S390/Hercules

Overview
Installing Gentoo on a hercules...etc

Requirements
To be able to install Gentoo, you'll need the following:


 * A machine that is able to run Hercules
 * Hercules, the emulator
 * A network connection
 * iptables if you want to add networking to hercules

Overview
For installing Gentoo, we're going to transfer the installation files...

Choosing the userland
Before going further with the process, we have to choose which userland we want to install.

In Gentoo we provide two userlands: a 31-bit one, which in the Linux on zSeries is named as s390 and a 64-bit one, which in the Linux on zSeries is called s390x.

Downloading the installation images
Once you've made up your choice, you can now download the needed files from the mirrors in the experimental directory, blablabla...

Adjusting boot parameters for the installation image
One of the files you've downloadesomething.params'gentoo.params''. You need to edit this file and adjust the dasd=xxx parameter according to your z/VM environment.

If your DASD has the 0190 ID, then you need to put dasd=0190. If you have more than one DASD you can append the IDs of them to the dasd parameter, like dasd=0190,0191,0192, etc.

That will translate, in the Linux environment, the 0190 DASD as /dev/dasda, 0191 as /dev/dasdb and so on...

Create the work directory
Let's create a directory where our VM will be located, so we can put in there all the files we need. For example, /home/user/hercules.

Create the following directories: dasd, rdr and prt

Download the files from http:// to the rdr directory.

Create a configuration file for hercules, let's call it s390x.cnf with this content:

From the first part, the important parameters are CPUMODEL, which specifies which kind of machine we are emulating. Note that Hercules doesn't support all the machines. MAINSIZE the RAM quantity you want to use for the VM. NUMCPU is the number of cores you want the VM to have. There are some reports in Debian that Hercules doesn't work well with a high quantity of cores.