Mageia 2 in live mode can't find usb

[shafagh]

magiea 2 in live mode can't found usb.why?
for solve problem :
1- we should put usb
2-restart
3- after restart magiea found usb( flash memory).
other distributions have not this problem.

[isadora]

Message moved to "Basic support", and title changed by moderator.

[doktor5000]

What USB devices did you try to connect? If you are in live mode, please do the following:
open a terminal, switch to root via

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su -

enter root password, then enter the following command

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tailf /var/log/messages

and now plugin the USB device that did not work, and post the resulting output here.

[gohlip]

If it can find the usb drive after a restart, it is most likely a bios issue, nothing to do with Mageia (livecd or installed).
You can verify this at grub (and really, grub has nothing to do with the OS too)
At mageia grub prompt (grub-legacy), type...

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grub> configfile (

and then press <tab> (you may have to press <tab> twice)
you will get an output of available drives/partitions, sometimes you see the usb drives, sometimes you don't; and if you see it, Mageia will definitely pick it up.
Also waiting a while will allow bios to pick it up. Note that in some older boots, the developers built in a "wait" (forgot what's it called, maybe usbwait or something like it) for usb boots.

If you are using the newer grub (grub2), at grub prompt, use

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grub> ls

(that's a small 'L', not 'one') to check the drive/partition.

[doktor5000]

As he is talking about normal operation in live mode, this has nothing to do with grub.

[gohlip]

As he is talking about normal operation in live mode, this has nothing to do with grub.

Precisely, no disagreement here.
What I am trying to show is that if bios does not detect his usb, no way Mageia will pick up that usb.
To show that, we can use grub commands to illustrate. If we use Mageia OS to show usb is not detected, it may still not prove that the cause is not Mageia's.
And grub has really nothing to do with Mageia, as you pointed out. So we are in agreement here, aren't we?

[doktor5000]

Sorry, this is plain wrong. What the BIOS sees, is only relevant for the boot process. If the kernel is taken over, BIOS is not relevant anymore.

[gohlip]

The bios maps out device drives and sometimes wrongly too (or none).
So when we have more than 1 drive, our hard disk which we think is sda can become sdb and that device notation is reflected in the OS itself (main reason we use UUID, not /dev/sdax for fstab, etc). Anyway, I couldn't find the link that explains all this, but here's 2 that can help somewhat.
http://www.gnu.org/software/grub/manual ... e-map.html
http://www.gnu.org/software/grub/manual ... e-map.html

And should I be mistaken about this, I will thank and celebrate the fact I have my mistake corrected, so I welcome and look forward to more information that could help in this direction.
Thanks in advance.
Cheers. - Goh Lip

ps: more... (but I still cannot find the one I'm looking for)

https://help.ubuntu.com/community/UsingUUID
"Linux now prefers to use UUID (Universally Unique Identifier), LABEL, or symlinks to identify media storage devices on a system. Directly using /dev/hd*# or /dev/sd*# is no longer preferred since these device assignments can change between system boots:"

https://wiki.archlinux.org/index.php/Fstab
"There are three ways to identify a partition or storage device in /etc/fstab: by its kernel name descriptor, label or UUID. The advantage of using UUIDs or labels is that they are not dependent on the disks order. This is useful if the storage device order in the BIOS is changed, or if you switch the storage device cabling. Also, sometimes the BIOS may occasionally change the order of storage devices."

and specifically about usb (rootdelay and waitusb) - but I think both are deprecated.
http://lwn.net/Articles/330378/