The Third Version Is Charmed

Claimer: I first posted this information on ThirdSystemEffect, but what I was trying to say was ThirdVersionEffect. That name is too similar to the SecondSystemEffect by FredBrooks. If you feel like this is a better name, we can keep it. -- GuillermoSchwarz

The first version of any software usually works but is a big mess inside. Most functionality has been postponed, that's why they were able to deliver in the first place.

If your project is in its second version, it will be better.

When your project is finally the third version, then it will probably succeed in a clean elegant way, because you will have GetTheRightAbstraction.

Since the first version is successful, they decide to create a second version. The second version, to be successful, needs a lot of refactoring and some rewrite to GetTheRightAbstraction. The right abstraction is the abstraction that permits to easily add the much needed new functionality.

The same happens with the second version: It is better than the first one, but only so much better. A third version is needed. This time, there is more refactoring and more code written from scratch. You GetTheRightAbstraction this time, because you have so much hindsight. The third version usually is easier to understand to its developers, but not as easily understood by new developers: they would have preferred the first version because they have no hindsight. You can't skip the earlier versions - they are required to get hindsight. You must really try hard to get the first and the second version to work, get released and used. You must get feedback from them, then you can go on to implement the third. Is it possible that the MythicalManMonth has been replaced in practice by the MythicalManHour???

Originally written by GuillermoSchwarz

The first version of any software usually works but is a big mess inside. Most functionality has been postponed, that's why they were able to deliver in the first place.

When your project reaches the third version, it will probably succeed in a clean elegant way.

Since the first version is successful, they decide to create a second version. The second version, to be successful, needs a lot of refactoring and some rewrite to GetTheRightAbstraction. The right abstraction is the abstraction that allows the much needed new functionality to be added easily.

The same happens with the second version: It is better than the first one, but only so much better. A third version is needed. This time, there is more refactoring and more code written from scratch. You GetTheRightAbstraction this time, because you have so much hindsight. The third version is usually easier to understand by its developers, but not as easily understood by new developers: they would have preferred the first version because they have no hindsight. You can't skip the earlier versions - they are required to get hindsight. You must really try hard to get the first and the second version to work, get released and used. You must get feedback from them, then you can go on to implement the third.

This is not related to the SecondSystemEffect, discussed by FredBrooks in The MythicalManMonth. Roughly the SecondSystemEffect says: If your project is the second unrelated system for most of your designers, it will probably fail outright, because your designers feel confident and therefore they are not careful enough. If it doesn't fail, it will be bloated, inefficient, and icky.

Not quite:

: "An architect's first work is apt to be spare and clean. He knows he doesn't know what he's doing, so he does it carefully and with great restraint."
: "As he designs the first work, frill after frill and embellishment after emellishment occur to him. These get stored away to be used 'next time.' Sooner or later the first system is finished, and the architect, with firm confidence and a demonstrated mastery of that class of systems, is ready to build a second system." [emphasis mine, MythicalManMonth pg55].

He goes on to describe the IBM 709 architecture, the 'second system' of the "very successful and clean 704" architecture. We're clearing talking about the same type of system, merely a new version of.

It's a different but related phenomenon to what you're describing.

--WilliamUnderwood

I agree. GreatMindsThinkAlike?. ;-) -- GuillermoSchwarz