Multiprocessing & Kernel Configuration

About two months ago, I received a DayStar Digital Genesis MP 600 with a quad 604 200 MHz CPU module and a quad 604 132 CPU module as a gift from some friends of mine. If you have never seen one in person, this is big, heavy, and loud. Its metal case could stop a bullet. Originally selling for $12,000, it was definitely made to take a beating.

For the first few days, I wasn't quite sure what to do with it, but like all systems I have laying around my apartment, I decided to make a server out of it. In my head it would make a nice all purpose server, and I could compress what I have spread across multiple servers into this one system.

The first thing I needed to decide on was what operating system to run. I could use the Mac OS, but it doesn't make a very good server - especially when it comes to using four processors. If I were using Photoshop, that would be one thing, but I am not a graphics guy.

BeOS crossed my mind for a minute, because of it's excellent scaling on four processors, but the problem with BeOS is that it is not a server OS. It can't do NFS, DNS, email, file sharing, and so on.

I finally settled on LinuxPPC, which I didn't want to use at first because I had never had built my own kernel before. The reason for having to build your own kernel is that stock kernels that ship with the LinuxPPC distribution (and others) are compiled for only one processor.

You can go two routes when getting a new kernel: download a precompiled kernel or download the source code and compile it on your own. I prefer to build my own, because I have more control over what is and what is not going to be supported on my system.

Either way you decide to go, the place to get it is at kernel.org. One thing I did need to learn about was kernel version numbers and what they mean. Even numbered kernels are official, and odd numbered ones are development kernels. So 2.2 and 2.4 are official, with 2.1 and 2.3 being development.

The latest kernel right now is 2.4.0, which at this time does not compile properly on Macs and results in some sort of MMU error while compiling. There are some precompiled 2.4 kernels over at Linuxppc.org, but I cannot testify as to how stable they are.

In the meantime, the latest kernel (that works) for Macintosh's is 2.2.18, which compiles just fine. Ftp to kernel.org, grab the 2.2.18 kernel source (ftp://ftp.kernel.org/pub/linux/kernel/v2.2/linux-2.2.18.tar.gz), and while in Linux perform the following commands.

gzip -d linux-2.2.18.tar.gz
tar -xf linux-2.2.18.tar
mv linux /usr/src/linux-2.2.18
rm linux
ln -s linux-2.2.18 linux

In a nutshell, what you have just done is decompress the source code and move it to the /usr/src directory, which is where it needs to be. You have also created a symbolic link from the linux-2.2.18 directory to point to /usr/src/linux, which is good to do, because if you get in the habit now you won't shoot yourself in the foot later if you ever deal with Linux systems on other platforms.

Once all that is done, go into the /usr/src/linux directory and type "make menuconfig." (You did remember to select your development packages during the Linux install right?) You will be presented with a menu of options ranging from "Platform Support" to "Block Devices." From there just select what you want and what you don't want your kernel to support with the space bar. In my case, I want "Multiprocessing Support" under the Platform support section. I will also be removing IDE support, because my DayStar doesn't use IDE and I have no intentions on adding IDE to it right now.

You may notice that certain options are marked with an M, which stands for module. Think of modules as Mac OS system extensions that can be turned off and on without rebooting. If something is marked with an M and you think you want it to always be on, just hit space bar until it has an asterisk like everything else you selected.