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I have a Mac laptop. I usually use Ubuntu Linux on it, but I want to start actually using Mac OS X. I want to have a volume that can be mounted read/write in both OS X and Linux.

I just upgraded to Snow Leopard, and while I did that, I created a new volume. Using Linux tools, I formatted the new volume to HFS (not HFS+). I then verified that Ubuntu would mount it, and that I could write to it.

Now that I'm booted back in to Mac OS X Snow Leopard, the volume automatically mounts, but only as read-only. And while I'm an expert in Linux I'm a total newbie in OS X.

How can I mount the HFS volume as read/write? How can I ensure that it will always mount read/write on every reboot?

I want to rename the HFS volume from "untitled" to "Mac Home". diskutil fails with a strange error ("Failed to rename volume: Invalid request (-9998)"). I suspect that the problem is that the volume is mounted read-only; if I can mount it read/write I hope this command will work. Or, if it is read/write, maybe I can rename it in the Finder?

Thank you for any help.

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up vote 1 down vote accepted

I got help from an expert Mac user. He recommended I just run the Mac GUI disk utility. Per his directions, I clicked on the magnifying glass icon in the upper-right-corner (Spotlight) and searched for "Disk Utlity", then ran it.

Disk Utility showed that the volume was supposed to be Journaled. When I used the Linux tool to write a new file system, the Linux tool didn't change the type the volume was supposed to be. Using Disk Utility I selected the volume, chose the "Erase" tab, then changed the Format to "Mac OS Extended" and then clicked on the Erase... button. When it was done, Mac OS X mounted the volume as read/write, and when I booted into Ubuntu, Ubuntu mounted the volume as read/write. Success.

So, to make a volume that is readable in both Mac OS X and Linux, use the Mac OS X Disk Utility to create the volume, and use "Mac OS Extended". (Linux cannot mount a journaled volume as read/write.)

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