Monday, 8 September 2008

Iterative and Agile - the Venn Diagram of truth

I'm seeing a bit of this lately:

"Iterative software development is Agile software development."

and I have to say that I disagree quite strongly. The Venn diagram actually looks more like this:


This post has been prompted by two things. First, a few weeks ago a SCRUMmer made some comments along the following lines:
  • "We don't allow changing the iteration plan once the iteration has begun" 
  • "All the requirements for the stories for the iteration must have been gathered before it starts."
  • "If the customer want something else, they have to wait for the next iteration"
And some articles/blogs about iteration lengths that jogged my memory about what I disagreed with. The root of my discomfort in equating iterative development to agile development is because

agile software development is a set of values, it is not a process. 

In fact, one of the core values of Agile development is to not value you process too much. There are some processes that try to embody Agile values, and they have different interpretations and practicalities around those values, but these processes are not what defines Agile development. 

Here's a reminder of what it means to be agile:
  • Individuals and interactions over processes and tools 
  • Working software over comprehensive documentation 
  • Customer collaboration over contract negotiation 
  • Responding to change over following a plan 
It's very possible to do iterative development without embodying any of these values. Treating each iteration like a waterfall with the usual waterfall suspects (requirements up front, little room for manoevering, opressive specification and documentation) is a case in point. And to me, valuing your plan over your customer by not responding to their needs is not Agile.

You are, of course, invited to disagree...

Wednesday, 3 September 2008

Me and my dog on Google Chrome

Like every man and his dog I feel compelled to say something about Chrome, Google's new browser. Most impressions I have read have been favourable, and my personal experience so far is very positive. Most reviews I have scanned have been thumbs-up, and have focussed on the usual suspects, i.e. rendering and javascript performance, stability, usability etc. etc.

For me, there is something subtle and extremely powerful that comes with Chrome. It fields a combination of features with very powerful implications. A "whole being more that the sum of the parts" kind of situation.

In the past year or two there has been a lot of focus in the "richer" web experience, and on ways of getting the web to feel more like the desktop. Newish technologies like Flex and Silverlight have received significant attention, and DHTML (Javascript+CSS+DOM+HTML) seems to have become the cousin that you are obliged to invite to your wedding party (or application party), but don't really want to. I believe that part of the reason for this has been Javascript performance, but there are several efforts underway (e.g. TraceMonkey and now Chrome's V8 Javascript engine) that will bring huge leaps in performance to Javascript. Also, I prefer to support non-proprietary technologies such as DHTML over vendor-based alternatives like Flex and Silverlight.

The second feature that's important in Chrome is process isolation for tabs. This enables each tab to be completely isolated from other processes. One tab going down doesn't take the whole browser with it (which is something that has plagued my Firefox quite a bit).

Thirdly, we have "application-like" OS integration in Chrome. Chrome has the ability to make a single tab look like an application window, with normal window decorations:


In your taskbar it looks like an application, there is  quick lauch icon for you app:

There's also a Start Menu item (not shown) and a Desktop icon:


The combination of these three is a significant step towards blurring the lines between the desktop and the web. Chrome is an application platform with (potentially) desktop-like application performance (DHTML + V8), process isolation (a key feaure of an application platform) and the web apps look like desktop apps (Operating system integration). And it's all standards based.

There have been some rumours of a Google OS...

You're looking at it.