Linux on iSeries Overview
In examining a port to Linux on iSeries, 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 target 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 at
Linux on iSeries Overview site.
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.
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.
These and other useful tools can be downloaded for trials from our
Linux on POWER
speed start program.
Infrastructure
For system and software access, iSeries is well represented in the IBM Linux hardware access and support programs.
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 iSeries.
Speed-start your Linux app 2003 web site is a good place to start when considering migrating your application
to Linux on iSeries.
Because customer expectations for iSeries 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
While "Linux is Linux" to the extent that iSeries customers generally get their Linux from one of the Linux distributors, there are aspects of the iSeries environment that can be used by Linux application providers to deliver an enhanced Linux solution on iSeries. Some of the aspects are:
Hardware partitioning that allows you to give a part of a processor to a Linux partition and to move the processor allocation from partition to partition when different workloads need it.
Data management and file backup that makes it easy to integrate the backup of Linux data with the backup of other system data on a predefined schedule. Linux applications also can readily access pre-existing DB2 data from OS/400.
Integration with other OS environments, in the case of iSeries, OS/400 and its AIX runtime.
Other iSeries tailoring aspects can be found on the OS/400 tailoring page
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