Re: Q: shared libraries

guest writes: > 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. Well, I have read articles claiming that static versions of these programs in fact tend to reduce overall memory consumption due to shared text. And because an application only will have the data it is actually _using_ from its libraries. Also startup times could well be reduced by using statically linked versions of programs. I guess this can be implementation dependant. > > 3. upgrading/patching (PIC)libraries without affecting applications(i.e. > without relink the applications). This is a valid point. > > 4. extending application by users(such as loadable extending C-code SQL > functions in Informix Univerisal Server and Postgres95, etc.). This will become more important in the future, I am sure. -- 'yvind Gjerstad Systems dept Tollpost-Globe AS N-6301 'ndalsnes/Norway E-mail: ogj@it.tollpost.no Phone: +47 7122 6663 Fax: +47 7122 6694