IBM z/OS z/OS Planning for Installation, Migration, installation and customization enhancements

This consistent coexistence, migration and fallback policy

applies to release migrations for:

• Single system conﬁ gurations• Individual systems within a multisystem conﬁ guration• Cases where a simultaneous IPL is used to migrate all systems in a multisystem conﬁ guration at the same time.

For additional information on coexistence and release

migration information, refer to

z/OS Planning for Installation

(GA22-7504) at: ibm.com/servers/eserver/zseries/zos/

bkserv/ﬁ nd_books.html.

The following table describes the migration/coexistence

supported releases. The release shown in column 1 is the

highest release running in a multisystem conﬁ guration.

Migration/Coexistence Supported Releases (OS/390 & z/OS)

Release Migration/Coexistence Release

z/OS R4 z/OS R4, z/OS R3, z/OS R2, {z/OS R1, OS/390 R10}

z/OS R5 z/OS R5, z/OS R4, z/OS R3, z/OS R2

z/OS R6 z/OS R6, z/OS R5, z/OS R4, z/OS R3

z/OS R72 z/OS R7, z/OS R6, z/OS R5, z/OS R4

1. OS/390 R10 and z/OS R1 treated as one coexistence level

2. z/OS R7 is planned to be available September 2005

This information is being provided to you to facilitate

release planning and to help ensure appropriate position-

ing for future software migrations.

Note: Speciﬁ c functions might only be available on the

up-level systems, or it might be necessary to up-level all

systems to enable some functions.

For additional information on z/OS planning, refer to z/OS

and z/OS.e Planning for Installation, available on the z/OS

Web site in the z/OS Library at: ibm.com/servers/eserver/

zseries/zos.

For the latest information regarding z/OS and OS/390

marketing and service withdrawal dates visit: ibm.com/

servers/eserver/zseries/zos/support/zos_eos_dates.html.

Migration, installation and customization enhancements

For information on migration to the latest z/OS releases,

see the z/OS Migration Web page ibm.com/zseries/zos/

migration. The publications are available from this site for

helping to plan the migration to z/OS 1.6.

zSeries Bimodal Support for z/OS

IBM provides is announcing the z/OS Bimodal Migration

Accommodation Offering to assist customers in migrat-

ing from OS/390 to z/OS. This addresses many customer

requests to have a “fallback” option to 31-bit mode when

ﬁ rst migrating to z/OS in 64-bit mode on a z/Architecture

server. IBM has reconsidered the investment in 31-bit sup-

port on a zSeries server to encourage our customers to

move forward. This offering is available for 6 months for

each z/OS license (5694-A01) starting from the registration

of a z/OS license to a z/Architecture server. This offering

applies to z/OS Version 1 Release 2, 3, and 4, and will not

be provided for z/OS 1.5 or for any z/OS.e releases.