hi:) At booting time ,bootloader loads kernel from hard disk too memory. During this period,does it need hd driver's support . thanks!
On Wed, 06 Feb 2013 02:53:11 +0800, horseriver said:
At booting time ,bootloader loads kernel from hard disk too memory. During this period,does it need hd driver's support .
Think for a bit - at that point, the hd driver hasn't been loaded yet, so it *can't* need the hd driver's support. So instead, the bootloader has a very dumb simplistic driver that's stripped down (for instance, no queued command support, one I/O in flight at a time, very little error handling, read operations only , etc etc) that's just enough to load the kernel and initrd. (There's often also a very stupid filesystem driver, just enough to read files. So for instance 'grub' can find the files for the kernel and initrd. Some bootloaders are too stupid for even that, and you have to run a special program to tell the boot loader where all the blocks of the file are (I'm looking at you, LILO :) Once the bootloader gets the kernel and initrd loaded, *then* the kernel can initialize the production driver with all the bells and whistles needed.
Thanks for your reply! After grub load kernel and initrd , it get around root filesystem mounting , but failed with no finding root device ,from which kernel and initrd have been located . ls /dev/ ; there is no disk device node . Why?
On Wed, 06 Feb 2013 05:37:41 +0800, horseriver said:
After grub load kernel and initrd , it get around root filesystem mounting , but failed with no finding root device ,from which kernel and initrd have been located .
ls /dev/ ; there is no disk device node .
Why?
Any number of possible reasons, anything from an improperly configured kernel, to a misbuilt initrd, to a root= parameter that points someplace broken, to....
On Wed, Feb 06, 2013 at 02:35:47AM -0500, Valdis.Kletnieks@vt.edu wrote:
On Wed, 06 Feb 2013 05:37:41 +0800, horseriver said:
After grub load kernel and initrd , it get around root filesystem mounting , but failed with no finding root device ,from which kernel and initrd have been located .
ls /dev/ ; there is no disk device node .
Why?
Any number of possible reasons, anything from an improperly configured kernel, to a misbuilt initrd, to a root= parameter that points
root = ? You mean the aasignment at grub command line ? thanks!
On Wed, 06 Feb 2013 12:30:37 +0800, horseriver said:
root = ? You mean the aasignment at grub command line ?
For instance, the grub entry for the kernel I'm running right now: title 3.8.0-rc6-next-20130206 kernel /vmlinuz-3.8.0-rc6-next-20130206 ro root=/dev/mapper/vg_blackice-root log_buf_len=2M vga=893 loglevel=4 thre adirqs intel_iommu=off LANG=en_US.UTF-8 initrd /initramfs-3.8.0-rc6-next-20130206.img (Strictly speaking, it's not the grub command line, it's the kernel command line that is passed to the kernel by grub or lilo or grub2 or syslinux or whatever boot loader happens to float your boat).
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