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If your Linux distribution supports the "VM shared kernel support" configuration option, the Linux kernel can be generated as a shareable NSS (named saved system). Once generated with this option, the system must be IPLed, stopped at location x'10000' and saved (from a class E user) with something like the following example from a 64M machine:

DEFSYS LXSHR 0-FF EW 100-2FF SR 300-4FF EW MINSIZE=64M
SAVESYS LXSHR

Once this is done, any VM user can IPL LXSHR and about 1.5M of the kernel is shared among all users. Obviously, the more Linux virtual machines running, the greater the benefit of using the shared system.

Note:
Every virtual machine that IPLs your shared system must have the same disk configuration as the system that was saved. That is, the disks must be at the same addresses and be the same sizes as the virtual machine that issued the SAVESYS command.

An example of how to use VM Shared Kernel Support

Below is a sample EXEC that can be used to help you create a shared Linux NSS. Once you have generated a kernel with the "VM shared kernel support" config option and have that kernel ready to IPL from a device, the EXEC can be used as follows:

Userid Class
The VM userid that will run the EXEC should be a class E VM userid.

Storage size
The userid virtual machine storage should be defined to whatever size you want as the minimum size of the virtual machine to IPL your shared system. At least 64M is recommended.

Invoking the SAVELX EXEC

   SAVELX system_name device_number

system_name

is the name you want to give to your shared system (e.g. lxshr)

device_number

is the device number that you usually IPL to start your Linux system.

I system_name

Sample SAVELX EXEC

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This information contains sample application programs in source language, which illustrates programming techniques on various operating platforms. You may copy, modify, and distribute these sample programs in any form without payment to IBM, for the purpose of developing, using, marketing or distributing application programs conforming to the application programming interface for the operating platforms for which the sample programs are written. These examples have not been thoroughly tested under all conditions. IBM, therefore, cannot guarantee or imply reliability, serviceability, or function of these programs.

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