From 5a12e7c134274dba706667107d10d231517d3e05 Mon Sep 17 00:00:00 2001 From: Patrick J Volkerding Date: Wed, 26 Aug 2009 10:00:38 -0500 Subject: Slackware 13.0 Wed Aug 26 10:00:38 CDT 2009 Slackware 13.0 x86_64 is released as stable! Thanks to everyone who helped make this release possible -- see the RELEASE_NOTES for the credits. The ISOs are off to the replicator. This time it will be a 6 CD-ROM 32-bit set and a dual-sided 32-bit/64-bit x86/x86_64 DVD. We're taking pre-orders now at store.slackware.com. Please consider picking up a copy to help support the project. Once again, thanks to the entire Slackware community for all the help testing and fixing things and offering suggestions during this development cycle. As always, have fun and enjoy! -P. --- README.initrd | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 README.initrd (limited to 'README.initrd') diff --git a/README.initrd b/README.initrd new file mode 100644 index 00000000..20ec4054 --- /dev/null +++ b/README.initrd @@ -0,0 +1,100 @@ + +Slackware initrd mini HOWTO +by Patrick Volkerding, volkerdi@slackware.com +Sun Jul 12 23:23:24 CDT 2009 + +This document describes how to create and install an initrd, which may be +required to use the 2.6 kernel. Also see "man mkinitrd". + +1. What is an initrd? +2. Why to I need an initrd? +3. How do I build the initrd? +4. Now that I've built an initrd, how do I use it? + + +1. What is an initrd? + +Initrd stands for "initial ramdisk". An initial ramdisk is a very small +Linux filesystem that is loaded into RAM and mounted as the kernel boots, +and before the main root filesystem is mounted. + +2. Why do I need an initrd? + +The usual reason to use an initrd is because you need to load kernel +modules before mounting the root partition. Usually these modules are +required to support the filesystem used by the root partition (ext3, +reiserfs, xfs), or perhaps the controller that the hard drive is attached +to (SCSI, RAID, etc). Essentially, there are so many different options +available in modern Linux kernels that it isn't practical to try to ship +many different kernels to try to cover everyone's needs. It's a lot more +flexible to ship a generic kernel and a set of kernel modules for it. + +3. How do I build the initrd? + +The easiest way to make the initrd is to use the mkinitrd script included +in Slackware's mkinitrd package. We'll walk through the process of +upgrading to the generic 2.6.29.6 Linux kernel using the packages +found in Slackware's slackware/a/ directory. + +First, make sure the kernel, kernel modules, and mkinitrd package are +installed (the current version numbers might be a little different, so +this is just an example): + + installpkg kernel-generic-2.6.29.6-i686-2.txz + installpkg kernel-modules-2.6.29.6-i686-2.txz + installpkg mkinitrd-1.3.4-i486-3.txz + +Change into the /boot directory: + + cd /boot + +Now you'll want to run "mkinitrd". I'm using reiserfs for my root +filesystem, and since it's an IDE system the reiserfs module will be +the only one I need to load: + + mkinitrd -c -k 2.6.29.6 -m reiserfs + +This should do two things. First, it will create a directory +/boot/initrd-tree containing the initrd's filesystem. Then it will +create an initrd (/boot/initrd.gz) from this tree. If you wanted to, +you could make some additional changes in /boot/initrd-tree/ and +then run mkinitrd again without options to rebuild the image. That's +optional, though, and only advanced users will need to think about that. + +Here's another example: Build an initrd image using Linux 2.6.29.6 +kernel modules for a system with an ext3 root partition on /dev/hdb3. +Note that you need the mbcache, jbd, and ext3 modules to use ext3: + + mkinitrd -c -k 2.6.29.6 -m mbcache:jbd:ext3 -f ext3 -r /dev/hdb3 + + +4. Now that I've built an initrd, how do I use it? + +Now that you've got an initrd (/boot/initrd.gz), you'll want to load +it along with the kernel at boot time. If you use LILO for your boot +loader you'll need to edit /etc/lilo.conf and add a line to load the +initrd. Here's an example section of lilo.conf showing how this is +done: + +# Linux bootable partition config begins +image = /boot/vmlinuz-generic-2.6.29.6 + initrd = /boot/initrd.gz + root = /dev/hda6 + label = Lnx26296 + read-only +# Linux bootable partition config ends + +The initrd is loaded by the "initrd = /boot/initrd.gz" line. +Just add the line right below the line for the kernel image you use. +Save the file, and then run LILO again ('lilo' at the command line). +You'll need to run lilo every time you edit lilo.conf or rebuild the +initrd. + +Other bootloaders such as syslinux also support the use of an initrd. +See the documentation for those programs for details on using an +initrd with them. + + +--------- + +Have fun! -- cgit v1.2.3