Specifications

76 IBM System z Personal Development Tool: Volume 3 Additional Topics
6.1 Multiple instances or guests
We strongly suggest that you use a single zPDT instance, as described in this series of
documents, to become familiar with basic zPDT operation. Also, you cannot exceed the
number of zPDT licenses in your token(s). The same number of token licenses applies
whether the zPDT CPs are in a single instance or spread over multiple instances.
Multiple instances means running more than one copy of zPDT. Each instance must run
under a different Linux userid. This can be accomplished by logins through telnet (or ssh) or
by careful use of su commands from different windows on the Linux desktop. The .bashrc file
of each userid must have the appropriate export statements. Each instance must have its own
devmap.
The use of TCP/IP interfaces is an essential part of this discussion. For this reason we
combine a discussion of multiple zPDT instances with the use of guests under z/VM in a
single instance. Our examples use OSD (QDIO) interfaces for TCP/IP. It is possible to use
OSE interfaces (non-QDIO) for TCP/IP; however, in the case of multiple instances using OSE
(through a single emulated OSA) you must configure the OSA Address Table (OAT) using the
OSA/SF utility.
6.2 Multiple guests in one instance
A typical z/VM configuration is outlined in Figure 6-1. z/VM itself typically “owns” all the 3270
sessions. Guests (z/OS, CMS) acquire a 3270 when a user logs on to the guest or uses a
dial command.
Figure 6-1 Guests in a single zPDT instance
Each guest (under z/VM) can access a LAN interface. The awsosa device manager can
handle up to 16 of these “stacks”. An awsosa device manager using a tunnel to Linux can be
used, as shown in the illustration. Each z/VM guest would use different IP addresses on each
OSA interface. Alternatively, not shown in the illustration, z/VM could establish an internal
Linux
awsosa
zPDT Instance
CP z/VM
z/OS guest
TCP/IP
awsosa
z/OS guest
TCP/IP
Local x3270 sessions
Linux TCP/IP
aws3274
Tunnel
aws3274 emulates multiple local 3270s. z/VM
typically "owns" the 3270s and allows guests to
use them via the "dial" function or via logon.
awsosa supports multiple TCP/IP stacks.
It can connect to z/VM and the guests.
Ethernet adapter
This instance has one CP.