8.4. Installing a Kernel with Support for up to 4GB RAM and Multi-Processors
Due to the limited amount of space available on one CD, there is only one Linux kernel available on the Skolelinux/Debian-edu CD. So, the chosen Linux kernel is based on the lowest common denominator, which means that it should work on most kinds of hardware.
You can find out what kind of kernel you are running at the moment with the command uname -a, use this command later to verify that you have changed to a different kernel,if you choose to do so.
tjener:~# uname -a Linux tjener.intern 2.6.8-2-386 #1 Thu May 19 17:40:50 JST 2005 i686 GNU/LinuxIn this case I'm running a 386-kernel, which should work on just about any kind of PC, but it's not optimalized for dual processors or more ram than 940MB.
If you want a kernel for the newer servers with plenty of RAM and multi-processors, you must download and install it afterward, which thanks to the genius package system of Debian, is very easy to do.
Have a look at Section 8.9 for a more detailed description of apt-get and dpkg.
The keyword to look for when you want a Linux kernel with support for more RAM than LOWMEM=940M and more than one CPU, is SMP, aka Symmetric Multi-Processors. This command issued from a shell, will list available Linux kernels, ready for installation:
apt-cache search kernel-image | grep smp
At the time this is being written, this returns:kernel-image-2.4-686-smp - Linux kernel image for version 2.4 on PPro/Celeron/PII/PIII/P4 SMP kernel-image-2.4-k7-smp - Linux kernel image for version 2.4 on AMD K7 SMP kernel-image-2.4.27-2-686-smp - Linux kernel image for version 2.4.27 on PPro/Celeron/PII/PIII/P4 SMP kernel-image-2.4.27-2-k7-smp - Linux kernel image for version 2.4.27 on AMD K7 SMP kernel-image-2.6-686-smp - Linux kernel image for version 2.6 on PPro/Celeron/PII/PIII/P4 SMP. kernel-image-2.6-amd64-k8-smp - Linux kernel image for version 2.6 on AMD64 SMP systems kernel-image-2.6-em64t-p4-smp - Linux kernel image for version 2.6 on Intel EM64T SMP systems kernel-image-2.6-k7-smp - Linux kernel image for version 2.6 on AMD K7 SMP. kernel-image-2.6.8-11-amd64-k8-smp - Linux kernel image for version 2.6.8 on AMD64 SMP systems kernel-image-2.6.8-11-em64t-p4-smp - Linux kernel image for version 2.6.8 on Intel EM64T SMP systems kernel-image-2.6.8-2-686-smp - Linux kernel image for version 2.6.8 on PPro/Celeron/PII/PIII/P4 SMP. kernel-image-2.6.8-2-k7-smp - Linux kernel image for version 2.6.8 on AMD K7 SMP.
There is no need to explicit specify the kernelversion, like 2.4.27 or 2.6.8, just use 2.4 or 2.6, so the above then boils down to
kernel-image-2.4-686-smp - Linux kernel image for version 2.4 on PPro/Celeron/PII/PIII/P4 SMP kernel-image-2.4-k7-smp - Linux kernel image for version 2.4 on AMD K7 SMP kernel-image-2.6-686-smp - Linux kernel image for version 2.6 on PPro/Celeron/PII/PIII/P4 SMP. kernel-image-2.6-amd64-k8-smp - Linux kernel image for version 2.6 on AMD64 SMP systems kernel-image-2.6-em64t-p4-smp - Linux kernel image for version 2.6 on Intel EM64T SMP systems kernel-image-2.6-k7-smp - Linux kernel image for version 2.6 on AMD K7 SMP.
Now you just need to know what kind of processor you have, 686 (Intel), k7 (AMD), AMD64 or EM64T
Once you know which kernel is the correct one for your machine, you can install it with the command
apt-get install kernel-image-2.6-<your cpu>-smp
If you have Intel Xeon you would use
apt-get install kernel-image-2.6-686-smp
Or if you use 2.4-kernel
apt-get install kernel-image-2.4-<your cpu>-smp
If you have AMD Athlon(TM) MP 2000 you would use
apt-get install kernel-image-2.6-k7-smp
When you install the new kernel, you may see something like this:
tjener:~# apt-get update
tjener:~# apt-get install kernel-image-2.6-686-smp
Reading Package Lists... Done
Building Dependency Tree... Done
The following extra packages will be installed:
kernel-image-2.6.8-2-686-smp
Suggested packages:
lilo kernel-doc-2.6.8 kernel-source-2.6.8
Recommended packages:
irqbalance
The following NEW packages will be installed:
kernel-image-2.6-686-smp kernel-image-2.6.8-2-686-smp
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 15.3MB of archives.
After unpacking 44.9MB of additional disk space will be used.
Do you want to continue? [Y/n]
Get:1 http://ftp.debian.org sarge/main kernel-image-2.6.8-2-686-smp 2.6.8-16 [15.3MB]
Get:2 http://ftp.debian.org sarge/main kernel-image-2.6-686-smp 101 [2154B]
Fetched 15.3MB in 1m13s (208kB/s)
Selecting previously deselected package kernel-image-2.6.8-2-686-smp.
(Reading database ... 80762 files and directories currently installed.)
Unpacking kernel-image-2.6.8-2-686-smp (from .../kernel-image-2.6.8-2-686-smp_2.6.8-16_i386.deb) ...
Selecting previously deselected package kernel-image-2.6-686-smp.
Unpacking kernel-image-2.6-686-smp (from .../kernel-image-2.6-686-smp_101_i386.deb) ...
Setting up kernel-image-2.6.8-2-686-smp (2.6.8-16) ...
File descriptor 3 left open
File descriptor 4 left open
File descriptor 5 left open
File descriptor 6 left open
File descriptor 7 left open
Finding all volume groups
Finding volume group "vg_data"
Finding volume group "vg_system"
Searching for GRUB installation directory ... found: /boot/grub .
Testing for an existing GRUB menu.list file... found: /boot/grub/menu.lst .
Searching for splash image... none found, skipping...
Found kernel: /boot/vmlinuz-2.6.8-2-686-smp
Found kernel: /boot/vmlinuz-2.6.8-2-386
Updating /boot/grub/menu.lst ... done
Setting up kernel-image-2.6-686-smp (101) ...
You see here that I asked for the installation of kernel-image-2.6-686-smp, and it automatically translated that into installing kernel kernel-image-2.6.8-2-686-smp, and it also suggests some other packages to install.
 | You Need to Reboot. |
|---|---|
In order for the newly-installed kernel to be taken into use, you must reboot. This is the only time you ever need to reboot your Skolelinux/Debian-edu machine, while installing other programs. There is no need for a reboot, except when installing a new kernel. |
After you have installed a SMP-enabled kernel, and have rebooted your machine, you can use the commands free and cat /proc/cpuinfo to see if the newly-installed kernel sees all of your processors and RAM;
ltspserver00:~#free
total used free shared buffers cached
Mem: 4074752 4045556 29196 0 339248 2327780
-/+ buffers/cache: 1378528 2696224
Swap: 1835000 5852 1829148
Here I have trimmed the output a bit, removed the unnecessary output.
ltspserver00:~# cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Xeon(TM) CPU 2.66GHz processor : 1 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Xeon(TM) CPU 2.66GHz processor : 2 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Xeon(TM) CPU 2.66GHz processor : 3 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Xeon(TM) CPU 2.66GHz
If you now run uname -a after you have installed a new kernel, you will see
tjener:~# uname -a Linux tjener.intern 2.6.8-2-686-smp #1 SMP Thu May 19 17:27:55 JST 2005 i686 GNU/Linux