Hello, this is Jan Lehnardt and you're visiting my blog. Thanks for stopping by.
plok — It reads like a blog, but it sounds harder!
I bought a WD MyBook Pro II for my storage and backup needs. The 2x500GB RAID 1 setup provides enough space and safety for me. It is also faster than the internal 2.5” hard drive of my Intel Mac Mini and since Macs can be booted from Firewire drives I thought it’d be a good idea to do just that.
I went to install a fresh copy of MacOS X onto the new drive. The installer happily proceeded and upon reboot, well, the Mini didn’t reboot into the new system. The old installation came up. Easy, I thought, just set the correct Startup Volume in the Preferences. No Go.
Luckily, when holding the alt-key while starting up, a Mac shows all available volumes to start OS X from. Relieved, I chose the MyBook volume. A couple of seconds into the startup sequence, the screen turned grey, a console spilled weird characters all over the place and a message saying the Mac had crashed appeared. Neat! Some ACPI Driver was at fault, the spilled characters said. A bit of researching, re-installing and other tricks did not help. I even SuperDuper!ed my existing installation onto the new drive and all that changed was instead of the kernel panic a “No Startup Volume here”-screen popped up. *sigh*
I then went for dinner. It helps to get off a problem that doesn’t solve itself after a few tries. When I came back I went for a little more researching and found this little gem by Jonathan “Wolf” Rentzsch. It solved my issues.
The deal is: Intel Macs use a partition scheme different from PPC Macs. This is not an issue until you try to boot an Intel Mac from a PPC partition or vice versa. The utilities that come with MacOS X as well as the installer do a very bad job at hinting at this. Jonathan’s article does. It is a somewhat buried setting in the Disk Utility: Select the drive on the left (not the partition). Go to the Partition pane on the right. Click the Options… button on the bottom. A sheet pops up that allows you to select one of three partition schemes. The one for Intel Macs (GUID Partition Table), the one for PPC Macs (Apple Partition Map) and the one for PCs (Master Boot Record). Even this sheet fails to properly explain the consequences when it comes to booting your Mac from this drive.
After switching to the GUID Partition Table, I could erase the drive (again) and clone my existing drive over (again). This worked. If you have problems getting your Mac to boot from a Firewire drive, this might help you. Thanks to Jonathan Rentzsch for his in-depth explanation — the user manual that comes with the MyBook Pro II doesn’t mention any of this.
Very awesome! Thanks.
I’m bookmarking so when I get mine I can use it like this too. Coolness.
I have a western digital MyBook 500 FireWire external drive which is partitioned into 2 volumes using GPT.
I want to install OS X onto one of the volumes but the OS X installer doesn’t show the drive as a valid install destination.
Even though [when booted from the OS X install DVD) disk utility sees the ext drive the Installer doesn’t see it.
@Stephen Depending on you having an Intel or PPC based Mac you have to reformat that partition you want to install OS X on. For Intel Macs, as in my posting, you need to set the partition type to GUID. For a PPC Mac, you need to set the partition type to APM. When you did that, reformat your partition and install OS X as usual. Hope that helps.
wonderful information! thanks for the explanation effort. i have 500 WD FW and was stuck until i found your article.
I have the Home edition 1TB. It’s running on an iMac G5. I checked and the partition is set to Apple Partition Map, as it should be for a PPC. It shows in Startup Disk, but wont boot when chosen, nor does it show up when the opt. key is held down at startup.
Any suggestions ?