takavoir

Quote: The Linux kernel on the boot disk, for some reason, will load the correct modules (drivers) to sense the usb drive, where the actual kernel and modules installed do not load the correct modules to see the drive and boot it correctly. That is why you need to alter the installed kernel with mkinitrd, which adds the modules you need to the actual installed kernel as the system boots. See this article to see what the situation is. I agree totally and this is what I understood but my question was: once Linux is correctly installed on the USB hard drive, why just booting from the install cd (without "linux rescue") is not enough to mount / ? Especially since we can see the installed partitions sda1 and sda2 with fdisk. Thanks again for your help anyway

Thanks a lot for all your explanations and help. It worked "like a charm" for me. I use: - laptop DELL D800 - external hard drive LACIE BIG disk 400GB USB 2.0 - GRUB installed on MBR of the USB hard drive - Choice of OS done from BIOS That little "linux rescue" made all the difference! I still don't get why I cannot mount / without "linux rescue" because I can see the partions with fdisk