EFS Systems on a Linux Base: Getting Started

Chapter 1. Introduction 3

1.2 Terminology

EFS descriptions can become confusing if the terminology is not well defined. These are

important terms:

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Processor means a PC processor. ThinkPads have a single processor, while some PC

servers have multiple processors.

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Processor(s) enabled for S/390 refers to the number of PC processors that the FLEX-ES

license allows to be used simultaneously for S/390 emulation.

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Server means the underlying PC hardware.

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Server operating system means Linux in the PC.

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S/390 CPU (or simply CPU) means an emulated single S/390 CPU engine.

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S/390 system means an emulated S/390 (in the EFS system) that might have more than

one emulated S/390 CPU engine.

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Instance (or FLEX-ES instance) means an emulated S/390 system. We can run several

FLEX-ES instances if we have sufficient PC resources.

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z/OS means the S/390 operating system. We could also use OS/390, z/VM, VM/ESA,

Linux for S/390, or VSE/ESA, but we elected to work only with z/OS.

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ThinkPad EFS and xSeries® EFS are generic names. Business Partners providing these

products often have their own names for their specific implementation of the products.

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IBM ~ xSeries is the name of an IBM product line. Older products used the name

Netfinity®.

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S/390, in this document only, is used to include both S/390 and zSeries functionality. This

abbreviated reference is solely for readability.

For any

FLEX-ES instance, there is usually a one-to-one correspondence between

processors enabled for S/390 and S/390 CPUs. Running multiple instances is something like

running multiple z/OSs in separate logical partitions (LPARs), but it is not quite the same. We

can run multiple

instances of single-CPU S/390s in a ThinkPad EFS system, for example.

1.3 Connectivity overview

An EFS system can be self-contained in a PC. That is, the system can provide the required

S/390 emulation plus several 3270 terminal sessions for a z/OS operator console and VTAM®

(TSO, CICS®, and so forth) terminals. It can also provide ASCII Telnet sessions for direct

logon to z/OS UNIX System Services. The number of terminal sessions (3270 and ASCII

Telnet) is limited by the screen space available for reasonable use on the PC display. For

practical purposes, this is a single-user system.

We can easily make a multi-user system by connecting the system to a LAN. This typically is

done with a single Ethernet interface. The single LAN connection, as illustrated in Figure 1-2

on page 4, can be used in a number of ways at the same time:

򐂰 Client workstations, using 3270 emulators, can connect to a TN3270e

server running

under Linux in the EFS system. This server is the FLEX-ES Terminal Solicitor. It

transforms client TN3270e connections to appear as local, channel-attached, non-SNA

DFT 3270 terminals that can be used as z/OS operator consoles or VTAM (TSO, CICS)

Note: Throughout this book, we frequently refer to the IBM Redbook S/390 PartnerWorld

for Developers, ITSO/EFS Project EFS Systems on a Linux Base: Additional Topics,

SG24-7008.