This is one of the things I like most about Chrome OS and many newer Android devices (like Pixel phones): A/B updates.
Chrome OS keeps two full copies of the OS, one on the A partition and one on the B partition. When an update happens, it gets applied to the inactive partition, then the system sets a flag that switches which partition is the boot partition.
You update at that point by rebooting. The nice thing is that this happens naturally most of the time when you shut down the machine.
The biggest reason is profit with the pretext of security. That forced update fits better with the software as a service Microsoft is pushing for, and it minimises their support costs. The whole deployed user base is forced to a version which you want and they have no say whatsoever about it. You can push things they didn’t want like your new browser or the xbox core, or reset their privacy settings every week so they can’t stop you collecting their data. All that makes you or saves you money. Linux has been considerably more secure without forcing updates, and chrome os is doing it right by using a dual partition system, where the updates are applied after you reboot without forcing you to do it mid work. This was a business decision not an engineering one
The reality is that there must be a critical patch needing to be applied that without, could result in such things as ransomware, or compromised system for remote access/botnet, etc.
IIRC, almost all Intel CPUs now have a flaw that, well, can’t be fixed (vulnerable during bootup).
Honestly, most people feel entitled to own a computing device because they feel the need, or are provided one from work with expectation that it will be updated. But its ignorance here, not stupidity (they know how to surf the web and buy stuff..), that results in mass infection. Just like real-world pandemic, there will always be some that ignore the rules/law/procedures because they don’t “apply”.
So computers will update and need to restart. Also its not like they didn’t warn you- and if you are ignoring the warning, its going to happen. Or not, and by then, too late.
Because otherwise people will never run the updates. If left to their own devices, the average computer use will assume they’re fine because updates are an incredibly opaque and abstract subject. Those leaves those users open to security vulnerabilities and delays the adoption of new features.
Some people assume they don’t need the updates because they don’t visit certain types of website, or because they don’t engage in whatever risky activity, while other people assume that what they have now is good enough and running updates is just going to interrupt their flow.
In short: people are lazy, and wildly overestimate their current level of safety while wildly underestimating their risk.
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