case-sensitive, journalied?

Discussion in 'macOS' started by zoran, Oct 13, 2013.

  1. zoran macrumors 68040

    Jun 30, 2005
    Iam installing Leopard and in the beginning there is this option, either "MacOS extended (journaled)" or "MacOS extended (case sensitive, journaled)". What exactly does that mean and what are the differences between those two?
  2. benwiggy macrumors 68020

    Jun 15, 2012
    The default file system is NOT case-sensitive. It is, however, case aware.

    So you can save a file called "WONKYdonkey", and it will be saved to the disk as such.
    However, you can't save a different file called "wonkyDONKEY" in the same folder. Attempts to do so will overwrite the existing file.
    The file system remembers case, but does not distinguish between them.

    If you use a case-sensitive file system, then you can have different files in the same folder with the same name, but different case.

    One reason for not doing so is that some software doesn't work in case-sensitive file systems -- particularly Adobe software -- because it assumes case-insensitivity.

    In short: you should use "Mac OS X, Extended, journalled".
  3. zoran thread starter macrumors 68040

    Jun 30, 2005
  4. benwiggy macrumors 68020

    Jun 15, 2012
    Unless you have very specific techy needs for that file system: you should not use it.
  5. zoran thread starter macrumors 68040

    Jun 30, 2005
  6. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    The Adobe issue is partially sloppy coding in how they use filenames that are part of the Adobe software.

    As for the OS X system disk, I think there are other issues around case sensitivity.
  7. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Just to add to the chorus... discovered last week while helping a forum member that case sensitive does not play nicely with Migration Assistant either. The user had some iTunes library folder on a case sensitive main drive and Migration Assistant refused to move them to a new machine.
  8. poiihy macrumors 68020


    Aug 22, 2014
    Why would you need a case sensitive file system? Why do they even give you that option?
  9. mfram macrumors 65816

    Jan 23, 2010
    San Diego, CA USA
    Historically, Unix filesystems have always been case-sensitive. My understanding is that there's some Java stuff that relies on a case-sensitive filesystem. Or if you're porting some other software systems originally written for Unix, it might require case-sensitivity.
  10. KALLT macrumors 601

    Sep 23, 2008
    I remember reading that case-sensitive file systems are simply more efficient (e.g. for querying directories) and this mattered many, many years ago, but not really anymore, at least not for most purposes. I assume that this is also where the convention of naming directories and files in lowercase comes from, to keep the system structure predictable.

    I suppose in OS X the option is there for compatibility. As Weaselboy touched upon, transferring files from case-sensitive to case-insensitive is a PITA. ‘/System’ and ‘/system’ can coexist on the former, but not the latter. A sloppy transfer will either ignore, overwrite or rename one of the two. A case-sensitive HFS+ volume is still better for compatibility with OS X than FAT or ExFAT, so it could be used as a transitory system.

    Apple has not disclosed yet whether they will make the switch to case-sensitivity with Apple File System, as that system is currently case-sensitive only.
  11. jerwin macrumors 68020

    Jun 13, 2015
    I've encountered unix tarballs that rely on case insensitivity. Don't recall the exact details. It may have been a file in all caps (INSTALL), with an directory named (install) containing various system specific stuff (install.VMS, install.SGI, install.CRAY, etc). Don't recall the exact details, though.

    It used to be that
    hello.c was a c file
    hello.h was a c header file

    hello.C was a C++ file
    hello.H was a C++ header file

    When you're used to working with case-sensitive file systems, I guess you can develop certain habits that don't work when someone a decade or two later ports the same code to MacOSX.

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