What do dynamic linking and communism have in common?

http://blogs.sun.com/rvs/entry/what_does_dynamic_linking_and

by vinutheraj • 17 years ago

30 30 17 years ago

blogs.sun.com

jacobolus• 17 years ago

Yay for irrelevant analogies! Who cares if they shed any light on the topic whatsoever?! Let’s give red-blooded patriotic Americans something we can all get behind, hatred of the dirty commies!

You know what else dynamic linking is up to, Mandrake? Sapping and impurifying all of our precious bodily fluids.

pvg2• 17 years ago

Sometimes a catchy title is just a catchy title. Perhaps you've been so damaged by the misuse of this - actual dreadful, extended, fatuous analogies between one thing and something rather unrelated/inflammatory that you recoil at the mere sight. This is understandable but in this case, the author doesn't actually make any serious analogy with communism - just a passing reference to 'ideas that sounded good but didn't work out in practice' to get his critique of dynamic linking going. It's a harmless (albeit worn-out) device - it's you who might be red-bloodedly over-reacting.

scott_s• 17 years ago

If I am forced to take the mental effort to disentangle the actual argument from the irrelevant analogy, I'm probably going to save the effort and skip all of it.

protomyth• 17 years ago

Generally when I see article with really, really stupid analogies, I assume the article is not well thought out and probably of poor quality. As a rule of thumb, it gives pretty good results.

aminuit2• 17 years ago

"It is probably more illuminating to go a little bit further back, to the Middle Ages. One of its characteristics was that "reasoning by analogy" was rampant; another characteristic was almost total intellectual stagnation, and we now see why the two go together. A reason for mentioning this is to point out that, by developing a keen ear for unwarranted analogies, one can detect a lot of medieval thinking today."

Edsger W. Dijkstra

jfager2• 17 years ago

How is this reasoning by analogy? He makes the rhetorical comparison to communism, but his point doesn't depend on that comparison in any way at all.

aminuit2• 17 years ago

The rest of this article discusses why dynamic linking does not deliver on any of its promises and why, just as communism, it might be an idea that only works in an ideal world.

He depends on that comparison because the rest of his argument is lacking.

His first example, the one about the broken C++ ABI, isn't really an argument against dynamic linking. C++ binary compatibility has always been a nightmare because different groups refuse to agree on a standard. It's a ding against C++, but not dynamic linking per se. For any solution to the problem he's trying to solve, there are going to be pathological cases that perform poorly. Poor C++ ABI standardization seems to be one of those cases for dynamic linking.

He also doesn't really consider the world before DSOs. Consider maintaining a machine (or lots of machines) where every package was statically linked against different versions of the same core libraries. What happens when a vulnerability is discovered in one of those libraries? How do you know which packages are vulnerable? Do really want to upgrade every single package on every machine if there is a libc vulnerability?

netsp• 17 years ago

Irony

ubernostrum2• 17 years ago

Really?

Guess he must've read different editions of all those medieval philosophers than I did.

philf• 17 years ago

Which medieval philosophers are you referring to?

alecco• 17 years ago

Libraries also open up a gate to exploits. For example the return to libc technique.

http://en.wikipedia.org/wiki/Return-to-libc

astine• 17 years ago

Pfft. Dynamic Linking isn't broken, Solaris is. For some reason I don't have nearly the same amount of trouble handling dynamic libraries on Linux or BSD as I do on Solaris. If code depends on bugs, then the code is broken and that is a bug. Packaging your own special version of a library may solve your problems in the short term, but it increases maintenance in the long term. This is the same whether you do it statically or dynamically.

modeless• 17 years ago

OK, the analogy is dumb, but the point stands on its own. Dynamic linking has been around for so long that it's a sort of dogma, never questioned. Of course you do dynamic linking!

Just step back and consider all the problems dynamic linking has caused us (DLL hell, package management headaches, C library incompatibilities, various ABI issues) and the sheer complexity of the systems invented to solve those problems (Side-by-Side assemblies; InstallShield, Windows Installer, and umpteen other install frameworks for Windows; LD_LIBRARY_PATH, ldconfig; APT, RPM, and umpteen other Linux package managers).

chrischen3• 17 years ago

Yes the analogy is dumb. Also unregulated capitalism is just as bad as pure communism. Just as that one eastern country with a communist government had to loosen it's economy, that one western country (which is doing better than that one eastern country) had to restrict some of it's capitalism.

lupin_sansei4• 17 years ago

I used to think that too, but the data seems to show that more economic freedom (unregulated capitalism) the better off the people are (per capita GDP, etc)

http://commons.wikimedia.org/wiki/File:GM_-_Countries_by_Eco...

http://images.absoluteastronomy.com/images/encyclopediaimage...

If unregulated capitalism was just as bad as communism you'd expect this chart to have a bell curve type shape, rather than it's upward curve: http://www.investmentu.com/wp-content/uploads/2008/02/200601...

You can explore the relative economic freedoms of each country here: notice that the US is only the #6 free-est economy in the world): http://www.heritage.org/Index/Ranking.aspx

abecedarius• 17 years ago

Couldn't you get the space efficiencies without the incompatibility headaches by naming the library like libfoo-SHA1_AS_LONG_HEX_STRING.so in addition to libfoo.so.1.2.3? They're already using symlinks in the lib directories.

wmf• 17 years ago

This assumes that libraries are fully parallel-installable, which is often not the case in Unix. I think .NET does something like this, though.

lisper• 17 years ago

There's a simple counterexample to this argument: operating systems. If it were not possible to create shared code, it would not be possible to write operating systems, which are nothing but shared code. Shared code does demand more careful management and versioning, especially of interfaces, and if you don't do that you are indeed hosed. But if you do then you aren't.

RyanMcGreal• 17 years ago

They're both supported/opposed fanatically by ideologues?

pedrocr• 17 years ago

There are clearly downsides to dynamic linking but static linking would fail spectacularly when there is a bug in a common library, like libc. One of two things happens:

- Some applications are not updated and retain the bug. Extremely dangerous if it is a security bug.

- Suddenly your package manager needs to update almost every single application on your system. All the packages in my Ubuntu system is a total of ~1GB. Now that you statically compiled them prepare for a very long download.

The problems presented are largely solved in integrated distributions (like Linux distributions or Apple software). Where this isn't as clear is when external parties are trying to distribute software in a non-coordinated way (most apps in Windows, non-Apple apps in OSX). In those cases static linking probably makes sense but even then I'd say you are better off linking dynamically to fairly standard stuff like libc.

wingo• 17 years ago

zlib security vulnerabilities, anyone? Or gecko, for that matter...

ilyak• 17 years ago

Dynamic linking works just fine. You don't want your every app to carry its bits of glibc inside, same for libx11, same for openssl. And it's definitely more polished than gems or jars or whatever other languages have; maybe only perl/cpan comes close.

On other hand, C++, with its writhing ABIs and changing mangling rules is definitely not suited for dynamic linking.

They could make their Class.forName() one day, but they were too arrogant and now it would never work okay. The solution is to restrict C++ usage.

What do dynamic linking and communism have in common?

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