J and I and Me
2012-05-08
  Common Misconceptions: The Waterfall Model
I think the Waterfall Model is the result of a big misunderstanding, probably one of the worst in out industry.
Look at Royce's original paper (PDF can be found here. You will notice that the paper starts with the separation of different activities such as analysis and coding. To me that sound like an attempt to actually define basic software engineering activities instead of just unstructured hacking. The paper goes on and discusses more different phases that a project might go through. It shows a figure pretty much like the Waterfall model we are used to. No surprises so far.
But then the fun starts: The third figure already shows that the steps are not necessarily performed in order. The text says:
... as each step progresses and the design is further detailed, there is an iteration with the preceding and succeeding steps but rarely with the more remote steps in the sequence.
Let me repeat: The original Waterfall paper says that you might need to go back to previous steps, even remote ones. It even uses the term "iteration".
It goes on and discusses that once you run in production you might learn that your system does not perform well enough. That leads to major problems - and you will probably go back to the analysis. You might call it an iterative approach - even though it is probably not voluntarily.
Even better: The paper suggests:
If the computer program in question is being developed for the first time, arrange matters so that the version finally delivered to the customer for operational deployment is actually the second version in so far as critical design / operations areas are concerned.
So essentially you should do at least two iterations - the first version will not get it right. Another hint at an iterative process.
And the paper even suggests to involve the customer - probably one of the most important points in Agile practices.
Of course the paper includes sections that are quite different from the Agile school - such as the focus on documentation. But it is from 1970 - and the author is specialized in systems for spacecrafts. Those still rely a lot on documentation even today because of the extreme risks those systems have.
However, the bottom line is that the original Waterfall paper does not advocate what is now considered the Waterfall Model. It does not require going through the steps in order and it even mentions that the first release will not be a good solutions. Quite contrarily: It talks about iterations - very limited of course but it hints the direction Agile and iterative processes took later on.
I am still confused how the industry was able to misunderstand this paper. I wonder how much damage it did. Even today people still talk about Waterfall. I think everyone working with software processes should read this paper. I also suggest to use the term "Misunderstood Waterfall Model" when discussing a model that suggest going through the steps in a strict order. Because that model is just a misunderstanding, it is not what Royce described.
Oh, and next time someone talks about the Waterfall Model - don't forget to ask him or her whether he has read the original paper about it...
  09:42 4 comments
Bookmark and Share
J for Java | I for Internet, iMac, iPod and iPad | Me for me

ARCHIVES
Juni 2005 / Juli 2005 / August 2005 / September 2005 / Oktober 2005 / November 2005 / Dezember 2005 / Januar 2006 / Februar 2006 / März 2006 / April 2006 / Mai 2006 / Juni 2006 / Juli 2006 / August 2006 / September 2006 / Oktober 2006 / November 2006 / Dezember 2006 / Januar 2007 / Februar 2007 / März 2007 / April 2007 / Mai 2007 / Juni 2007 / Juli 2007 / August 2007 / September 2007 / Oktober 2007 / November 2007 / Dezember 2007 / Januar 2008 / April 2008 / Mai 2008 / Juni 2008 / August 2008 / September 2008 / November 2008 / Januar 2009 / Februar 2009 / März 2009 / April 2009 / Mai 2009 / Juni 2009 / Juli 2009 / August 2009 / September 2009 / Oktober 2009 / November 2009 / Dezember 2009 / Januar 2010 / Februar 2010 / März 2010 / April 2010 / Mai 2010 / Juli 2010 / August 2010 / Oktober 2010 / Januar 2011 / Februar 2011 / März 2011 / April 2011 / Mai 2011 / Juni 2011 / August 2011 / September 2011 / November 2011 / Februar 2012 / April 2012 / Mai 2012 / April 2013 / Mai 2013 / Juni 2013 / Januar 2015 / Juli 2015 / Februar 2016 /

Links

Twitter
Google +
Slideshare
Prezi
XING
LinkedIn
Das Spring Buch


Feeds

Feedburner


Impressum
Betreiber und Kontakt:
Eberhard Wolff
Leobschützer Strasse 22
13125 Berlin
E-Mail-Adresse: eberhard.wolff@gmail.com

Verantwortlich für journalistisch-redaktionelle Inhalte:
Eberhard Wolff