This is just a general question - I was sitting and waiting for a bit of software to compile (we use Incredibuild here but can still take 10/15 mins) and it got me wondering, does anyone know how long it took to compile Windows XP or Vista?
I did some googling but didn't really find any useful information
OP is asking about Windows:
"There are no other software projects like this," Lucovsky said, "but the one thing that's remained constant [over the years] is how long it takes to build [Windows]. No matter which generation of the product, it takes 12 hours to compile and link the system." Even with the increase in processing horsepower over the years, Windows has grown to match, and the development process has become far more sophisticated, so that Microsoft does more code analysis as part of the daily build. "The CPUs in the build lab are pegged constantly for 12 hours," he said. "We've adapted the process since Windows 2000. Now, we decompose the source [code] tree into independent source trees, and use a new build environment. It's a multi-machine environment that lets us turn the crank faster. But because of all the new code analysis, it still takes 12 hours."
Also see Mark Lucovsky classic presentation on developing Windows NT/2000.
I don't work at Microsoft, so I don't know for sure...