What is i5/OS PASE?

i5/OS™ PASE is an integrated runtime environment for AIX^® applications running on i5/OS.

It supports the application binary interface (ABI) of AIX, and provides a broad subset of the support provided by AIX shared libraries, shells, and utilities. i5/OS PASE supports the direct processing of IBM^® PowerPC^® machine instructions, so it does not have the drawbacks of an environment that only emulates the machine instructions.

i5/OS PASE applications:

Can be written in C, C++, Fortran, or PowerPC assembler
Use the same binary executable format as AIX PowerPC applications
Run in an i5/OS job
Use i5/OS system functions, such as file systems, security, and sockets

Keep in mind that i5/OS PASE is not a UNIX^® operating system on i5/OS. i5/OS PASE is designed to run AIX programs on i5/OS with little or no change. Programs from any other environment, such as AIX or Linux^®, need to be written such that they can be compiled on AIX as the first step toward running in i5/OS PASE.

The i5/OS PASE integrated run time runs on the Licensed Internal Code kernel on the iSeries™ server. The system provides integration of many common i5/OS functions across i5/OS PASE and other runtime environments (including ILE and Java™). i5/OS PASE implements a broad subset of AIX system calls. System support for i5/OS PASE enforces system security and integrity by controlling what memory an i5/OS PASE program can access and restricting it to use only unprivileged machine instructions.

Rapid application deployment with minimal effort

In many cases, your AIX programs can run in i5/OS PASE with little or no change. The level of AIX programming skills you need varies depending on the design of your AIX program. In addition, by providing additional i5/OS application integration in your program design (for instance, with CL commands), you can minimize configuration concerns for your application users.

i5/OS PASE adds another porting option for solution developers who want to share in the success of the i5/OS marketplace. By providing a means to cut porting time significantly, i5/OS PASE can improve the time to market and return on investment for solutions developers.

A broad subset of AIX technology on i5/OS

i5/OS PASE implements an application run time that is based on a broad subset of AIX technology, including:

Standard C and C++ run time (both threadsafe and non-threadsafe)
Fortran run time (both threadsafe and non-threadsafe)
pthreads threading package
iconv services for data conversion
Berkeley Software Distributions (BSD) equivalent support
X Window System client support with Motif widget set
Pseudo terminal (PTY) support

Applications are developed and compiled on an AIX workstation running a level of AIX that is compatible with a level supported by i5/OS PASE, and then run on i5/OS.

Alternatively, you can install one of the supported compiler products in the i5/OS PASE environment to develop, compile, build, and run your applications completely within i5/OS PASE.

i5/OS PASE also includes the Korn, Bourne, and C shells and nearly 200 utilities that provide a powerful scripting environment.

i5/OS PASE uses IBM investment in a common processor technology for the AIX and i5/OS operating systems. The PowerPC processor switches from i5/OS mode into AIX mode to run an application in the i5/OS PASE run time.

Applications running in i5/OS PASE are integrated with the i5/OS integrated file system and DB2 Universal Database™ for iSeries. They can call (and be called by) Java and Integrated Language Environment^® (ILE) applications. In general, they can take advantage of all aspects of the i5/OS operations environment, such as security, message handling, communication, and backup and recovery. At the same time, they take advantage of application interfaces that are derived from AIX interfaces.