Simple and easy to use.
  • Each phase has specific deliverables.
  • Higher chance of success over the waterfall model due to the development of test plans early on during the life cycle.
  • Works well for small projects where requirements are easily understood.


  • Very rigid, like the waterfall model.
  • Little flexibility and adjusting scope is difficult and expensive.
  • Software is developed during the implementation phase, so no early prototypes of the software are produced.
  • Model doesn’t provide a clear path for problems found during testing phases.


Incremental Model

The incremental model is an intuitive approach to the waterfall
model.  Multiple development cycles take place here, making the
life cycle a “multi-waterfall” cycle.  Cycles are divided up into
smaller, more easily managed iterations.  Each iteration passes
through the requirements, design, implementation and testing phases.

A working version of software is produced during the first
iteration, so you have working software early on during the software
life cycle.  Subsequent iterations build on the initial software
produced during the first iteration.

Incremental Life Cycle Model



  • Generates working software quickly and early during the software life cycle.
  • More flexible – less costly to change scope and requirements.
  • Easier to test and debug during a smaller iteration.
  • Easier to manage risk because risky pieces are identified and handled during its iteration.
  • Each iteration is an easily managed milestone.


  • Each phase of an iteration is rigid and do not overlap each other.
  • Problems may arise pertaining to system architecture because not
    all requirements are gathered up front for the entire software life


Spiral Model

The spiral model is similar to the incremental model, with more
emphases placed on risk analysis.  The spiral model has four
phases: Planning, Risk Analysis, Engineering and Evaluation.  A
software project repeatedly passes through these phases in iterations
(called Spirals in this model).  The baseline spiral, starting in
the planning phase, requirements are gathered and risk is
assessed.  Each subsequent spirals builds on the baseline spiral.

Requirements are gathered during the planning phase.  In the
risk analysis phase, a process is undertaken to identify risk and
alternate solutions.  A prototype is produced at the end of the
risk analysis phase.

Software is produced in the engineering phase, along with testing at
the end of the phase.  The evaluation phase allows the customer to
evaluate the output of the project to date before the project continues
to the next spiral.

In the spiral model, the angular component represents progress, and the radius of the spiral represents cost.

Spiral Life Cycle Model



  • High amount of risk analysis
  • Good for large and mission-critical projects.
  • Software is produced early in the software life cycle.


  • Can be a costly model to use.
  • Risk analysis requires highly specific expertise.
  • Project’s success is highly dependent on the risk analysis phase.
  • Doesn’t work well for smaller projects.


And that’s it.  If you have any input, especially your views on
advantages and disadvantages of any particular model, feel free to
leave them in the comments and I can add them to my copy.

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444 Responses to Software Development Life Cycle Models

  1. plopjot says:

    this is tuttii!!!

  2. plopjot says:

    this is tuttii!!!

  3. HAMMAD says:

    Thanks.. very useful article.

  4. Nanda Kumar says:

    SDLC Models given here are easy to Understand and very good for Beginners like me.

    Thank you.
    Nanda Kumar.

  5. Shashikant says:

    Much helping and quick learning material …. Good Job Man…

  6. mickey says:

    can u give explanation for the other models as well as i have heard abt iteraton,protype and classical models

  7. maqria jenifer says:

    this article is superb and easy to understand

  8. I would like to ask “isnt maintenance part of Software development life cycle ? and if it is , then isnt it the longest phase of software development life cycle ?”

  9. Raju Arora says:

    Thanks for the information shared here. that was an interesting and informative. I had a good experience by participating in the Cloud Computing and SOA Conference in 2009 which is most influential Business Technology Conference covering latest innovations and trends of Cloud Computing, SOA and its technologies. I learnt lot of new technologies in Cloud Computing. And I am planning to attend 2010 edition as well. I found the information about the conference from

  10. payal says:

    Very good article about SDLC,n its a very good site

  11. saleem says:

    thank you post such an interesting life cycle model ,,,,
    I want to know about the Prototyping life cycle,
    can you throw some light on that,,,,,,,


  12. anu says:

    thanks,for a good explanation in an easy and understandable form.

  13. amit says:

    it’s really very good material.

  14. Bob Stewart says:

    The new free wiki based open-source technology systems and software development life cycle over at is worth checking out and even better still it’s creative commons so it’s free to copy, paste, edit and use …or for just under a hundred bucks you can get all the original files and tweak them to suit your needs.

  15. Srinivasa Rao Paidisetti says:

    Good overview. Appreciate it!!

  16. Al Amani says:

    This information is extremely great but can anyone tell me which companies use each of these models

  17. tom magira says:

    i really understand the SDLC…….., thank you sir.

  18. tom magira says:

    i really understand the SDLC…….., thank you sir.

  19. sweta says:

    The above models are very clear and understndable..
    where is the prototype model???
    i want it in detail…

  20. Great article very interesting indeed!

  21. Thank you for sharing good information.

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  23. Lunaa says:

    This article was great. Great help For my campus interview.

  24. bromley college teacher says:


  25. bromley college teacher says:


  26. ramya says:

    quite informative……..

  27. 122artina says:

    Thanks, this is brilliant! What about rapid prototyping or rapid application methodology?

  28. Jeff PM says:

    I’ve been trying to determine a distinction between the iterative and incremental model and I can’t figure it out… I’ve read various information and the two terms are often used interchangably. The reason that I am asking is that early in the comments thread Jeremy stated “XP is iterative *and* incremental (like RUP and essentially all modern processes).”. What exactly is “iterative *and* incremental” as opposed to just iterative or incremental?

  29. Bala says:

    Sir, I want details about Prototype model & WIN-WIN spiral model

  30. Preeti says:

    hello , this is really good document.
    i have some questions regarding project, which life cycle u prefer for it

  31. MradulShikha says:

    it’s really verry good is exact,simple and short.

  32. abhi says:

    nice content.Thanks

  33. SUBATHRA DEVI says:

    hai.this article gives a clear view and exact definition,I would like to thank you,

  34. Nixon says:

    wow…really good job…..keep up the same work

    i just wonna ask u a qu ?

    may i know the books u refere? any particular Authora??

    plz? & thk u

  35. pradeep Nannapanei says:


  36. Joey says:

    I have been asked to introduce a suitable lifecycle for a payroll system. From what I have read, the spiral lifecycle seems most suitable.

    Would you agree or am I wrong in my decision?


  37. Ariel Barrett says:

    This is very informative but do u have anything on the object reuse model and the formal transformation model?

  38. Artemis27 says:

    Thanks you so much!!

    I needed quick references for my oral examination!!

  39. Purshotham says:

    It’s really helpful…..

  40. vijay says:


  41. Dick Jockey says:

    This article made me sh!t my pants!

    thank you so much!

    ps: my pants are squidgy now

  42. Betty Swollocks says:

    reading this article was so exhilerating that i quite literally shit my pants,

    thanks a bunch

    Betty Swollocks

  43. RAJ says:

    anywhere i cud find info on the fountain model?

  44. Danny Goldsmith aka 1 testicle says:

    i have 1 nut n caused it by playing golf wiv my daddy

  45. dfrith123 says:


  46. Amita says:

    Hey Ray,

    This article helped me a lot in my s/w engg assignment.. Thanks for posting this information.


  47. subrata says:

    I liked the article, its is explained in very easy way. Very useful information for SDLC. Now i am exploring UML and SDLC.

  48. Duncan says:

    Nice simple description. A couple of comments and a suggestion.

    Most real processes tend to be a mixture of SDLMs. The real trick is to pick a lifecycle very early in the project and stick with it. Each has its uses (with the possible exception of the waterfall).

    The article could benefit from a ‘type of project to apply it to …’, i.e. V model – high assurance safety/security critical, incremental – database or MIS development

  49. DHANA says:


  50. Freddy... says:

    Among all those confusing huge chunks of sentences written about Life cycle models, this is simple, crisp and but still effective…
    Would be helpful if more could be added related to agile, RAD, JAD, RUP, etc.,

  51. mukid says:

    i fancy u pooja

  52. Darren says:

    Thanks a lot this has helped so much with my university assignment so gratefull thank you

  53. azam says:

    Disadvantage of Developing Programs with No SDLC Mode

    Lack of proper documentation is one of the reasons why a program with no SDLC model is undesirable. There’s no problem in the implementation of software but with no SDLC, there are no documentations to support the development of the program. Programmers could create their own documentation, but this is only for the program and nothing else. The philosophy, studies on why it should work; development and troubleshooting are parts of proper documentation which is outlined in SDLC. A program that has no SDLC cannot be duplicated if there’s a documentation that identifies the answer.

    Another disadvantage of developers who don’t follow SDLC is the inability to handle programs with complex needs. In house developers may be able to force themselves to create programs but the larger picture is missed. In a business world, developers have to work with business managers and there are certain needs that should be properly outlined.

    Disadvantage of Programs/Websites with SDLC Model

    Thinking about the disadvantages of a SDLC model is like looking for a needle in the haystack. But the closest disadvantage anyone could think of SDLC is the difference between what is written in paper and what is actually implemented. There are things that are happening in the actual work that the paper doesn’t see. This gives a good impression for the clients especially for 3rd party developers but when the software is actually launched it’s on a very bad situation. The actual situation of software development could be covered by fancy paperwork of SDLC.

    Another disadvantage of a program or software that follows the SDLC program is it encourages stiff implementation instead of pushing for creativity in different software. Although there are SDLC models where programmers could apply their creative juices, it’s always in the realm of what is needed instead of freely implementing what the developers think of necessary in the present environment. There are so many things that could be done by developers if there are no boundaries or limitations in what should be developed.

  54. Michael Akinrinade says:

    You make my job easy. you simplified the models in SDLC. This is good for assignment purpose. Thanks Raymond

  55. TSHOLOFELO says:

    Your article was simple to understand and very useful for my assignment work.It helped me in studies too.thank you raymond.


  56. pooja says:

    plz suggest which model should be used for warehouse management system

  57. Rahul says:

    thanx you your data help me a lot in my studies & in project .

  58. GHOST says:


    thank you for sharing all information it is greatly appriciated.

  59. arnold says:

    Hi nice and informative article regarding spiral model, may i know about water fall model and iterative waterfall model?

  60. faysal says:

    can u pls talk about the dependability measurement attributes

  61. Harini says:

    thanks for the information provided… it was useful for my assignment work.. it would be fine if you could include RAD model also

  62. trisha says:

    very simple to understand and also gives a lot of information

  63. Thanx 4 the material.

  64. Thanx 4 the material.

  65. Lenny says:

    Yur sites th BOMB son
    big up yer lyf cycl


  66. yukesh says:

    your article contain valuable information…….
    is there any relational between each model ?

  67. jose says:

    thank you for this great information it will be a great help for my final year project.

  68. bravo2305 says:

    Thanks, i appreciate for your dedication on this chapter of software development more especially your brevity is awesome. I had like to ask for an additional tutorials about Component Based software development & reusable software development models.


  69. MIRZA says:

    Your article is too simple to understand and very useful for my assignment work.It helped me in my studies. but apart from data your link have more comments. thank you.

  70. dilshi says:

    Thank u loads for this.. was very helpful for one of my projects…

  71. vaibhav says:

    Shukriya….tussi wadda changa kaam kitta hai…….

  72. vaibhav says:

    sahi hai bhai hindi me bole to dhanyawaad……..,,,,shukriya,,,,,,so allah haafis,,shabbakher,,,,gudbye

  73. v says:

    say me about object oriented model

  74. v says:

    i want to know about object oriented model

  75. Sachin says:


    This is very nice and informative.
    Thank you

  76. Lama says:


    thank you for all information but what about the evolutionary model?

  77. vidhya says:

    Your article was simple to understand and very useful for my assignment work.It helped me in studies too.thank you raymond.

  78. Naggy says:

    hi this article is very useful

  79. Naggy says:

    Hey its really useful for me.. But the content is not enough.. Nice article…

  80. bistro says:

    very useful diagrams. thnx all

  81. Bajrang says:

    This is a good article to understand as a newbie. This is really helpful to understand the basic concept about SDLC.

    Thanks a lot…


  82. Jai Shree Vohra says:

    It is really a helpful artical, and helped me a lot in my study through SDLC. The language is clear and easy to understand.
    Thank you so much.

  83. Reena Bathula says:

    Hey Ray!! I liked how this is explained in a clear cut way ..I liked the points way of advantages and disadvantages.I learnt a lot through this paper.I liked how it is presented..

  84. bhaskar says:

    This is too good and easy to understand.this really helps me.


  85. Kris says:


  86. ace says:

    this is good dude
    thanks for this info!!!!

  87. Rambo says:

    Thanks for your efforts. Good article and to the point.

  88. Sundar says:

    Good one ya!

  89. bhavna says:

    hey… this was exactly what freshers like me look for… thanks for making it this simple to understand…. btw.. can u explain RAD model n inform bout what is 4th generation model???

  90. K.KARTHIKEYAN says:


  91. Andy says:

    Wow! The comments and feedback are becoming longer than the article!

    I have been seeing more hybrid models for software development, but I am curious as to whether there is an SDLC approach that attempts to take a taxonomy of all software dev processes and create an approach to SDLC that is custom tailored as appropriate to the project.

    This would be an alternate to the current trend-take a model and adapt it to the project’s needs in a haphazard manner.

    There are several good taxonomies available, but there are also certain areas that I have been unable to find taxonomy. For example: requirements representations. Has anyone seen a comprehensive taxonomy of requirements representations? The IEEE definition includes the form of representation as a part of the definition of a requirement. But can’t a requirement definition be created independently of the form of representation?


    Andy-U of MN CSci student

  92. Madhu says:

    This is too good and easy to understand.this really helps me.


  93. Carrot says:

    well thnx man

  94. Nandhini says:

    its satisfaction

  95. shwetha says:

    It is very simple n informative too..

    thank u

  96. mousumi says:

    A good article.Was quit helpfull to understand the SDLC in short.

  97. tariq bhat says:

    i am very very thankful to you for this topic.Before this
    my mind was full of confusions about this topic.
    Again very thankful to you

  98. godwin says:

    how can i get full detail of the topic of system life cycle.
    can any one give me information on our to get it.

  99. please there are more software development models that are not here some of which are build and fixed model, implementation model etc.

  100. madhu says:

    it helps me to understand basics of SDLC….

  101. freda castro says:

    this site is good and very helpful for us.

    god bless!!!

  102. Abhi says:

    i think s/w eng is so vast & nobody is expert.

  103. Caryl Carson says:

    Great info, have been trying to get a good basic understanding for a long time. Thanks

  104. Zaniee says:

    hye i think this is the most good explanation i read. keep it up raymond lewallen.

    but i want to ask is there any explanation about system development life cycle (SDLC) which is each phases are overlap between other phases.


  105. it is very good article.

  106. Shiva shankar reddy says:

    Thanking you. it is very helpful for us. But some more models are expect from you like proto typeing, RAD model.

  107. Ganesh adiga says:

    Really its must need for beginners in SDLC……

  108. Kadenyi says:

    Thanks. you didnt mention code and fix model

  109. Naga says:

    Thanks U gave what we need and we expect more from u.

  110. Sheela says:

    Thanks for sharing your knowledge and skills, this documentation is very much usefull for me.

  111. Ragoubady says:

    Nice artical and its simple, short and having useful information.


  112. shachi sharma says:

    thanks a lot for providing such a precise information about the software development life cycle…it has really made my work easier. i am easily able to understand this important portion of software engineering very well through the information you have provided.

  113. Athar Nawaz says:

    Hi………those para r very helpful to understand SDLC
    , So like thanks to body, who uploded those mattes

  114. Antony.J says:

    This site is useful for the software builders.

  115. Sandeep Kumar says:

    Really Informative…

  116. saniya says:

    this is fabulous!
    but very boring to read!
    this should be short & sweet!

  117. Zandy says:

    Hey Raymond u’v been a great help ur article helped me a lot.Bi ups to you.Thank you.

  118. sathish says:

    thanks a lot for this, will u post some other models


  119. shibu augustian says:

    it very useful for me

  120. selvi says:

    good artical on sdlc modell
    its veryuseful for us…

    i have to verify this url only… abt s.w testing


  121. SyedOmer says:

    Hi All,

    Really very informative and interesting topics…


  122. SyedOmer says:

    Hi All,

    The above S/W development models are really very informative..


  123. Niranjan says:

    Really a good one with minimal lanuage helping a begineer to understand terms and their scopes.

  124. Reshna Raghu C says:

    Excellent article.Helped alot for improving my knowledge.

  125. Reshna Raghu C says:

    Excellent article.Helped alot for improving my knowledge.

  126. Reshna Raghu C says:

    Excellent articale.Helped alot for improving my knowledge.

  127. Lucky , LUMS says:

    Is software project planning important?Where does planning lies in the SDLC? What is the importance of rsik analysis? If project fails then is it totally depend upon development Model or others factors can be blamable?

  128. nishanthan says:

    hi thanks its vry useful to me … i wanna check wit u some thing .. hey can i use spiral model for the big cash flow management software ….if u noe plz reply to
    if u can plz help me …

  129. shantanu says:

    this article is really good.PLZ MAKE SUCH TYPE OF ARTICLES MORE……….. THANX A LOT

  130. rajesh says:

    its very good for the novice learners who could understand as fast as they can.this is one of the best material

  131. sandhya says:

    thanks. nice article

  132. Ravi kumar says:

    This is a good article. Eventhough, we are talking about new models like XP, SCRUM, RUP, at the end is it not a typical waterfall model executed for the small scope considered in that iteration?

    Can you throw some light on the criteria of using different models/methodologies in software development and think of comparing on some parameters . Like when we can use WF, when we can use XP and when we can use SCRUM or RUP or DSDM or RAD or Iterative etc.,,

  133. KS THANGAVEL says:

    in V -MODEL diagram

    u are not specified the UAT TESTING nad not concen code it good article except V MODEL


  134. ks thangavel says:

    in articles
    in V MODEL not specified UAT testing and coding
    consider it

  135. Sravani says:

    Its very nice and much helpful.
    Thanks a lot

  136. Bhanu says:

    Good article on SDLC in a simple language, it is more informative and easy to understand the different models. Thanks.

  137. althaf says:

    what is FISH MODEL?

  138. loga says:

    thank u. really helpfull article for my assignment

  139. rukaya says:

    Please elaborate the models. explainging in detail will mahe it clear to understand it well.
    Any ways thanks for the article. I can’t say it is a good one but can be helpful to beginners.

  140. Jay says:

    very helpful, our text book only provides one example. I appreciate these thourough examples without them I;ll still be clueless as to how to do my homework.

  141. Kris says:

    Awesome stuff. Priceless. I’m an MBA for more than 2 years now, I never understood the differences better before. It cleared all my small but important doubts. Thank you for posting them.

  142. Gopal says:

    Really superb article ….ever I have seen.
    It’s helpful for all

  143. Gopal says:

    Really superb article ….ever I have seen.
    It’s helpful for all

  144. Stephanie says:

    I’m doing an assignment and i dont know if prototyping is a model or if spiral model and RAD are examples of prototyping

  145. yar says:


  146. rashmi dongre says:


    IN the release , please mention about evolutionary , RAD models also ……..


  147. rashmi dongre says:


    The content is really good , well my question according to u , what is requirement

    i. condition.
    ii. standard
    plz answer the question ………..

  148. justcool says:

    very good informatinon on s/w dev models

  149. Sumanth says:

    Thank you Raymon,
    This is good article with simple words, which is simple to understand

  150. Josephine says:

    Appreciatively, this write up has really helped me in my final year project tks a lot

  151. Mohamed says:

    Thanks this is great article

  152. Gowri Reddy says:

    this is like a gift for beginners, thanks …..

  153. Lol says:

    That is very interesting information. I have worked several years in the automotive industry, in engine management system where the V-cycle is widely used.
    I have now changed industry and struggle with the implementation of an ERP system. More specifically, we struggle with all the modules communicating with the ERP system, such as generation of sales report.
    Anyone has an idea of what cycle works best for that type of application?


  154. Farook says:

    Nice explanation…. Very easy to understand… Really good job

  155. Babal hayer says:

    Thanks Its Realy Good & Understandable.Its Limited But Very Clear & Understandable.
    I Like The Digramaticaly Work.

  156. jasmin says:

    its gud n well organized article ;Thanx 4 such a nice effort

  157. naleen chathuranga says:

    thanks for your information

  158. vaibhavi oza says:

    Hey i have made a chat sercer using C#.Net bt now at the time of documentation i dont know which ASLC model i should choose???

  159. Ben Dover says:

    Nice Work Yeh

  160. Diala says:

    The best breakdown of SDLC models, I have ever come across, I’m saving this.

  161. mahendra says:

    good. but not sufficient

  162. Bijuraj Sarangi says:

    The explanation is quite well.It would be helpfull for beginners if some more models like evolutionary prototype,throwaway prototype,iterative enhancement models are involved and there is need of a more in depth exaplanation of the topic.

  163. visagan says:

    you are handled the diff models
    how to develop the new models?
    if you are focus in requirement to sys.testing is this enough
    ur answer is yes- ok
    if no means which area want to cover
    pls reply in my id.

  164. francisca says:

    please i need information on sdlc, mostly the advantages and disadvantages,methodology

  165. Joanna says:

    It was quite good the imformation. However I think you could have gone more in depth about the pros and cons and given examples i.e why is is poor for “Poor model for complex and object-oriented projects.”? Also maybe a introduction to RAD would have been good. However a good document

  166. mona says:

    Thank yiu for your information . They are fantastic!!

  167. the stig says:


  168. it’s very good as a start. thanks for your info.
    Note-> Agile method come under which modle: Iterative or Incremental modle.
    i have some doubt.

  169. Hi, this is vishala what are the models u given are perfect but i want on Agile model and which situation we can go for this type of model

    if u provide the answer it will be a great favour for me.

    thank you.

  170. Stewart says:

    How about a little Rational Unified Process for software development??

  171. priya says:

    Thanku so much..It’s very useful 4 me…

  172. SUKUMAR REDDY says:

    Very Good Info for starter. thanks for your Information.

  173. Saadia Iftikhar says:

    I think its a wonderful post. Only one thing i would like to comment on Spiral Model. Its disadvantages could also include that: Since changes can occur after every customer review, too many changes can affect the quality.

    Please guide me if i am wrong.

  174. Geetha says:

    Good and a usefull article.

  175. Kartheek says:

    Hi Mr. Raymond Lewallen

    Im kartheek.. im working as QA engineer India.

    Actually i want some information about newly introduced SDLC model… Think its name is Gen3
    If you know about that… Im expecting some valueble information from you.

  176. That’s very good look. Testers and coders see more clearly where they should be standing, and when they should implement their jobs. I can find myself where I am in those cycle. Gratefully!

  177. NARTEY K. RICHARD. (GHANA) says:


  178. root123 says:

    That’s a good list to compare and choose development models to meet specific requirements….thanks

  179. Redd says:

    can u tell me the evolutionary model and reuse based development and formal model and their advantage and disadvantage??

  180. vineeta says:

    thank u so much .this is a very useful article for me

  181. raj says:

    Can you please explain about Agile process? Thanx raj

  182. dev says:

    thanks for help

  183. Marinos says:

    i make a homework for my university and i can find advantages and disandantages adout life cycle;Can you help me.

  184. Syed Tosif Raza says:

    Its really helping artical

  185. Ambrose says:

    How come you don’t have any information on the Evolutionary Prototype Life Cycle Model? I would really appreciate if you would add this to your page.

  186. S.Anil Kumar Reddy says:

    Thank U for giving such useful information, this is covering almost of information that is required

  187. Lizzie says:

    thank you for a simplified version of the SDLC models, all this goes in my task assignment :o)

  188. Kenny says:

    finally, i can actually understand this, thanks for putting it up, its really helped me with my IT assianment.

  189. GAURAV MEHTA says:

    this page really acts as a systematic guide for the software development

  190. sachit singh says:

    can u plz discuss prototyping model in d same manner…

  191. RAHUL RIZVI says:

    this a very nice article that helps the students to understand the concept very well also it acts as a guide for the one who are designing the software fror the first time.
    I am really impressed with this article!!!

  192. Nair says:

    Great post.. Helped me a lot

  193. programmer says:

    some of this information is also from

    did you write this yourself? honestly?

  194. Reddy says:

    Very good work

  195. Ankunda Anthony says:

    This document is informative. You explained alot in few words. Thanx

  196. Vijaya Kumar says:

    Really fentastic…..searching in various sites but couldnt able to get proper info….

    really good material and really it was short and detail…

    Good job Keep it up….

    awaiting some more from you….

  197. Anil Bora says:

    Really it is a cool and informative.
    Thanks for sharing it.

  198. deepak says:

    what about evolutionary development? fountain approach, formal transformation, re-use oriented approach etc. Would like to know about those ones as well. Please provide me with a link if u know of any

  199. sridhar says:

    its a nice job very easy to understand boss

  200. jyoti says:

    very valuable

  201. Bhaskar kanti says:

    its nice that every body liked it. really its to the point and at the same time it would be better if u provide a link to other page to detailed descriptions. and u can include other software models also like Extreme Programming and Concurent engineering.

    any way thanks

  202. Neelima says:

    pls give me the precise information abt v-v model with diagram

  203. TechnoPhile says:

    Wow! So many replies and ticking…

    Guess its because Google has listed your link in first page! Well, I liked the V-Shaped LifeCycle Model representation. It explains the crux and is easy to understand. With all respect, good work.

  204. Alka Khosla says:

    Excellent, Thanks for giving such a simple article

  205. Anu says:

    Thnx a lot, it is really useful..
    Keep up the good work….

  206. raja says:

    but u didn’t mention refinement of v model.pls provide that info………………………..

  207. Naveen Vijayagiri says:

    thank “U” Mama
    i wish you all happy long life and prosperity

    i am trying to Keeping touch wIth u

  208. suseentheran says:

    its very useful post….thanks a lot.

  209. sale birniwa tasha says:


    i wish you all happy long life and prosperity

  210. Raymond
    i wish you all happy long life and prosperity

  211. eirlivy says:

    ei.thanks for this site but cani request for the informatrion about system development life cycle its history,importance, advantages and disadvantages>>pls\

  212. Hari Prashad Pant says:

    Thak U very much sir for your kind coopereation by making this valuable notes on SDLC models to be viewed on WWW globally. This really made me to understand different models easily.

    Best regards
    Hari Prashad Pant

  213. Jitendra, what are you not convinced of, and what do you think I was trying to convince you of believing? I was not aware this article was attempting to convince anybody of anything. It is an information article, not a marketing avenue.

  214. jitendra chauthani says:

    dear sir,
    have read about your article,
    but i am not totally convinced,
    these days formal methods are increasing exponentially.on the other hand software industries are using mixture of life cylce models……… like the win-win spiral model and the formal methods..

    so what is the best practice to be followed…
    also tell this in regards of the sowtware size…small..medium.large

    and if possible mail me at

  215. PROMISE says:


  216. Rizwan says:

    This is really nice.My project manager really appreciates it.

  217. SIVAJI says:


  218. SIVAI says:


  219. Shyam says:

    This is simply superb, ideal way of explaining SDLC and anyone can understand

  220. Decoda says:

    Very Informative but I would like to know about a few more other models. Models like, Evolutionary Development, Formal Transformaton and Reuse- Oriented System.

  221. Winn Mar Saw says:

    Thanks a lot for your information here.
    It really helps with me. :-)
    Really, thanks again!

    Best regards,

  222. surekha says:

    thanks for sharing this information..
    it was very helpful to me and simple and made all my points clear regarding the models thankq very much

  223. Good explanation and comparision on SDLC Models, I think most of the companies/products use a combination of models, like Incremental and Iteration / water fall to get the best.

  224. sunitha says:

    it is easy to understand for each model advantages and disadvantages also given

  225. E Murugan says:

    This is very nice and useful article for the people who are in begining level in s/w industry.

  226. Raghu says:

    Its good to consolidate models in one place

  227. Venkata Reddy says:

    Good knowledge provided about SDLC models.

  228. Somasundara Rao says:

    Its really Good one. Explained in simple text with good pictorial representation. Thanks.

  229. Somasundara Rao . R says:

    Good one. This is what looking for. Explained in simple text with good Graphical representation.
    Somasundara Rao

  230. Kanthi Kiran says:

    Its very simple n best to understand the SDLC models btwn can u also include “Fish model” so that all would be at onc place.

  231. SK says:

    Hi..dude this is a cool one.

  232. Mak says:

    Great help for interview preparation!!!!!

  233. imran javaid says:


  234. Rahul Soni says:

    Hey, it was good overview of the SDLC. But I wonder, should i fit XP and Agile Methodology. If possible, can you please provide some details on that too.

  235. Great Article, thanks

  236. Rama Swamy says:

    good knowledge provosion to begenners

  237. Parthasarathy Raja says:

    Good One.Ease is the strength is this article.

  238. Veenu says:

    THis is very good blog i get while searching on google…
    This article explain the SDLC in a very good manner. For the begineers it is a very good article.

    Thanks for this article.


    Veenu kapoor

  239. radhikag1 says:

    ITs wondeful, and simple, catchy too

  240. josif says:

    really thanks alot for this topic………

  241. Jagadish says:

    very Informative.

  242. Anand Prakash says:

    It is very fruitful content

  243. Great Article, thanks

  244. Rkreddy says:

    Raymond Lewallen its really good one,
    but iam suggesting its better to eloborate more about the difference between the
    high level and low level design under the design phase instead of giving it in one sentence,
    over all it is excelelnt

  245. Dhvani says:

    what is the difference between SDLC and Agile methodologies?

  246. jayakumar says:

    Its really good..but if u give in simple english it will be more usefull to all…

  247. Actually the Process is very much easy and adoptable for good output.

  248. Munendra says:

    this is very good for s/w professtional…


  249. ChinmayNaidu says:

    Good article. Some more categories must be involved like RUP,XP etc.

  250. mansoor says:

    very useful and a clear explanation of the sdlc models

  251. Thanks…it’s a very good article.It is very important that you have a sound knowledge of software development life cycle if you want to make a software that is good and more cost effective.

  252. Mritunjay Sharma says:

    Hey I too agree about its importants, i could have been even valuable if he you could have given of all these models.

    But i would really appreciate if we can get little more deeper explanation of all these models with one to two examples.

  253. Rizwan Pervaiz says:

    Difference between Waterfall method and linear Sequential method?

  254. Rizwan Pervaiz says:

    Difference between Waterfall method and linear Sequential method?

  255. Rohit Tewari says:

    It is a very good article. Thanks for sharing it.

  256. Sujith Shenoy says:

    You kept everything very simple in this article. Itz a really good summary of different software models commonly used by many software firms.

  257. p says:

    when i found anather questions ans?

  258. ysj says:

    this is a very good thim. because when you have ans but you donot found then we found heare.

  259. arunkumar.R says:

    its very nice ……
    i think it wioll help me in my project work…………

  260. Chandrakant Bandmantri says:


    Thanks a lot for your vey good article.
    Could you throw some light on Iterative, Prototyping, RAD ?

    – Chandra

  261. baka group says:

    its…too good….

  262. Zia says:

    Very much helping and quick learning material …. Nice work

  263. very wonderful information.thank youso much

  264. very wonderful information.thank youso much

  265. Clara says:

    This was really very helpful. Good information about SDLC. Thanks

  266. Abrar Ahmed says:

    Amazing.. thanks

  267. YW says:

    This paper gives me a good explanation about SDLC.

    Can someone inform me, where I can found a comparison between SDLC used by firms (in US for example)? What is the most popular used SDLC by the firms or software house? Is there any surveys about that?

  268. Rakesh says:

    This paper has given me a clear idea about the SDLC model. In the disadvantages sections, the Risk can be explained clearly about what are the risk factors can be taken into consideration in that particular type of model. Thanks!

  269. KJS says:

    Good comprehensive overview! My only suggestion would be to add a Maintenance phase.

  270. srinivasa kethireddy says:

    Good article. we can refresh very fast our self.

  271. Anandurs says:

    Hi Ray,
    Its really a useful thing in brief, Thanks for it.

  272. FARZANA says:


  273. Sasi Varma says:

    Good, very useful posting. Thanks

  274. saba says:

    Hi!! Thanks a lot .This article is very good & it helped me a lot in deep study of the software lifecycle development models.Thanks again.

  275. morry says:

    hey there extremly well written in an understanding way..ive an exam on theses:) so thanks a miliion.

  276. dolly says:

    HI RAY

  277. zinat says:

    this is very good.
    thanks a lot.

  278. zinat says:

    this is very good.
    thanks a lot

  279. Othniel Imaobong says:

    this write up is very interesting and educative

  280. dilshara says:

    was a real important resource for my teaching material.. thanks and keep your work continuing with such important service to all… great work!

  281. sunitha says:

    Its really good for learners.By the way I need one more help..can any one tell me where I can find the trial version of Test Director

  282. Chetan says:

    A very informative post. Explained in much simpler words and a great help to all developers mostly freshers.

  283. Radhika Chari says:

    Hey fantastic job. All information in one place. Tanks a Ton.

  284. Varun says:

    This article help me a great deal in my project on sdlc models and am just saying thankyou.

  285. YASIR says:


  286. david says:

    this is the best description in which i never saw about SDLC

  287. Olatoye says:

    I must give credit to you rlewallen, for supplying such detailed information the various types of SDLC Models. I tell you what, I went for an interview Today for a Test Analyst role some where in London. The face to face interview and all that went well. I was happy. BUT there was the TEST (Combination of Multiple choices and theory). I tell you, if I had seen this blog earlier, I could have earned myself an extra 17 marks for just explining what the V-model was, with the level of clarity you provided. I need to get in touch with you some how.

  288. kumar says:

    Please mention the out come documents of each phase of the SDLC!

  289. swarna says:

    Nice article, this article is more helpful to the people those who are involved in Testing track

  290. khushbu says:

    hi, this is gud article but u wrote in a very high manner , please write in simple words nd also in that way tht a student can read it . i m from india . but i found it very nice and optimistic.bye and thanks

  291. Raj says:

    Its a really gud article for figuring out differences between different models.

  292. Naina says:

    Excellent article. Smart and simple. Summarizes SDLC very well. Good Job.

  293. ARUN REDDY says:


  294. PrabhuSV says:

    Its nice to see these models at one place for reference and comparison for process people. I wanted to see the Extreme Programming & Evolutionary Appraoch models.
    — —

  295. pradeep bhumani says:

    this presentation was very good and easily understand any one i hope people send these type of presentations
    thanking u
    bhumani pradeep
    software testing engineer

  296. Sanjeev Kumar Malde says:

    Good and informative article in short..

  297. Ravi Shankar says:


    This was a nice article related to development life cycles. All the models are described in this article to a great extent and the one who reads this article will feel that its definitely good.

    very good and interesting……..

  298. Ravi Shankar says:


    This was a nice article related to development life cycles. All the models are described in this article to a great extent and the one who reads this article will feel that its definitely good.

    very good and interesting……..

  299. Mahendra says:

    Very Good Article and thanks for keeping simplicity.

  300. Steven Clough says:

    Thanks for the information, because of this we was able to quickly write up some pointers for our presetasion of Project Management where we need to talk about the importance of the project management and the system lifecycle.

  301. Prajakta says:

    Its a good article and i find sufficient to get knowledge about SDLC.but i would like to know more on prototyping model…

  302. prathyusha reddy aala says:

    This is a real gud site for the ppl who want to know the basics of how a project is handled btw i doubt if V shaped model is an SDLC . Gud work :-)

  303. Sunil says:

    Thanks ,
    I got solution for my query

  304. Semon KH says:

    thank you for the help

  305. Semon KH says:

    please i want to ask about drawing a sketch of project life cycle

  306. Nisha Hemamalini says:

    Hi All,

    This article is very useful one.Every Software professionals should go through it.

  307. ysib says:

    I am trying to decide what sdlc use in my project.
    due to lack of expertise cia is strongly considering buy off the shelf software, which would be the best methodology to use if you are going to buy the software?

  308. savitha n says:

    A good one,but as to be in little more depth for better understanding.keep it up….

  309. uday says:

    Its G8 work.
    Thank you for providing these details

  310. Prashant says:

    Good one …fundamentals of the SDLC ,very useful for someone new to SDLC

  311. Balkrishna says:

    Indeed good article throwing light on various SDLC models.
    Almost got cleared the imbroglio between various modles.
    Thanks a lot :)

  312. Rahul says:

    Good One !

  313. Steven Clough says:

    I’m doing an assignment at college on System development lifecycles.
    This information is very well pressended and is helping me with some of the task that I need to complete in the assignment.

    Thank You

  314. Urukundappa says:

    Excellent document on SDLC models. I am suggesting you to provide in detail information.

  315. Lil Pimp says:

    On your question about the v-shaped waterfall
    please check this link im only on my HNC/HND of computing but i hope this link helps u along

  316. Roushan says:

    Thanks for the article. But from my point of view better to elobrate the topic

  317. GovindaRao Chalamala says:

    This is very Nice Article, Thank you very Much. i want to know about Iterative Model.
    what are the advantages and Disadvantages.

  318. Vincent says:

    Thank you very much! it’s useful to me, but do you know novel cycle life? I wish to know any new cyle life used in the present time.

  319. lone says:

    Thank you very much,it’s useful to me.Can you describe the prototyping model?And I donnot understand the difference between the 1st model in incremental model and the prototyping model.

  320. Saurabh Kashyap says:

    Really this article is very helpful for beginners.I was looking for such article.Thnaks a lot.

  321. Saurabh Kashyap says:

    Really this article is very helpful for beginners.I was looking for such artical.Thnaks a lot.

  322. Saurabh Kashyap says:

    Really this artical is very helpful for beginners.I was looking for such artical.Thnaks a lot.

  323. Rudra says:

    This article is helping me a lot.
    Thank You and good work.

  324. Shehan Niyas says:

    Wow u’ve got exactly wat i need.
    Common Life cycle models n their advantages n disadvantages.
    A very good site. got wat i needed,
    Keep up da good wrk.

  325. Bepenfriends says:

    Hi Ray,

    A very good post. I know only waterfall model and worked on that. Now i know a little in other models too.



  326. anurag srivastava says:

    for sdlc

  327. anurag srivastava says:

    fodr sdlc

  328. Tapan Bhardwaj says:

    it very good to better know abut SDLC

  329. ramana says:

    a very good article …i need complete information regarding spiral model

  330. Ryan Xj Pinoy says:

    thanks to the author. :-)
    by the way guys, do u have a Work breakdown structure for these
    software life cycle model? i mean, the one that is based from the
    ISO12207 standard?

  331. Nilima says:

    Great article,
    Very helpful for me to work on my projects.

  332. Grim reaper says:

    The concept of life is very uncertain, you should rethink and go to bed. Maybe some chocolate or you could just leave some pizza for me. I know you love me really.

  333. vasudha says:

    this is a great article .this realy helped me a lot to clear technical round of my interview. can you please share some information on software testing techniques

  334. Odukudu Bernard says:

    This is a great clarification

  335. kunal says:

    its good
    contains good info
    i think they have to give more details

  336. Panchaxari says:

    Very informative. Thanks

  337. Deepak Anand says:

    I find this article better than any SDLC search results till date. Definetly worth your time.

  338. Heba says:

    Please what about RAD???? pros and cons

  339. Harish says:

    Great Article

  340. jams says:

    can some one let me know what is Rapid Application Development(RAD)

  341. Zaki says:

    I don’t see the UAT in the V-model.Can someone throw some light on this?

  342. Nice article to refresh abt SDLC….Thanks…

  343. Lloyd says:

    to Mr. Lewallen, thank you very much for posting the SDLC, ill be using it for my software methodolgy

  344. Sandesh says:

    Nice Work and very helpful for me in getting differences in all the different models ..

  345. Abhijeet says:

    That was really a nice topic, very helpful..

  346. Jeff says:

    Can anyone help me.. BTW, great article… uhmm what model should i use for this kind of project.. actually its for my thesis… an online expert system that uses schema matching for data warehousing… please help me.. thanks in advance…

  347. Ramesh Reddy says:

    Nice work. Very much helpful for me. Thank you

  348. kumar sundaram says:

    it is very simply and easy to understand .

  349. Ashok says:

    This site is too good

  350. Francis says:

    This is a good material. But, I am not familiar with the V-shaped Life Cycle Model.

  351. Markov says:

    Very good article about SDLC.

  352. sai says:

    Very Good

  353. Prem says:

    Great article and worth having Five stars. Lot of valuable info presented in succint paras. great.

  354. suryakiranmurthy says:

    can u pls discuss about the vv model ?

  355. sridhar says:

    Excellent material…

  356. Prudent says:

    Documents seems to be good , our suggestion is to go little bit depth

  357. Prudent says:

    Documents seems to be good , our suggestion is to go little bit depth

  358. Priya says:

    Thank you for sharing this information. I could not get such an information anywhere else.

  359. Richmond Enriquez says:

    Hi, This is what I’m looking for. You’re article is very much informative and it helped me in my software engineering course. Thanks a lot.

  360. Hoch Srinivas says:

    The Information is Helpful Especially For Basic Learners.Thank You.

  361. Srinivas says:

    Hi. Had there been info about when to use what would have been very much appriciatable . This info is great and useful for most of the S/W engg

  362. Dilip says:

    Data Provided Is Good,Especially The Pictorial Representation Is Impressive.Thank You.

  363. DCP says:

    What hav been explained in wATERFALL Model is not seems to be correct, can u plz check b’coz the requirement shpul be mapped with UAT and rest of them in the same way, on seeing this many would be miss lead so change as soon as possible.

  364. Sanjeev says:

    Information is good. But I think this is not enough information. Very less ponints are mentioned.

  365. Diyi Srinivas says:

    Advantages&Disadvantages reg models are not clear i suppose.
    I feel that General Life Cycle model should be updated.
    Thanks for nice postings.Thank u once again.
    Srinivas Diyi

  366. Minal says:


    One more question, where does the rational unified process fall in these. Isnt that another type of Software development methodology?


  367. Minal says:


    This is a great article.

    I just have one doubt. I was thinking that wouldn’t Spiral model alos hav the same problem as the Incremental model i.e. “Problems may arise pertaining to system architecture because not all requirements are gathered up front for the entire software life cycle”

    In the spiral model, how would you make sure that you have rightly estimated the scope of the project in teh first phase of planning?


  368. Lokanath Reddy .D says:

    Simply , it is wonderful

  369. Simply , it is wonderful says:

    Thanks a lot author.

  370. Vijaya Sreenivas says:

    Freshers go through it & enjoy the concepts….

  371. Vijaya Sreenivas says:

    Exactly this entire page gives us clear knowledge on SDLC model. If u need basic knowledge go through it…..

  372. scywaulcher says:

    the way you explain concepts is good , you should consider writing more books and articles :) .

  373. Jaya says:

    It’s very helpful to me.Thanks a lot

  374. Jaya says:

    Very Nice!

  375. Venkat Raja says:

    Very nice article, you have the gift of putting it in simple terms. Thank you for sharing it.
    A few questions ………
    Could you please add examples of risks in the softwre context ?
    Also can you give examples of requirements changing midstream?
    How come they are so?

  376. Daffodil says:

    Thanks so much for such a comprehensive explanation of the SDLC models – Nice overview.

  377. How many life cycle models are applied now a day? The models waterfall and spiral are nolonger used, are they?

    I’m a new project manager so I need alot of project management information. I would like you reply my answer to my email box

  378. pavithra H A says:

    GOOD ONE!!
    its really helpfull

  379. rlewallen says:


    Try googling for “v-shaped life cycle”, or some variation thereof.

  380. rlewallen says:

    Angela, that would be Microsoft “Most Valuable Profressional”.

  381. Pratichi says:

    this is eally very nice and helped me in doing the analysis of my project.

  382. angela says:

    what does MVP stands fo in ur name. is it Master of Various Platforms :)

  383. Poonam says:

    good article. But i hav never seen a v-shaped life cyle model. where can i get details of this model?

  384. Diya Trivedi says:

    Hi, In lot of interviews iam asked if iam aware of X model or Y model along with V model. Is there something like X model and Y model for SCDL?

  385. rizwana says:

    hey…this comparision really helped me to understand wot i shud choose for my project…also include rapid prototype model,exteme prgrammig,code n fix and synchronize-stabalize models….thank ya

  386. rizwana says:

    hey…this comparision really helped me to understand wot i shud choose for my project…also include rapid prototype model,exteme prgrammig,code n fix and synchronize-stabalize models….thank ya

  387. Rizwana says:

    hey…this comparision really helped me to understand wot i shud choose for my project…also include rapid prototype model,exteme prgrammig,code n fix and synchronize-stabalize models….thank ya

  388. Rizwana says:

    hey…this comparision really helped me to understand wot i shud choose for my project…also include rapid prototype model,exteme prgrammig,code n fix and synchronize-stabalize models….thank ya

  389. sathish says:

    gud one for beginners !!!!!

  390. Laszlo says:

    Hello all,
    I can say Scrum is definitely making headway with a number of Fortune 500 / Global 1,000 companies embracing the values of the and the

    I dug up Kane Mar’s article on staggered iterative waterfall, part1 and part 2 here; I think it is relevant to the discussion:

    Best of luck on your projects.

  391. soul says:

    great work man, keep it up.

  392. zorina - trinidad says:

    hi just wanted to say that I had an assignment that required this information, and your explanation was so simple to understand, this was research we had to do, and I was able to write my assingment better because of you, thanks!!!
    ps. yes I didn’t plagerise, I sourced the info

  393. Kiran says:

    hi Ray
    Really its helping alot for who want to know SDLC life cycles.
    But wats the difference b/w Extreme programming and other models????
    Thanks in advance

  394. Gerard White says:

    I’m working on a project where we’re delivering iterations of the product in phases over four years (one per year).
    For our Software Development Plan (SDP), I’m trying to explain how to ensure overlapping test and design phases (test from previous – and design of next phase) don’t lose any changes.
    Anyone know of a good document I can check out and/or reference?


    – Gerry

  395. Kishore says:

    thanks for ur brief introduction abt SDLC Models.
    But i love to see more about V and waterfall models and it’s differences and most commonly used model now a days in industries?.
    It will be better and very usefull for begineers.

    thanking u

    kishore kumar

  396. Kunal says:

    Brilliant description

  397. Learner says:

    I would like more in detail about the differences between high-level design and low-level design. Where can I find them?

    Thanks in advance

  398. Gopi says:

    Nice and very good Jurney about SDLC

  399. Abdi somali says:

    thanks for doing my coursework for me maan this is what i needed

  400. o says:


  401. surekha says:

    Good one,I’am preparing for my interview and this is what i was looking for. Very simple but explains every thing. Thank you.

  402. Sunil says:

    Good one!

  403. Beverly says:

    This article help me a great deal in my project on sdlc models and am just saying thankyou.

  404. navaneeth says:

    it good

  405. ioajgfw says:

    umechemsha v shped model haipo vile kabisaaa!

  406. Adi says:

    Nice Summary!… Add something about RUP!


  407. kiran says:

    very good stuff. wants v-model in details. thaks for stuff

  408. rlewallen says:

    SCRUM is not a super common model, although its certainly going to be in the near future, like many agile models. SCRUM is an incremental/iterative model combination. These types of models are making serious headway into mainstream development and are used by more and more teams everyday.

  409. amrita says:

    hey this is good one but what abt new type model scrum used by microsoft mention nothing abt it

  410. kiruba says:

    good one

  411. Geo says:

    Good explanation on models. all people have contributed well to this topic.

    Could you tell which model suits a product development project in which the resource skill set is low on ; a new tecnology area ; and technical aspects of development is unaware.

  412. Madhavi.s says:

    good information regarding the models.can u explain which would be more useful for small projects and big projects.

  413. Cuckoo says:

    Raymond, very well explained in a concised manner !! Looking forward to some more comparisons.

  414. muhdiin says:

    compaire between prototype model and linear sequential model

  415. aish says:

    i get all knowledge abt software development life cycle that iwant thanks for your knowledge

  416. swetha says:

    Good one. This is what looking for. Explained in simple text with good pictorial representation. Thanks.

  417. Prakash says:

    Good one. This is what looking for. Explained in simple text with good pictorial representation. Thanks.

  418. Gonzalo,

    The XP methodology of software design explains it very well because its an agile model that adapts to change easily. I would start here:

    to answer your specific questions, and then read through more of the information that you find on the site. That will give you a better view of the approach I support concerning the iterative + incremental SDLC.

  419. Gonzalo Espert, Argentina says:

    Thanks Ray for your clarification.

    In that case, which would be the diference between the requirement phase of the first iteration and the following ones? If you are only refining the requirements wouldn’t you be re-working iteration after iteration? On the other hand, how do you carry the planing phase if you don’t know what would come up in the requirement phase of each iteration?

    Note that I’m not saying that your approach is incorrect. I’m trying to understand your incremental model more thoroughly.

    Kind regards.

  420. Gonzalo,

    All SDLC’s have variations to them, and you have stated a variation that McConnell’s opinion is that is a better incremental model. I disagree with his assertion, as you cannot design completely upfront in and in one single phase because its a losing battle. Those requirements and design are going to change, so attempting to do it all at once is a futile process.

  421. Gonzalo Espert, Argentina says:

    I would like to note that according to McConnell’s “Rapid development” book and also “Quality Software Project Manajement” from Software Quality Institute Series, the incremental development life cycle model does not imply that each iteration passes through the requirements, design, implementation and testing phases. They both state that each iteration passes through detailed design, implementation and testing phases. Thus requirements and high level design is done once at the begining.


  422. Gurp,

    Glad it turned out to be so useful for you! Congrats on your interview and good luck with your job.

  423. Gurpratap says:

    this article helps me to crack my interview and i am very thankful to the person who has written such a easy to understand article.

  424. Nigel says:

    Many thanks for this excellent overview! Very helpful for an Assignment i have to write. Thanks a lot for the post.

  425. King says:

    thanks very much for ur post

  426. Eddy, I wrote the article and made the nifty little pics. Credit Raymond Lewallen in your bibliography.

  427. Eddy says:

    Who wrote this artical? if possible to use the pictures, i would like to give credit to the author within my biblography.

  428. Akshatha says:

    This was very informative. In simple words, you explained a lot

  429. Adam says:

    Thanks for sharing this with everyone, it really helped me explain system life cycles on my Computing course at uni.

    p.s. would it be possible for me to use those diagrams?



  430. Louise says:

    whats the difference between a spiral model and a waterfall model

  431. Kunal Aggarwal says:

    Hello firends,
    I am facing major problem in deciding SDLC for my project.
    It is already in ASp I want to Convert it in ASP.NET and C#.
    Please send me your choice and supported reasons for that.

    With regards
    Kunal Aggarwal

  432. Irwin says:

    I loved this article, it was a great source for my Computer Science cource. Thanks so much!

    Ofcource I sited my resources. :)

  433. Santosh Kale says:


    This is a kind of article i was looking for, thanks for sharing it with all. This would help in understanding the different SDLC models.

    Thanks & Regards,
    Santosh Kale

  434. Mithun says:

    This is a very Good Article That would help to understand Different SDLC Models.

  435. Ganesh says:

    Hi Ray,
    This is really a cool and an informative piece of information on sdlc models.

  436. For the incremental picture, you might want to indicate there are multiple incremental flows.

    Great overview!

  437. Steve Hebert says:

    I guess I’ve never seen the V-shaped testing model as an SDLC – but your picture changes the testing model blocks and is interesting. I wonder if High-Level Design should be mapped to Acceptance Testing, Low-Level (Use Case?) to Integration Testing and then break out the Implementation into 3 blocks (Unit Test Design) -> (Implementation) -> (Unit Test Execution). That’s a fairly decent picture to how TDD fits in the picture. :)

    You might want to look at the models called out in Rapid Development: these include Code/Fix, waterfall, staged delivery, design to schedule, evolutionary prototyping, evolutionary delivery, modified waterfall (sashimi), spiral, RUP and Agile. Agile wasn’t listed in the book, but I blogged about Construx’ discussion of it (Construx is owned by McConnell):


  438. Jeremy says:

    XP is iterative *and* incremental (like RUP and essentially all modern processes). Barry Boehm’s old spiral model is only iterative. It’s actually a significant difference.

  439. sahilmalik says:

    Hey Ray,

    This is a good post, but for some reason it isn’t appearing in aggregators.

    Secondly, isn’t extreme programming very similar to the spiral model? Just a few new bells whistles and buzz words !!!

    – SM

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