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Exponential Algorithm In Windows Update Slowing XP Machines

Posted by samzenpus on from the no-pep-in-your-step dept.

jones_supa writes "An interesting bug regarding update dependency calculation has been found in Windows XP. By design, machines using Windows Update retrieve patch information from Microsoft's update servers (or possibly WSUS in a company setting). That patch information contains information about each patch: what software it applies to and, critically, what historic patch or patches the current patch supersedes. Unfortunately, the Windows Update client components used an algorithm with exponential scaling when processing these lists. Each additional superseded patch would double the time taken to process the list. With the operating system now very old, those lists have grown long, sometimes to 40 or more items. On a new machine, that processing appeared to be almost instantaneous. It is now very slow. After starting the system, svchost.exe is chewing up the entire processor, sometimes for an hour or more at a time. Wait long enough after booting and the machine will eventually return to normalcy. Microsoft thought that it had this problem fixed in November's Patch Tuesday update after it culled the supersedence lists. That update didn't appear to fix the problem. The company thought that its December update would also provide a solution, with even more aggressive culling. That didn't seem to help either. For one reason or another, Microsoft's test scenarios for the patches didn't reflect the experience of real Windows XP machines."

4 of 413 comments (clear)

  1. Best way to force an upgrade by s_p_oneil · · Score: 4, Insightful

    That's the best way to force users to upgrade that I can think of. They're already planning to end-of-life it. After EOL, they can simply start adding empty patches to the update system until it drives left-over XP users to upgrade. ;-)

    1. Re:Best way to force an upgrade by mlts · · Score: 4, Insightful

      It killed my Web browsing virtual machine until I used an offline update utility and fixed it manually.

      Yes, XP needs to die, because it is made to deal with threats from 2000-2001, with added security patches strapped on as the need arose. Windows 7 and newer help address this issue.

      However, I know plenty of places where XP is used that can't be fixed by a upgrade or platform change. Embedded stuff for example. Another are dedicated machinery that interfaces with a PC, does have newer drivers, and likely will not get newer drivers. A friend's $3000 sewing machine is one example.

      Another person's CNC wood mill is another item. So, those machines are stuck with XP pretty much for good, because who is going to throw out a perfectly functioning mill just because it requires a legacy OS? Even some CD/DVD duplicators only will interface with XP, and moving to Vista or newer will be an exercise in futility.

      So, XP in a lot of cases is here to stay, for better or worse.

  2. Re:Remove, replace with apt by Anonymous Coward · · Score: 5, Insightful

    Yeah, four months before the final end of support date I'm sure they have a copious budget for massive rewrites on their three-major-versions-old legacy product.

    But good news: after next April, just kill off the update checker entirely, because there will never be an update again! Problem solved. You're welcome.

  3. Re:No Sympathy by viperidaenz · · Score: 4, Insightful

    So someone thought it was a good idea to upgrade a security system with software that will have no security support in 4 months time?