2

I have an external hard drive that I'd like to use with both Mac and Windows. I want to avoid the ._ file issue (see Removing ._ Files from Non-Mac OS File System In Dropbox)

What filesystem can I format the HD to that supports extended file attributes (and thus avoid the ._ files) and is compatible with both Mac and Windows without use of additional drivers or whatever?

I know there are a ton of questions about filesystems for sharing among Mac/PC. I specifically want to know which are compatible but additionally support extended file attributes.

Thanks

  • Why is linux among your tags? Do you also need compatibility with this? – AFH Mar 1 '18 at 16:30
  • You can disable the _ files for the usb, google for "DSDontWriteUSBStores" for details. Why you need extended attribs? – uDev Mar 1 '18 at 18:07
  • @uDev I don't know if I need them. I definitely don't want them, at least for this drive. – zundi Mar 1 '18 at 20:30
  • @AFH You're right. Removed the linux tag. – zundi Mar 1 '18 at 20:31
  • You should look at this link. – AFH Mar 1 '18 at 21:10
1

Nothing meets all your criteria. The only filesystems macOS reads and writes out of the box without doing the ._ AppleDouble files are the Apple-proprietary HFS+ and APFS filesystem families. Windows does not read and write either of those filesystems out of the box.

0

The macOS operating system includes the dot_clean command, which can be used to remove the dot files from a FAT32 or ExFAT formatted drive partition. I consider the work needed to periodically run this command is about the same as emptying the trash.

For example, if my external drive is named MYEXTUSB, then I could use the command shown below to remove the dot files.

dot_clean /Volumes/MYEXTUSB  

Appendix

The dot_clean man page from macOS 10.13.3 (High Sierra) is given below.

DOT_CLEAN(1)              BSD General Commands Manual             DOT_CLEAN(1)

NAME
     dot_clean -- Merge ._* files with corresponding native files.

SYNOPSIS
     dot_clean [-fmnsv] [--keep=[mostrecent|dotbar|native]] [dir ...]

DESCRIPTION
     For each dir, dot_clean recursively merges all ._* files with their cor-
     responding native files according to the rules specified with the given
     arguments.  By default, if there is an attribute on the native file that
     is also present in the ._ file, the most recent attribute will be used.

     If no operands are given, a usage message is output.  If more than one
     directory is given, directories are merged in the order in which they are
     specified.

OPTIONS
     -f      Flat merge.  Do not recursively merge all directories in the
             given dir.  This is off by default.

     -h      Help. Prints verbose usage message.

     -m      Always delete dot underbar files.

     -n      Delete dot underbar file if there is no matching native file.

     -s      Follow symbolic links.  This will follow symbolic dot underbar
             files when they are found.

     -v      Print verbose output.

     --keep=mostrecent
             The default option.  If an attribute is associated with a data
             fork, use that.  Otherwise, use information stored in the Apple-
             Double file.  Note that the native fork's data is preferred even
             if the data in the AppleDouble file is newer.

     --keep=dotbar
             Always use information stored in the AppleDouble file, replacing
             any extended attributes associated with the native file.

     --keep=native
             Always use the information associated with the data fork, ignor-
             ing any AppleDouble files.

EXAMPLES
     The following is how to do an dot_clean merge on the mounted volume test,
     always using the dot underbar information.

           dot_clean --keep=dotbar /Volumes/test

DIAGNOSTICS
     The dot_clean utility exits 0 on success, and >0 if an error occurs.

BUGS
     None known.

BSD                              Sept 27, 2012                             BSD
  • The man page says dot_clean recursively merges all ._* files with their corresponding native files. Doesn't this imply that the original file would be modified? Not sure that's what I want. – zundi Mar 3 '18 at 21:39
  • If the external drive is FAT32 or ExFAT formatted, then the information stored in the ._* files can not be merged. Instead, the ._* files are deleted. I guess this is not clearly stated in the man page. – David Anderson Mar 3 '18 at 22:33
  • Would these *_ files be generated again later? – zundi Mar 4 '18 at 22:50

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