Gates was forced to rebuild Windows Vista
silicon.com | at | by Mike
Jim Allchin, group VP in charge of Windows, told the Wall Street Journal he dropped the bombshell last summer, simply telling Gates "It's not going to work". Longhorn was so complex that Microsoft's developers would never be able to make it run properly, Allchin told Gates.
The root of the problem was Microsoft's historical approach to developing software - the so-called 'spaghetti code culture' - where the company's thousands of programmers would each develop their own piece of code and it would then all be stitched together at the end.
The new approach was to develop a clean solid core code base for Windows which new features could more easily be added to over time and Allchin introduced new tools that would automatically reject buggy code.