IBM s/390 manual Cloned devices, 80 S/390 PID ThinkPad Enabled for S/390

The cu type 3172 is a defined FLEX-ES keyword and defines an LCS-type LAN connection to S/390. (On the S/390 side, there would normally be two CTC addresses (even/odd addresses) defined. A LAN device for use by OS/390 TCP/IP must be specified exactly as shown (except that the device name of the interface might be different). That is, it will be defined as two devices (00 and 01), with the second device OFFLINE. The IP address for this interface would be specified in the OS/390 TCP/IP profile.

The device designation in this example, eth0, may appear strange to experienced UNIX users, who will want to write something like /dev/eth0. However, eth0 worked on our ThinkPad/EFS; furthermore, Linux does not appear to define names like /dev/eth0 or /dev/net0.

An additional parameter may be required for a LAN definition. A “real” 3172 unit may have up to four adapters. These are numbered 0-3, and this number appears in the OS/390 TCP/IP or VTAM specifications.5 By default, FLEX-ES uses number zero. If you want a different number, you must include an options statement:

R10A3088: cu 3172

options ‘adapternumber=1’ interface local(1) device(00) 3172 eth0 device(01) 3172 OFFLINE

end R10A3088

This emulates the “real” 3172 adapter number 1. This is not related to the actual LAN adapter number in your ThinkPad. The actual Netfinity LAN adapter that is used is specified by the device parameter.

You can share a LAN adapter between Linux and OS/390 TCP/IPs. In order to do this, you need to specify the IP address to be used by OS/390, as a parameter in the resource definition. (You should specify the same address in your OS/390 TCP/IP parameters.) For example,

R10A3088: cu 3172

options ‘ipaddress=9.12.17.211’ interface local(1) device(00) 3172 eth0 device(01) 3172 OFFLINE

end R10A3088

Using this example, the single Ethernet adapter in our ThinkPad/EFS machine appears as IP address 9.12.17.210 (defined when we installed Linux) and 9.12.17.211 (when we start FLEX-ES).

Cloned devices

The FLEX-ES documentation includes an optional cloned parameter for many resources definitions. We did not use this parameter. This parameter applies to a limited set of devices—emulated printers and card readers are good examples—for which the resources definitions can be automatically replicated to serve multiple S/390 instances. This is meaningful only when multiple S/390 instances are used. It potentially saves a little time when creating resources definitions. We suggest it may be better to take the extra time to directly create all the resources definitions you need and ignore the cloned parameter.

5The same situation exists with a P/390 or MP3000 emulated I/O LAN adapter. It is known as the MPTS number in these cases.

80S/390 PID: ThinkPad Enabled for S/390