an OS question

[cellio]

While waiting for assorted software updates to install today I found myself wondering... Mac OS and Windows usually need to reboot your machine to install updates. Yet I have, several times, seen Unix machines that I believe were being maintained with uptimes of more than a year. What's the deal? Is Unix just better able to support hot-fixes, or are Unix updates that rare? (Or am I wrong about the maintenance of those machines?) And if it's that Unix is better at updating, why does Mac OS, which is Unix-based, need to reboot so often? Mind, it's definitely better in this regard than when I was running Windows; this is a puzzle, not a rant.

Edit: Thanks for the comments thus far. I now understand more about how Unix is put together, and why Windows is different. Still not sure about Mac OS but comments suggest it could be UI-related (that is, the GUI might be more tied into the OS than is the case on Unix).

Comments

[cellio]

Oh! I hadn't made the connection about inodes, even though (1) I know what they are and (2) I've been frustrated by that complaint from Windows that some (unnamed, mysterious) process is using a file I want to delete. Yeah, that makes sense!

I'm currently on XP at work, though I understand that Windows 7 will be rolling out next year. I should be good until October, when the lease on my current machine expires, assuming nothing melts down that would require earlier replacement. (My goal is to be among the last to get it, not among the first. That's not specific to Windows 7; for any expensive transition, I want to be able to benefit from what others have learned, 'cause my deadlines aren't going to get pushed out just because I now have to figure out accessibility, security, and just plain usability in a new environment.)