Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!sdd.hp.com!mips!news.cs.indiana.edu!know!ladcgw.ladc.bull.com!hermes.ladc.bull.com!fmayhar From: fmayhar@hermes.ladc.bull.com (Frank Mayhar) Newsgroups: comp.unix.internals Subject: Re: Shared libraries are not necessary Keywords: ISC i386 shared libraries Message-ID: <1991May20.214252.7449@ladc.bull.com> Date: 20 May 91 21:42:52 GMT References: <162@titccy.cc.titech.ac.jp> <7690@auspex.auspex.com> <169@titccy.cc.titech.ac.jp> <7762@auspex.auspex.com> <184@titccy.cc.titech.ac.jp> <1991May16.002617.15386@ladc.bull.com> <196@titccy.cc.titech.ac.jp> Sender: usenet@ladc.bull.com (Usenet News) Reply-To: fmayhar@hermes.ladc.bull.com Organization: Bull HN Information Systems Los Angeles Development Center Lines: 73 Nntp-Posting-Host: hermes.ladc.bull.com In article <196@titccy.cc.titech.ac.jp>, mohta@necom830.cc.titech.ac.jp (Masataka Ohta) writes: -> In article <1991May16.002617.15386@ladc.bull.com> I write: -> >Again I ask, what do you consider a "right" way to implement them? As opposed -> >to what you consider a "wrong" way. Ignore existing implementations. I mean, -> >in the best of all possible worlds, how should shared libraries be implemented. -> >(And don't say that in the best of all possible worlds, shared libraries -> >wouldn't exist. See the last paragraph, below.) -> -> I say, in a good world, shared libraries shouldn't exist. Go back and reread what I wrote. You're copping out. -> Because, in a good world, unless someone proof something is really -> necessary, it shouldn't exist. OK, then, I have a counterargument: Computers aren't necessary. You can do just as well (albeit somewhat more slowly) using pencil and paper. After all, people got by without computers for thousands of years. Define "necessary." Are 1-gigabyte disks "necessary?" What don't you use a teletype, a CRT isn't really "necessary," is it? -> I have already proved that -> 1) its space saving is negligible I beg to differ. There is clear evidence that the savings, in both disk and memory, is significant. The larger the system, and the more users it has, the more significant the savings becomes. I'll let the statistics posted by Sean and Nick speak for themselves. Even with the overhead of such things as indirect jumps, there are still significant savings. -> 2) shared libraries dose not help software version up -> from /etc/hosts to DNS So what? And, in fact, in certain situations, it does. I was able to go from /etc/hosts to DNS by adding _one_ shared library to my Sun. And I didn't have to recompile or relink a _single_ program. I think that that's significant. And many other kinds of upgrades are made much simpler by using shared libraries. You can replace a single library instead of replacing dozens of applications. -> So, why you think shared libraries should exist? See above, and my original post. -> >In -> >other terms, such as ease of maintenance or disk or memory usage (given -> >that shared libraries' instruction space is sharable) it can be much -> >more efficient. This is the tradeoff. -> Some claimed that with examples. And, with their examples, I made -> measurement and investigation and proved they are wrong. So, there is -> no tradeoff, so far. Funny, I didn't see any sort of proof. I saw a number of flat statements, unsupported by data of any kind, but no proof. What is your proof that it saves neither disk space, memory, nor maintenance time? I challenge you to back up your assertions with real data. I reiterate: There is a tradeoff in the implementation of shared libraries between various forms of efficiency, e.g. runtime versus memory or disk savings, etc., but this certainly does not obviate the need for them. Like anything else with tradeoffs, there are arguments both for and against shared libraries. The thing to remember, though, for people in both camps is that while shared libraries are extremely useful in certain situations, they aren't always the best solution, in all cases. Of course, this is probably falling on deaf ears, as it appears that both this issue and the utility of windowing systems are religious issues to you. -- Frank Mayhar fmayhar@hermes.ladc.bull.com (..!{uunet,hacgate}!ladcgw!fmayhar) Bull HN Information Systems Inc. Los Angeles Development Center 5250 W. Century Blvd., LA, CA 90045 Phone: (213) 216-6241