Re(2): [SunRescue] a bit OT but...

[Tim Hauber]

rescue at sunhelp.org writes:
>
>Didn't I hear somewhere that you don't 'need' to reboot to upgrade to
>Solaris 8?  Or am I wrong?
>
>-Jonathan

Oh goody!, someone invented a kernel that can hand off running processes. 
Somehow I think that if this is true then someone has re-defined the term
"reboot"  As far as I know any changes that require replacing or changing
the kernel always require a reboot, because the kernel lives in memory. 
 I suppose someone could invent a method of changing the kernel while it
ran, but it would be an academic exercise on an extremely lightly loaded
machine, and I imagine the code to monitor exactly where the kernel was
executing at a given moment in time would require breakpoints built into
the kernel itself, so you might as well just shut it down and upgrade it. 
The trend in Linux toward dynamically loaded modules may at some point be
utilized to make a very upgradeable while running system, but uptimes
really aren't that big a deal anyway.  uptime before the machine has to be
brought down, or crashes, is important, and this is the Windows weakness.  
I don't feel a reboot for upgrade in any way besmirches the quality of the
machine or the admin.  I mean, a machine with a year+ uptime, of course
you are sentimentally attached to it, and proud of it, but if the machine
needs to do something more than what the installed OS can do, record your
uptime for posterity, and shut it down.  In a growing system things like
memory very likely need to be upgraded, and in all but the very largest
configurations that requires a full powerdown.  In smaller systems,
running IDE disks, even disk upgrades need a powerdown.  Besides, isn't it
some of the Solaris versions that the uptime buffer rolls over and
restarts at 0?

By the way, I am just killing time waiting to see if a mailserver with max
uptimes in the single digit days is going to stay up, and at the moment
I'd rather see my fileserver which is pushing 200 days or better go down,
because if the mailserver doesn't stay up, I can't go home.

Of course, that fileserver is only a kinda *ix, it's MacOSX, and the
mailserver is MacOS8.1, and a fresh upgrade at that, so you can't expect
too much.  Before the upgrade we were getting a few months for uptimes,
still better than a lot of NT machines.