VMS/IRAF Installation and Site Manager's Guide
VMS/IRAF Installation and Site Manager's Guide
VMS/IRAF provides a shared library facility to reduce disk and memory
requirements. What the shared library facility does is take most of the
IRAF system software (currently the contents of the EX, SYS, VOPS, and OS
libraries) and link it together into a special shareable image, the file
s_iraf.e in the core BIN directory. This file is mapped into the
virtual memory of each IRAF process at process startup time. Since the
shared image is shared by all IRAF processes, each process uses less
physical memory, and the process pagein time is reduced, speeding process
execution. Likewise, since the subroutines forming the shared image are no
longer linked into each individual process executable, substantial disk
space is saved for the BIN directory. Link time is correspondingly reduced,
speeding software development. For the shared library to be effective, it
must be installed in system memory as described in
§8.2.