Shared libraries in Tropix: a simple and efficient implementation

Abstract

During many years, the TROPIX Operating System had no shared library facility. As the time was mature to develop this feature, several other Operating Systems were studied, and we readily verified that the various used methods worked correctly, but were excessively complex. We wondered, then, if it wasn 't possible to develop a simpler technique, that also provided the good sides of all theses methods, with minimal disadvantages. Now we know that this is possible. In this paper we present a shared library method that reduces the disk storage and main memory spaces, reduces the load/execution time for a program, and the program runs at full speed. It also doesn't need special compilers/assemblers, doesn't use linkage tables nor needs dynamic link-editions. The only caveat is that if, during an upgrade of the library, one or more functions of the shared library grow over a certain (tunable) threshold, the executable files that reference the shared library must be relink-edited.