Making Good Software

A blog by Alberto G (Alberto Gutierrez)

Written by Alberto Gutierrez

July 23rd, 2009 at 7:22 am

Software development: Engineering or Craftsmanship?

with 3 comments

Wether Software development is an Engineering or a Craftsmanship is one of the hottest topics in the software development community, and it generates many articles and opinions as these two articles which have been brought to my attention lately and which I highly recommend you to read.

  • Tom DeMarco.  (Author of  Peopleware: Productive Projects and Teams)- Software Engineering: An Idea Whose Time Has Come and Gone? (PDF).  “My early metrics book, Controlling Software Projects: Management, Measurement, and Estimation (Prentice Hall/Yourdon Press, 1982), played a role in the way many budding software engineers quantified work and planned their projects. In my reflective mood, I’m wondering, was its advice correct at the time, is it still relevant, and do I still believe that metrics are a must for any successful software development effort? My answers are no, no, and no.” Saw in codinghorror.com
  • Charles Fishman. They Write the Right Stuff. (An article about the software developed by NASA).[…] This software never crashes. It never needs to be re-booted. This software is bug-free. It is perfect, […]each 420,000 lines long-had just one error each.[…]How do they write the right stuff? The answer is, it’s the process. […]The product is only as good as the plan for the product.

So who is right, Tom DeMarco, or the NASA, well, I wouldn’t dare contradicting any of them, I actually believe they both are right! What is wrong is the question: “Software development: Engineering or Craftsmanship?”. There isn’t an unique way to go, they can be both applied, is just a matter to identify which approach suits better to the software that has to be developed.

So… what approach to use in each case: Engineering or Craftsmanship?

Most commercial projects can’t simply cope with an Engineering approach, can you imaging building an e-commerce site that has to be fully specified and designed upfront with no changes after and without early feedback? I don’t think so, what is amazing is that there are still some companies that try to use an Engineering approach (most usually waterfall) to develop this kind of software. Waterfall only works if you follow all of  its steps and if you don’t make any change to the specifications when you start coding, when a waterfall project fails, most of the times is not because waterfall is wrong but because waterfall doesn’t adapt to the type of software they want to build, Waterfall doesn’t work with software that evolves while it’s been build, for these cases is better to follow a craftsmanship approach.

Craftsmanship approach characteristics

  • Specification and design are created in an on-going basis.
  • Gives plenty of  room for change.
  • Focus on people and communication.
  • Early feedback.
  • High rate of errors, but the application is functional.
  • Uncertainty on how the final product will be.

For some other companies what is essential is that there are no surprises and that the software doesn’t have any errors at all, that’s typical from critical systems as Aircraft software, Rocket software, Trains software… In this case an engineering approach is essential.

Engineering approach characteristics

  • It requires full specification and design beforehand.
  • Focus on processes and contracts.
  • It does not allow room for change.
  • Late feedback.
  • No surprises.
  • No errors (Almost).