System i: Programming i5/OS PASE - IBM

Related concepts
“i5/OS PASE shells and utilities” on page 56
i5/OS Portable Application Solutions Environment (i5/OS PASE) includes three shells (Korn, Bourne, and
C shell) and provides many utilities that run as i5/OS PASE programs. i5/OS PASE shells and utilities
provide an extensible scripting environment that includes a large number of industry-standard and
defacto-standard commands.
Related reference
“Compiling your AIX source” on page 9
You can install one of the AIX compiler products that support installation in i5/OS PASE to compile your
programs in the i5/OS PASE environment.
i5/OS PASE as a useful option for application development
i5/OS PASE provides considerable flexibility when you are deciding how to port your AIX applications
to your system. i5/OS PASE is only one of several options you can use to port AIX applications. In
addition, under some circumstances, i5/OS PASE is not the best solution.
API analysis
Your starting point for determining whether an application is suitable for i5/OS PASE is an analysis of
the application: the APIs, libraries, and utilities that the application uses and how effectively the
application will run on the i5/OS operating system. For more information about how code analysis fits
into the procedures for porting applications to i5/OS PASE, see “Preparing programs to run in i5/OS
PASE” on page 8.
Characteristics of a potential i5/OS PASE application
Here are some useful guidelines that you might consider when making the decision whether to use
i5/OS PASE:
v Is the AIX application a highly computation-intensive application?
i5/OS PASE provides a good environment for running computation-intensive applications on the
i5/OS operating system by providing highly optimized math libraries.
v Does the application rely heavily on functions that are supported only in i5/OS PASE (or only
partially supported in ILE), such as fork(), X Window System, or pseudo-terminal (PTY) support?
i5/OS PASE provides support for the fork() and exec() functions, which do not currently exist on the
i5/OS operating system (except through the spawn() function, which incorporates the fork() function
with the exec() function).
v Does the application use a complicated AIX system-based build process or testing environment?
i5/OS PASE lets you use AIX system-based build processes, which are especially useful when you have
an existing, complicated process that is not readily transferred onto a new operating system.
v Does the application have dependencies on an ASCII character set?
i5/OS PASE provides good support for applications with these needs.
v Does the application do a lot of pointer manipulation, or does it convert (cast) integers to pointers?
i5/OS PASE supports both 32- and 64-bit AIX addressing models with low performance cost and the
ability to convert integers to pointers.
When i5/OS PASE might not be the best solution
i5/OS PASE is generally not a good choice for code that provides a large number of callable interfaces
that must be called from ILE and that has any of the following characteristics:
v Code that needs higher performance call and return than provided by either starting or ending i5/OS
PASE on each call or by calling an i5/OS PASE procedure in an already-active i5/OS PASE program
(using the Qp2CallPase API).
i5/OS PASE 5