Pingdom AB , a Swedish-based website monitoring firm, recently studied the uptime of the update sites for the three most popular desktop operating systems, Microsoft, Apple, and Ubuntu. During the second quarter of 2008 (April-June), Pingdom reports that Windows Update was up 100% of the time, compared to Apple Software Update's 99.9% uptime, and Ubuntu Archive's 98.64% availability. During the period, Apple's update service could not be contacted for a total of 2 hours, 34 minutes, while Ubuntu's update service could not be contacted for a total of 1 day, 5 hours, and 45 minutes.
In the comments section of the Pingdom report , a number of Ubuntu users point out that only the main Ubuntu Archive was monitored, not its mirrors, and that Ubuntu's archives are used for application distribution as well as operating system files. Meanwhile, Windows users note that you don't need to select a different mirror to get an update from Microsoft - Microsoft transparently switches to different servers as needed.
How about it, Microsofties? Did you have problems in April-June getting to Windows Update? Ubutuites, speak up. Was Archive out to lunch when you needed an update? And Apple fans, how's your experience with Apple's Software Update? Tell us about your experiences.