/Library and /System/Library

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Level 1

2 points

/Library and /System/Library

As I understand it, the reason to have these two directories came over from Next, which had /NextLibrary for library-type stuff that NeXT provided and where the user was not supposed to put stuff, and /LocalLibrary for library-type stuff the user provided and where NeXT did not put stuff, and the two got searched together. This was useful as it, e.g. allowed the user to keep a copy of /LocalLibrary when migrating to another machine or reinstalling the OS, or to keep /LocalLibrary on a separate disk partition etc. Apple eventually renamed these two directories /System/Library and /Library.

But it seems that Apple now breaks this agreement and installs all manner of things in the "user" library area "/Library". So why keep a separate /Library and /System/Library - is there still any difference in semantics between the two directories?

And is there still any mechanism equivalent to /LocalLibrary where I can put a hierarchy of directories equivalent to that under /Library and which is searched together with it?

iBook G4, Mac OS X (10.4.10)

Posted on Nov 27, 2007 2:59 PM

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Answer 1

etresoft

Level 9

56,644 points

Nov 27, 2007 3:19 PM in response to Dr. T

Aren't you forgetting one?
/System/Library
/Library
~/Library

There are three.

I think anything in /System is essential for system operations. Things in /Library are owned by root but shared by all users. Things in ~/Library are owned by a user and usable only by that user.

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Answer 2

Jun T.

Level 4

2,191 points

Nov 27, 2007 9:44 PM in response to Dr. T

As etresoft writes, you can put your own Fonts, Frameworks etc. into ~/Library/.

For more info, see Apple's document "[File System Overview|http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSyste m/index.html]", especially the first chapter "[File-System Domains|http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSystem /Articles/Domains.html]".

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Answer 3

Nov 28, 2007 6:51 PM in response to etresoft

This is correct. The thing to remember is that /System/Library ought not be messed with. It is reserved for use by Apple and changing anything there can break things.

Both /System/Library and /Library are global. /Library is where you can put global customizations that are available to all users.

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Answer 4

Dr. T Author

Level 1

2 points

Nov 29, 2007 12:59 PM in response to Dr. T

OK, this is what I was able to do on a NeXT:
- /NextLibrary - system library, reserved for O.S. vendor, user not to touch
- /LocalLibrary - sys.admin.'s additions to the library, computer-wide, O.S. vendor not to touch
- ~/Library - user's addition to the library, sys.admin and O.S. vendor not to touch.

Search order = ~/Library, /LocalLibrary, /NextLibrary.

The point is, I could be sure that /LocalLibrary applied system-wide, and was not touched by the O.S. vendor, so I could keep it on a separate partition, back it up, and I could erase and reinstall the O.S. without worrying about my local customizations in /LocalLibrary (and /LocalApps etc. etc.).

Now on my Mac OS X, I am doing the same but it's very awkward - the /LocalLibrary is still on a separate volume but I have to re-create symbolic links into /Library for each individual bundle in /LocalLibrary. Is there some sort of equivalent functionality in Mac OS X?

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Answer 5

etresoft

Level 9

56,644 points

Nov 29, 2007 2:23 PM in response to Dr. T

I don't know if that sort of thing is workable in MacOS X. The OS, of course, still supports it. But there are way too many people writing software who aren't aware of such things being possible. You know this is happening when you try to replace some directory with a symbolic link and some software installer blows away your link because it wasn't a directory.

On MacOS X, you just don't have that level of freedom that other UNIXes provide. You have to leave the system-level filesystem organization as it is. I used to have swap partitions, home partitions, etc. but just gave it up. It wasn't worth the hassle.

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Answer 6

Dr. T Author

Level 1

2 points

Nov 30, 2007 2:39 AM in response to Dr. T

Is there any way to serve /Network/Applications and /Network/Library from Mac OS X (Client), or do I need Mac OS X Server for that? Perhaps I could limp along with that as a substitute for the /Local domain - all my network machines use the same content of those anyway.

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