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Mount a Windows partition of an optical disc on OS X

Today I needed to install some software on a Windows server – the software only came on an optical disc and the Windows server didn’t have an optical drive.
“No problem” I thought to myself, I’ll just put the DVD in my Mac and copy the files over, how difficult can it be?
As it turns out, when an optical disc has an HFS filesystem layer on it, the Mac will ignore the underlying ISO9660, Joliet and Rock Ridge extensions and head straight to what it knows best – and this is usually exactly what you want.
It is possible however to burn discs with a completely different set of files for Windows and OS X, and rely on the fact that the Mac will ignore the Joliet extension if there’s an HFS extension whereas Windows doesn’t care about the HFS extension and will happily show you the files on the Joliet extension.

Fortunately, there’s a way around this.

Insert the disc, head over to Terminal and type:
This will show the mounted filesystems – you’ll see something like this:

[kai@Hobbes ~]$ mount
 /dev/disk1 on / (hfs, local, journaled)
 devfs on /dev (devfs, local, nobrowse)
 map -hosts on /net (autofs, nosuid, automounted, nobrowse)
 map auto_home on /home (autofs, automounted, nobrowse)
 /dev/disk2s2 on /Volumes/ArchiCAD 18 (hfs, local, nodev, nosuid, read-only, noowners)

Unmount the optical drive (you can’t just select it and hit eject because it will be physically ejected)

sudo umount "/Volumes/ArchiCAD 18"

Make a temp directory to mount the disc on

mkdir /tmp/AC18

Then mount the disc, but tell the system to ignore any extended attributes and the Rock Ridge extensions

sudo mount_cd9660 -er /dev/disk2 /tmp/AC18

Finally, open the mounted disc window in the Finder

open /tmp/AC18

When you’re done, you can then unmount the disc:

sudo umount /tmp/AC18

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