Re: Automounter in KDE
On Thursday 11 August 2005 02:19 pm, serja wrote:
> About multiuser OS theory I've read in suse faq:
> Q: why can't I simply remove the CD from drive without umount it first?
> A: because it's a multiuser OS and if you simply remove the CD without
> umounting it first the other users can't read it!
> ***
> Isn't it an excuse rather that theory? :)
> And whats happen if I umount it first and that remove? For other users the
> result will be the same. :)
SuSE is only giving you half the story. Even in a single-user environment,
you have to mount and unmount if you have write-behind caching[1] enabled,
which it is by default on all drives under Linux.
It's not unmounting that bothers me, though. It's mounting in the first
place. That has nada to do with single- vs. multi-user OS design, and
everything to do with kernel developers who haven't realized that the 70s are
over and not everything is either a fixed drive or badly-implemented network
share.
[1] Wire-behind caching is where the OS queues up stuff to write to disk, then
tells you that it's done before it actually is. It then gets to actually
writing the data out when it gets around to it, which may well be after
you've given it a dozen more write commands for the same disk, which overall
saves time. If the device disappears or the system crashes before it gets
around to it, though, you lose data. The "sync" command force-flushes all of
those caches for various disks, and journaling file systems are intended, in
part, to address the potential for badness when that happens.
--
Larry Garfield AIM: LOLG42
larry@garfieldtech.com ICQ: 6817012
"If nature has made any one thing less susceptible than all others of
exclusive property, it is the action of the thinking power called an idea,
which an individual may exclusively possess as long as he keeps it to
himself; but the moment it is divulged, it forces itself into the possession
of every one, and the receiver cannot dispossess himself of it." -- Thomas
Jefferson
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