Recently I was surprised by how long Windows Update took to simply decide which updates were available. When rejuvenating a relative's Vista machine that hadn't been online for about 6 years, it took WU more than 2 days of fully pegging the CPU to finally deliver the news that ~200 updates were available.
What was it doing all that time? Some kind of solver?
About a month ago I decided to reinstall Windows on one of my old PCs, an Intel Ivy Bridge desktop i5. It is frustrating and nearly impossible to end up with a patched system. The process was pretty much as follows:
1. Manually check for updates. This took forever and thrashed the hard disk, every time.
2. Select, download, and install the updates.
3. Goto 1 until Windows couldn't find any more updates.
In some cases, step 2 would fail with various unknown errors and hex codes. The only way to fix this is to run a Windows diagnostic that "resets Windows Update components", which makes Step 1 take even longer than it would have otherwise.
All in all, I think the update cycle took me about 4 hours before I gave up on the third reboot and decided to just let Windows figure itself out. Compare this to an 'apt-get update && apt-get upgrade' or the OS X Software Update, and it's a wonder people update Windows at all.
> Compare this to an 'apt-get update && apt-get upgrade' or the OS X Software Update
There was a major update to Arch recently - due to GCC 5 changing the standard C++ library with binary interface changes. Basically every package written in C++ and compiled with GCC needed re-compiling and updating.
Mine took about an hour to update (6 year old machine) - with over 500 packages updated. Of course everything kept running, but I chose to reboot since it was such a major change and everything worked flawlessly. Kudos to the whole Arch team.
But take a minute to think about that - it's a major percentage of the whole system updated.
Updating my Windows machines in comparison is terrible - the amount of time and effort is so variable, plus having to be careful to avoid or remove the dreaded tracking updates backported from Windows 10.
Even though I dnot use windows anymore, I have done this many many times with Windows Vista and Windows 7. It never took more than few hours. Even though few hours pretty freaking long. Taking couple of days doesn't sound like normal.
"Windows 7 uses Component-Based Servicing [1], which means Windows Update has to work ridiculously hard to determine file and component dependencies/inter-dependencies, maintain side-by-side versions of older files/components, while still making it possible to uninstall individual updates/components but without breaking any other updates/components, all the while taking into account supercedence and god knows what else. The code that does all this must be hellishly complex."
There was a brutal bug in Vista on some machines where it would peg the CPU for hours during update check on start-up. Users learned to never fully reset unless it was critical. I saw it personally in multiple machines, and I'm a dev not an admin - I only use a handful of computers.
Maybe there's a problem somewhere, because I've seen reports of other people being affected on various forums in October and November. I am currently trying to update a W7 SP1 VM, but it just keeps looking for updates, even after installing two updates for the update client itself.
It's extremely annoying and not related to Vista particularly, nor specific types of hardware as far as I can tell.
This is the thing that amazed me most when switching from Windows to Mac, no more endless updating and rebooting. Updates seem less frequent and also less time consuming.
I noticed the same thing you describe on Windows 7 by the way.
What was it doing all that time? Some kind of solver?