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
devicesemulated printers and card readers are good examplesfor 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.
5
The same situation exists with a P/390 or MP3000 emulated I/O LAN adapter. It is known as the MPTS number in
these cases.

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