Understand the endianess and the benefits of Red Hat Enterprise Linux, little endian, and what is the Red Hat strategy for Power Systems, including the Red Hat Enterprise Virtualization for Power.

1. 9.0
Filipe Miranda <fmiranda@redhat.com>
Global Lead for Red Hat Products on IBM z Systems and Power Systems
Red Hat Inc.
Understanding the Endianess and the
benefits Red Hat Enterprise Linux for
Power, little endian
© Copyright Red Hat Inc 2014

2. Topics for this session
Red Hat in a nutshell
Overview of the collaboration between Red Hat and IBM
Understanding the Endianess
Linux on IBM Power Systems
- Advantages of Running Linux on Power Systems
- Advantages of Little Endian
RHEV for Power
- Welcome to the Red Hat EnterpriseVirtualization
- Advantages of RHEV for Power
- Red Hat strategy for Power Systems
© Copyright Red Hat Inc 2014

3. © Copyright Red Hat Inc 2014
Red Hat in a Nutshell
* Red Hat Client Data, 2014

4. More than 13 years of collaboration between Red Hat and IBM to offer choice to our
customers:
Red Hat Enterprise Linux Certified on all IBM platforms
Red Hat and IBM Collaboration
z Systems
© Copyright Red Hat Inc 2014

5. 9.0© Copyright Red Hat Inc 2014
Understanding Endianess

6. Red Hat Enterprise Linux 7.1 Beta
© Copyright Red Hat Inc 2014© Copyright Red Hat Inc 2014
"Customers who are using the IBM Power Systems platform as part of their
datacenter infrastructure, Red Hat Enterprise Linux 7.1 beta now includes support for
POWER8 on IBM Power Systems (based on little endian)."
https://www.redhat.com/en/about/blog/red-hat-enterprise-linux-71-beta-now-available

7. Endianess
© Copyright Red Hat Inc 2014
The terms endian and endianness refer to the convention used to interpret the data when are
stored in computer memory.
In computing, memory commonly stores binary data by organizing it into 8-bit units called bytes.
When reading or writing data, into memory, consisting of multiple bits, the order of the bytes
stored in memory determines the interpretation of the data.
What is endian and endianness?

8. © Copyright Red Hat Inc 2014
Each byte of data in memory has its own address.
Big-endian systems store the most significant byte in the smallest address and the least
significant byte is stored in the largest address
Endianess
Little-endian systems, in contrast, store the least significant byte in the smallest address.

9. © Copyright Red Hat Inc 2014
Both forms of endianness are in widespread use in computing and networking.
As examples, the Intel x86 processor represents a common little-endian architecture, IBM z
Systems and IBM Power Systems all big-endian; starting with IBM POWER8, IBM Power
Systems now offers a hybrid architecture, both little-endian and big-endian.
Endianness is important as a low-level attribute of a particular data format.
Failure to account for varying endianness across architectures when writing software code
for mixed platforms and when exchanging certain types of data might lead to failures and
data corruption.
Endianess
Why is the endianness important ?

10. 9.0© Copyright Red Hat Inc 2014
Linux on Power Systems

11. Linux on Power Systems
© Copyright Red Hat Inc 2014
Most applications from x86 will work on Red Hat Enterprise Linux LE, and require a simple
recompile.
Red Hat has made it easier for customers to have choice and flexibility, however simply
migrating Linux applications from an x86 machine to a IBM Power Systems server doesn't
guarantee it will work.
Here are several architecture-specific differences you should consider before porting your
x86 Linux applications to Power-based platforms:
• Endianness or byte ordering
• Data type length in 32- and 64-bit environments
• Data alignment differences in the architectures

12. Linux on Power Systems
© Copyright Red Hat Inc 2014
Why Run Linux on IBM Power Platform?
Raw performance: You may be running a large Linux server farm but not getting satisfactory
performance.You may need massive horsepower, and your application might not work well with a
clustering of PCs.
Virtualization: You may want the maximum flexibility you can have to share unused resources,
allocate and logically partition your servers.
Leveraging existing resources: You may already have a large staff of Linux support personnel.
You've fallen in love with the Power Systems platform for all of the reasons mentioned so far and
don't want to invest the money in retraining your staff on UNIX.
Datacenter consolidation: Sometimes, it seems every large company over the past several years
has performed a server consolidation of some kind.
Etc…

13. Linux on Power Systems
© Copyright Red Hat Inc 2014
The bottom line is, by combining the flexibility and cost savings
of Linux with the scalability and robustness of the POWER
platform, customers across all industries can integrate their
environments using Linux on POWER to reduce costs and
consolidate workloads.

14. © Copyright Red Hat Inc 2014
Red Hat’s latest version (RHEL 7.1) includes support for IBM Power Systems running in little
endian architecture mode.
Running little endian mode accelerates business application innovation by eliminating a significant
and outdated barrier to application portability and allowing customers with the latest IBM Power
Systems to leverage the significant existing ecosystem of Linux applications previously developed
and restricted to x86 architectures.
This is significant because it increases business’ choice, flexibility and access to open standard
solutions. It eases application migration from one platform to the other to take advantage of
innovation anywhere, and any time. It enables simple data migration, simplifies data sharing
(interoperability) with Linux on x86, and improves I/O options with modern I/O adapters and
devices, e.g. GPUs.
Red Hat Enterprise Linux for Power, Little Endian
Why run Linux Little endian on Power Systems ?

15. Why Little endian now?
© Copyright Red Hat Inc 2014
The issue of big endian/little endian operating mode initially allowed applications developers to
maximize application performance by exploiting differences in processor architectures.
The difference also worked to the advantage of proprietary-minded vendors by reducing
application portability as it tied applications more tightly to specific platform architectures.
Important in the last century, all this changed under the pressures of open computing.

16. 9.0© Copyright Red Hat Inc 2014
Virtualization Strategy

17. RHEV for Power
© Copyright Red Hat Inc 2014
Virtualization Strategy
IBM PowerVM

18. © Copyright Red Hat Inc 2014
RHEV for Power
• Coexist with RHEV environments for x86: Simply add Power Systems with Linux guests
to the current x86 environment and take advantage of a single graphical console to
manage both distributed systems and Power Systems.
• Open SourceTechnology: Using RHEV for Power will allow customers to benefit from
the KVM virtualization technology without having to learn another hypervisor (IBM
PowerVM) when managing Linux guests.
• Readily available staff with KVM knowledge versus PowerVM
• By using RHEV for Power, or simply RHEV - you can integrate your environment with
other products from Red Hat, such as Cloudforms, to manage Linux cloud environments.
What are the advantages of RHEV for Power?

19. RHEV Manager
© Copyright Red Hat Inc 2014

20. Roadmap Summary*
Phase I:
• Red Hat EnterpriseVirtualization for Power, big endian
• Red Hat Enterprise Linux for Power, big endian
• Red Hat Enterprise Linux for Power big endian with SmartVirtualization
© Copyright Red Hat Inc 2014
Phase II:
• Red Hat Enterprise Linux for Power, little endian
Phase III:
• Red Hat EnterpriseVirtualization for Power, little endian
• Red Hat Enterprise Linux for Power, little endian
• Red Hat Enterprise Linux for Power little endian with SmartVirtualization
* Subject to change without further warning

21. Filipe Miranda <fmiranda@redhat.com>
Global Lead for Red Hat Products on IBM z Systems and Power Systems
Red Hat Inc.
Sources:
http://en.wikipedia.org/wiki/Endianness
http://www.ibmsystemsmag.com/aix/trends/linux/Linux-on-POWER/?page=1
http://www.zdnet.com/article/red-hat-joins-the-ibm-power8-party/
http://openpowerfoundation.org/introducing-the-little-endian-openpower-
software-development-environment-and-its-application-programming-interfaces/
http://ptakassociates.blogspot.com/2014/12/red-hats-release-of-linux-71-little.html