IBM 990 - Manual (Page 147)

Chapter 6. Software support 135
z990 compatibility for selected OS/390 and z/OS releases
OS/390 V2.10, z/OS V1.2, and z/OS V1.3 require the Web delivered Compatibility Support to
run on a z990.
Compatibility Support allows these releases to:
Define a z990 environment with HCD
Run on a z990 processor in a logical partition in LCSS-0, using an LPAR ID equal to or
less than x’F’
Coexist in a sysplex that contains a z990 processor
Coexist with z990 processors sharing disk devices outside of a sysplex
Compatibility Support requirements
Compatibility Support is required under the following circumstances:
Compatibility Support is required for all images running on a z990.
Compatibility Support is required on any image that is used for defining the I/O
configuration for the z990.
Compatibility Support is required on all images in a sysplex, whether running on a z990 or
not, if a Coupling Facility logical partition for that sysplex is running on a z990 and has an
LPAR identifier greater than 15 ( x’F’).
Compatibility Support allows the supported operating systems to run in LCSS 0 on the z990
processor. It is not possible to run z/OS or OS/390 in LCSSs 1, 2, and 3, even with the
compatibility maintenance. This is supported on z/OS 1.4 with the Exploitation Support and
subsequent releases.
Compatibility Support can run on any processor that is already supported by one of the listed
operating systems. For example, you can install Compatibility Support on a z/OS V1.2 system
that is running on an IBM 9672 G5 processor.
Figure 6-1 on page 136 shows a situation where the Compatibility Support is not required for
systems not on the z990.
Attention: Compatibility and Exploitation Support is not available for z/OS 1.1
Note: A Coupling Facility logical partition can reside in any Logical Channel Subsystem.