Re: usb bootable stick

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



What of the device firmware, boot capability contained therein, performance optimization contained in the section between the front of the drive and the start of the provided partition, and and crazy often auto-mount firmware “CD-ROM” provided as a method of device software availability and possible auto-installation in Windows systems set up to do so?


On Fri, Oct 16, 2015 at 9:43 AM, Rick Stevens <ricks@xxxxxxxxxxxxxx> wrote:
On 10/16/2015 02:36 AM, Ranjan Maitra wrote:
On Thu, 15 Oct 2015 22:44:20 -0700 Joe Zeff <joe@xxxxxxx> wrote:

On 10/15/2015 09:14 PM, Ranjan Maitra wrote:
No, I would not think so. But if the device is not mounted, would it not write to the mount point, especially because you are doing so as root (so nothing to stop you). This logic seems to make sense to me, and indeed is what happens when I have done it accidentally (without mounting the USB drive).

If the device isn't mounted, there's no mount point for the command to
write to.

Correct. Then where would it write to?

If you write to a /dev/sd* node, you write to the raw device whether
it's mounted or not. If that device happens to be mounted at the time,
then things are going to get very ugly with the mountpoint as the
filesystem associated with the mountpoint won't necessarily know about
what you've done to the underlying device--the filesystem's idea of
what's on the device will be different than what's actually on the
device. Some programs do take care to not permit you to write to a
raw device if it's mounted to keep this from happening.

Mountpoints are just directories. If you write to the mountpoint
_without_ any device being mounted there, then you write into the
mountpoint directory as you would any directory. If you then mount a
device at that spot, the contents of the device will hide the content
existing in that mountpoint directory until you unmount the device.
Then the content you wrote to that directory will reappear.

In general, if the target of some operation is a node in /dev then do
try to ensure it (or any part of it) is _not_ mounted. One of the
easiest ways is to use "mount | grep <device>", e.g.

        mount | grep /dev/sdb

If you don't get any output, then you can be relatively sure that no
part of the physical device /dev/sdb is being used as a filesystem.
----------------------------------------------------------------------
- Rick Stevens, Systems Engineer, AllDigital    ricks@xxxxxxxxxxxxxx -
- AIM/Skype: therps2        ICQ: 226437340           Yahoo: origrps2 -
-                                                                    -
-         "OK, so you're a Ph.D. Just don't TOUCH anything!"         -
----------------------------------------------------------------------

--
users mailing list
users@xxxxxxxxxxxxxxxxxxxxxxx
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

-- 
users mailing list
users@xxxxxxxxxxxxxxxxxxxxxxx
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org
[Index of Archives]     [Older Fedora Users]     [Fedora Announce]     [Fedora Package Announce]     [EPEL Announce]     [EPEL Devel]     [Fedora Magazine]     [Fedora Summer Coding]     [Fedora Laptop]     [Fedora Cloud]     [Fedora Advisory Board]     [Fedora Education]     [Fedora Security]     [Fedora Scitech]     [Fedora Robotics]     [Fedora Infrastructure]     [Fedora Websites]     [Anaconda Devel]     [Fedora Devel Java]     [Fedora Desktop]     [Fedora Fonts]     [Fedora Marketing]     [Fedora Management Tools]     [Fedora Mentors]     [Fedora Package Review]     [Fedora R Devel]     [Fedora PHP Devel]     [Kickstart]     [Fedora Music]     [Fedora Packaging]     [Fedora SELinux]     [Fedora Legal]     [Fedora Kernel]     [Fedora OCaml]     [Coolkey]     [Virtualization Tools]     [ET Management Tools]     [Yum Users]     [Yosemite News]     [Gnome Users]     [KDE Users]     [Fedora Art]     [Fedora Docs]     [Fedora Sparc]     [Libvirt Users]     [Fedora ARM]

  Powered by Linux