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I realise it is the default for external drives but not sure about other partitions on a users system drive. I don't have separate partitions on my machine so I can't look for myself ;-)

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up vote 0 down vote accepted

From OS X Support Essentials 10.6: "The Mac considers any locally mounted volume that is not the system volume to be an external volume. Thus, other partitions on your internal system disks will still be considered external volumes."

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Thanks Harv, appreciated. – Visitor82 Feb 23 '11 at 9:06

I only have an NTFS partition next to my HFS+ partition, so I can't verify this. But all my external's have "ignore volume ownership" disabled and I'm pretty sure I didn't set those.

Why do you need to know this? It's hard to help without some background information.

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Thanks deiga, I'm asking just to learn, I don't have a problem to fix. Next time I'm setting up a network for someone and it has a non system partition I will need to consider other users being able to access it. It's one of those bits of knowledge I couldn't explore for myself so I was hoping someone knew. – Visitor82 Feb 23 '11 at 9:04
Well I know that much, that I can access my Mac OS drive contents from my Bootcamp windows, don't know if it has anything to do with these permissions. – deiga Feb 24 '11 at 6:25

I haven't tested this properly, but my impression is that it defaults to respecting ownership on internal drives (including additional partitions on the boot drive), and ignoring ownership on external drives. I do not know exactly how it makes the distinction. My guess would be that it's based on whether the drive was present at boot, or attached later, but I could easily be wrong about that.

In any case, the default can be changed with the Finder's Get Info window, or the diskutil or vsdbutil commands.

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