Linux on pSeries Overview
In examining a port to Linux on pSeries, there is a benefit for ISVs that may be overlooked. iSeries and pSeries both use the POWER chip set. For many applications, a port to the POWER architecture can yield an application on both platforms. In the Linux Standard Base (LSB), there is one specification and toolset for POWER64 that applies to both platforms. In many commercial applications, both platforms can use the same application binary. This can give an ISV two new application platforms for one porting investment.
Porting
The port is most often accomplished by just recompiling code that runs on another hardware platform, especially if it is already LSB compliant. White papers that describe aspects of porting to POWER are the following:
In addition to possible use a single binary, there are many other common advantages in the iSeries and pSeries support for Linux. The same technology concepts can be applied on both series. Both series provide the environment in which to run a Linux distribution. Both iSeries and pSeries can run Linux in a logical partition, side by side with partitions with other operating environments. Both can readily share data between Linux and other operating environments on the same system footprint. Both can provide enhanced management support for Linux by integrating with other OS capabilities. Commonality of Linux support and use on iSeries and pSeries is highlighted in an overview presentation and an IBM white paper on POWER commonality.
Additional series-specific information can be found in the Linux on pSeries Overview
The commercial Linux distributions that support the broadest set of these POWER server models have a 64-bit kernel with either 32-bit application support or 32- and 64-bit application support above the 64-bit kernel. You should use the 64-bit kernel on POWER systems for increased potential scalability. Because both 32- and 64-bit addressing are present in the chip set, there is no emulation or performance penalty for running a 32-bit application on the 64-bit kernel. The formal distribution support for the POWER series can be seen on the distribution support table.
Work is currently underway to complete the POWER64 LSB specification and tools so that LSB conformance can be achieved on POWER architecture systems.
General Porting Guides and Migration toolkit
Middleware
If you use open source or third party middleware in your solution, you will want to ensure that is has been ported to the POWER architecture also. IBM Software Group has been releasing some of its key middleware offerings for the POWER architecture over the past few months.
Additional tools and compilers are also available.
Infrastructure
For system and software access, pSeries is well represented in the IBM Linux Test Drive program.
To boost your Linux on POWER technology skills, IBM also offers an
introduction to Linux for POWER workshop
in addition to general Linux development education.
The currently available toolsets for POWER technology are part of the distributions that are available on pSeries.
Speed-start your Linux app 2004 web site is a good place to start when considering migrating your application
to Linux on pSeries.
Because customer expectations for iSeries and pSeries are high, especially in the support area, you will want to be familiar with the IBM support processes. When you are adding a Linux application to the eServer platform from IBM and a Linux distribution from a distributor, you will want to plan for an effective 3-way conversation on support questions. While this is "business as usual" in the Linux community, some famliarity in advance can ensure that the paths are smooth for your eServer customers.
Tailoring
The first point to remember is "Linux is Linux." It is usually not necessary to tailor the application
to conclude a successful port. Linux runs natively (directly on the processor) on all the pSeries Linux-capable systems. Many IBM eServer technologies provide "extras" that can be exploited without changing your core application to help you deliver a higher-value solution on the pSeries systems.
- Hardware partitioning: IBM pSeries Linux-capable servers provide the capability to run Linux, AIX or both on a single server.
- Performance: IBM pSeries Linux servers provide large memory capabilities, advanced floating point computing, 64-bit addressability and tuned compilers. These features allow companies to take full advantage
of POWER4 technology to deliver high-performance applications, backed by a proven architecture. If your application is performance sensitive, you might want to look a look at this POWER4 Tuning Guide.
|
] 
