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IBM PASE for i


The IBM i Information Center can introduce you to the IBM Portable Application Solutions Environment (PASE for i)

PASE for i quick facts:

IBM System i and System p share common POWER processors. This hardware has the ability to use different addressing modes: addressing 64-bit tags-active for traditional 64 bit IBM i applications; 64-bit or 32-bit tags-inactive for traditional AIX applications. PASE for i exploits this capability to execute AIX applications within IBM i jobs. Since PASE for i applications execute directly on the hardware, applications use the processor without additional layers or overhead. Computationally intensive applications will experience equivalent performance on AIX or IBM i using PASE for i.

PASE for i is not an operating system. PASE for i is a programming model for IBM i applications. Applications and runtime libraries use the IBM i SLIC kernel for system services. A PASE for i application is therefore naturally integrated with IBM i work management, security, backup, file systems, etc.

PASE for i is a no-charge option of IBM i. PASE for i provides a very large subset of 32-bit and 64-bit AIX syscalls and APIs plus nearly 200 common utilities along with the Korn, Bourne, and C shells.

DB2 for IBM i is the database built into IBM i. The same Call Level Interface (CLI) APIs provided by DB2 for IBM i in ILE are supported for PASE for i. Data returned from DB2 for IBM i is presented in ASCII format, as expected by the majority of UNIX applications. Embedded SQL is not currently available for PASE for i applications.

PASE for i applications can be fully integrated with other IBM i applications, for example an ERP application built in ILE or a WebSphere application written in Java. A mix of application models (ILE, Java, PASE for i) can run together in a single job.

Advantages of porting to IBM i using PASE for i

Customers running applications ported using PASE for i do not need to learn UNIX system administration. PASE for i applications run in IBM i jobs using standard IBM i work management (subsystems, etc), the integrated file system with standard save/restore operations, and standard security. No special system operations are introduced by PASE for i, only new applications.

Leveraging existing UNIX skills of solution providers;
leveraging existing IBM i skills of IBM System i customers

Solution developers porting to IBM i using PASE for i and supporting their applications will require a combination of AIX and IBM i programming and support skills. PASE for i applications may be built and compiled on AIX or built and compiled on IBM i with AIX compilers. Application developers continue to use their existing UNIX skills. IBM i skills are also required for converting database calls, providing integration with IBM i security, and application operational interfaces (installation, start-up, shut-down, etc.).

Solution developers also require some IBM i skills in their support teams as customers will reference IBM i terminology instead of UNIX terminology.

Reducing time to market

Bringing an application to the IBM i market requires three phases of effort: market development, solution enablement (including porting the application) and market introduction. Market development and introduction are efforts common to all techniques of moving applications to IBM i. PASE for i can improve several aspects of the solutions enablement phase. A faster port can mean a shorter time to market.

This is because pointer size assumptions do not change from AIX to PASE for i. ILE applications use either 64-bit or 128-bit pointers. Also, PASE for i runtimes include more flexibility in C language support compared to the full ANSI compliant support provided in ILE C. Some time savings may be achieved in the porting phase by not having to modify the application's build environment. The testing cycle for a PASE for i application may also be more familiar, with the same tools as on AIX.

Packaging and management

There is a second part to enablement after the application is running. All applications, whether ported in ILE or PASE for i require a similar amount of customization to create a product that meets IBM i customers' expectations of full integration with database, save/restore, security, ease of installation, licensing and robust support services. A product integration and test cycle is required for PASE for i applications to fully exploit the environment on IBM i.


For the latest information about PASE for i performance see the IBM i Performance Capabilities Reference. (The PASE information is in Chapter 21.)

Go to the Performance Management on IBM i site, and follow the "Resource Library" link for the latest version of the manual.

Additional Information

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