Microsoft programmers: what are they doing all day?

By aaron.axvig, 23 March, 2007

According to this Wikipedia article, Windows Vista Beta 2 had 50 million lines or code, or about 10 million more than Windows XP.  That seems like a lot, right?  Well, take a look at these calculations:

Say there were 15 million lines of code added for the final version of Vista (I doubt many more than a million were added between Beta 2 and RTM, but I'll be generous).  Then say that they had 4 years to work on it, working 200 days each year (again, being quite generous with the numbers).  So 15,000,000/(200*4) = 18750 lines of code per day.  That seems like a lot.

But lets consider: Microsoft employs at least 60,000 people.  Let's again be generous and say just 1000 of those were actually writing code daily.  Do some division and you get each of those 1000 coders writing just 18.75 lines of code per working day.

What were those employees doing the rest of the day?  Here are my ideas:

  • Figuring out how to merge their source with everyone else's.  I suppose it is no small task to combine 15 million lines of source code from 1000 or more different programmers.
  • Planning features.  However, I suspect that there were several thousands of other employees doing this and other things like testing and graphical design.  I think my guess of 1000 coders should be somewhat close to how many people Microsoft had programming on their flagship product.
  • Quality control.  Microsoft does have their initiative to write super secure applications; maybe this takes a lot of effort.  I suppose if you write enough unit tests....

I would love to see some holes poked in these numbers or find a really good excuse.  Seriously, less than 19 lines of code per day?