Re: Q: shared libraries

In <580mpu$tcj@nntp.idgonline.no> <Nils.Myklebust@idg.no> (Nils Myklebust) wrote: : The only tiny problem I have with shared libraries is the small added : management of making sure the shared libraries are available at : runtime. I have no experience on this, and it may be insignificant. : However so is the space we would save using shared libraries. Our : executables take up about 80 MB althogether, but that's insignificant : in itself with todays cheap disks, and particularly when you compare : to the typical database size we have. : I read this ten days after its posting. However, it seems you were speaking from last decade. If you didn't point out, I would almost forget shared libraries might have been partly used for saving disk space in stone age of this industry. Nowadays, have nothing to do with your reason of using shared libraries, most unix and database engine/server vendors and users supply and use shared library mainly for following reasons(far away from a complete list and likely to be wrong and bad as you may point out): 1. reducing duplicated job on loading identical program text/data/.. segments and thus speeding up the program startup. Please, think about if csh, ksh, bsh are built without using shared library. 2. reduce process size(not only program size). This will reduce the job (and speed up) of memory paging(or swapping on old system) as well as reduce the page consumption. Think about if informix server was built without using shared libraries and 100 process instances were spawned from it(typical db server text/data/.. segment size without using shared library will be 2 to 10 Mb). 3. upgrading/patching (PIC)libraries without affecting applications(i.e. without relink the applications). 4. extending application by users(such as loadable extending C-code SQL functions in Informix Univerisal Server and Postgres95, etc.). Of cause, with next century's cheap high speed cpu and ram, people will possibly not bother to use shared library for above reasons. -g