The POSIX program interfaces are available in addition to the BS2000 program interfaces. As a result, pure BS2000 programs, pure POSIX programs and merged programs can be executed. Merged programs contain both BS2000 and POSIX program interfaces, and are subject to certain restrictions (see "Restrictions for programs with merged functionality").
Figure 19: Pure and merged applications
POSIX program interfaces contain C library functions with BS2000 and POSIX functionality. Programs written on other platforms (UNIX, Windows, ...) in accordance with the XPG4 standard need only be recompiled in order to be executable in BS2000.
POSIX files can be accessed via pure or merged programs and can also be processed by some BS2000 software products, such as EDT and HSMS (see chapter “BS2000 software products in the POSIX environment”).