Critical Path

A colleague of mine recently asked what I meant by "critical path." I gave her the following example, which she suggested I share:

Critical path is a project management term. It represents the longest running sequence of tasks required to complete a project.

For example, given the following tasks:

    • Task A takes 1 hour.
    • Task B takes 2 hours.
    • Task C takes 30 minutes.
    • Task D takes 45 minutes.

If the tasks must be completed in alphabetical order, then the critical path is A-B-C-D. And, the project will be complete in about 4.25 hours.

But, if you have a helper, and the tasks only need to start in alphabetical order, then the critical path is A-C-D. And, the project will be complete in about 2.25 hours. 

    • Elapsed Time 0:00 - You start task A. Your helper starts task B.
    • Elapsed Time 1:00 - You finish task A. You start task C
    • Elapsed Time 1:30 - You finish task C. You start task D.
    • Elapsed Time 2:00 - Your helper finishes task B.
    • Elapsed Time 2:15 - You finish task D.

But, what does an agile software developer need with an antiquated term like critical path? I was using it in the context of removing engineering work from a broader business process that could be completed faster if the other department involved could execute their tasks in parallel with engineering. So, there!


It’s 10:15pm. I woke up at 3:30am to catch my 6:15 flight to San Francisco. I should be in bed. But, I want to get something up on the blog about what’s going on.

For those of you who don’t know already, I accepted a software engineer position with last month. The job is in San Francisco. So, I’m traveling back and forth this month to help Jill with the move. I fly down Monday morning and home Thursday evening. It’s a bit frenetic. But, it’s worth it.

I’m too tired to write more right now. Suffice to say that I’m enjoying myself immensely and I’m learning an incredible amount of cool new stuff!


A garden's for life...

Portia Tung:

And no matter how much we try to hurry the seed along, Nature will run its course. Assigning ten gardeners won’t make the seed grow faster. In fact, fussing about with the seed could put it in peril.


As my father says, “A garden’s for life. And it needs you.” Given this commitment, it’s natural to want to make repetitive tasks, like weeding, as effective and efficient as possible so you have time to “grow” things.

I couldn’t have put it better myself.

Banishing the Inner Critic...

Denise Jacobs on A List Apart:

Why be concerned with your inner critic? In essence, an overactive inner critic acts as a deterrent between the seedlings of great ideas and the fruits of accomplishment. Don’t think you have an inner critic? Think again. The question is not if the troll is there, but rather how big, loud, and disarmingly influential and persuasive it is.

The article is targeted at web creatives. But, I think it’s equally applicable to my last post about courage. The inner critic is what you need the courage to overcome most of the time.

A lesson in courage...

Kent Beck in Extreme Programming Explained (first edition, page 31):

We will be successful when we have a style that celebrates a consistent set of values that serve both human and commercial needs: communication, simplicity, feedback, and courage.

Of all the agile values, courage is the one that doesn’t translate directly into specific practices. Communication is fostered by sitting together in an open space. Simple design pushes the simplicity meme, as does refactoring out duplication and YAGNI. And, feedback is built into the processes with things like Sprint Reviews and Retrospectives. But, courage? Which one of the practices embodies courage?

This is not a question I was asking myself. It wasn’t even on my mind until my test-obsessed friend and mentor, Elisabeth Hendrickson, offered to let me pair program with her on Entaggle this week. You see, Entaggle is written in Ruby using Rails, rSpec and Cucumber – tools I’ve never used. And, I have (as Elisabeth so delicately put it) “competence issues” – meaning that I have a fear of incompetence.

So, I was fairly aware that it was going to take some courage to overcome my fear of not knowing the tools in order to just sit next to Elisabeth in front of a keyboard. But, it wasn’t until we were sitting there and Elisabeth was muttering on about how she couldn’t believe she was showing me the code in such a sorry state – in need of multiple refactorings – that I realized that pairing with me took as much courage from Elisabeth as pairing with her took from me.

Suffice to say that the next time I sit down to pair program with someone, I’m going to be cognizant of the courage it took to bring both of us together with the code. I might even go so far as to recognize it before we begin pairing, just to get the fears out in the open so we can move past them.

I also think the next time I pair with Elisabeth, I’m going to muster the courage to write at least one test. (I can’t believe we didn’t write one!)