Migration to z/OS
IBM is providing the z/OS Bimodal Accommodation offering in response to
your requests for an alternative to running in 64-bit mode when first
migrating to z/OS 1.2, 1.3, or 1.4 on a z/Architecture server
or equivalent). Previously, z/OS had to run in 64-bit z/Architecture mode
on a z/Architecture server. This offering gives you the security of
knowing you can return to 31-bit mode if there are any 64-bit issues
during your migration.
The bimodal accommodation offering will not be provided for z/OS 1.5.
Download this offering from the Web!
This offering is only available for a 6-month period on each z/Architecture
server. The 6 months begins when z/OS is licensed to the server. This
offering will be available at no charge.
You can download the Accommodation offering from the
z/OS downloads Web page now.
Recommended migration paths
You can now migrate from OS/390 to z/OS on your 31-bit server
with the confidence that you can make a smooth transition to
z/Architecture when you install z/Architecture servers in the future.
When you install a zSeries server, your migration to
z/Architecture is made simpler and more fail-safe with the Accommodation
The 6-month window begins when you license z/OS on a z/Architecture server.
64-bit mode on zSeries - Ready for business
IBM still recommends that you migrate directly to 64-bit z/Architecture mode
when you install a z/800, z/900, or z990 if you are already running z/OS on a
G5, G6, or Multiprise 3000 server. Significant testing has been completed since the
introduction of 64-bit mode support with OS/390 2.10 in September 2000.
z/OS 1.4 is the fourth z/Architecture release and many customers are running
production systems in 64-bit mode. These environments include a long list
of ISV products.
As with any migration, you should check all of your ISV products to
validate their support on the new z/OS release. ISV products can require
maintenance or a new release to run on the new z/OS release. It is expected
that there should be
very few situations where you'll need to fall back to 31-bit mode, but we're
glad to provide this "safety net" to you to assist in your migration plans to
move forward to z/OS.
z/OS in 31-bit mode - Functional limitation
The Bimodal Accommodation Migration offering does not extend support to those
functions previously announced as requiring z/Architecture (64-bit).
This includes, but is not limited to: Intelligent Resource Director,
HiperSockets, 64-bit Real Storage, 64-bit Virtual Storage, and IPv6.
In addition, Workload License Charges on z900 servers will not be available.
z/OS.e is not supported by the Bimodal Migration Accommodation offering.
Send us your questions and comments.