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TICKET ARCHIVE -> Installing Mac OSX on external drive

fpayne - Jun 9, 2007 - 4:59 pm

I would like to install Max OSX on my external LaCie 500GB external fire wire Drive. There is already data on the drive which I do not want to lose.

Can I partition the drive without losing the original data (using normal backup security) and install MacOSX on a partition solely for the purpose of maintenance, i.e Disk Warrior or defragmentation software.

If so, can I use Disk Utility for the partitioning or do you recommend another program.

Thanks

DeltaMac - Jun 10, 2007 - 7:55 am

You can install OS X on the external drive without needing to partition the drive. Just install, choosing that drive as the destination drive.

there's not usually many good reasons for multiple partitions with modern operating systems.
Why do you want to partition the drive first? The best way to do that is to erase the drive - and you lose everything that you don't have backed up in another way.

- Dale

fpayne - Jun 10, 2007 - 11:08 am

Thanks very much.

The reason for wanting to partition first was after all my years of experience with Windows, when my hard drive was partitioned with one partition for operating system and programs with all data on the second partition. With the number of crashes that came with Windows, data on a separate partition was always a good plan.

Regards

Frank

DeltaMac - Jun 10, 2007 - 2:57 pm

Just my opinion - it's time to break that habit! As I said, modern operating systems generally don't have the need for multiple partitions. Windows isn't quite there, yet.
There's nothing wrong with having multiple partitions, but you do need to erase the drive to do that.
iPartition can change the format and add a partition without formatting, but there's always some risk in modifying the drive partitions, and always recommend erasing when you want to make a major change like that.
The new file system (ZFS) that Apple should be using with Leopard should also help out with something like this. As I understand it, you won't need to partition any drive.
- Dale

fpayne - Jun 10, 2007 - 5:35 pm

Thanks very much. I soon realised how much better MacOSX was than Windows. I am looking forward to Leopard coming out.

As an aside, what about putting the Intel and PPC versions of OSX on the same external drive. I have a Power Book and Mac Book Pro which I would like to maintain.

Thanks again

DeltaMac - Jun 10, 2007 - 9:02 pm

A PPC install, and an Intel install of OS X use a different partition structure. I have heard it can be done, but is not simple. You will notice that there is no commercial installer available for Intel Macs, like there is for PPC Macs. Perhaps that will be another benefit of Leopard when it comes out, as there should be a universal installer
- Dale

fpayne - Jun 11, 2007 - 3:29 am

I thought it might be a problem.

Thanks very much for your help

Regards

Frank

fpayne - Jun 17, 2007 - 9:15 am

Hi again,

Ok so I tried to install OSX on the Lacie external 500GB firewire drive, but a message came up saying it could not be installed as te drive does not support OSX. It is formatted to Mac OS Extended and already has some data on it.

Any ideas or is the existing data the problem. It is connected to the Firewire 800 port on a 17" MacBook Pro Core Duo

Thanks

DeltaMac - Jun 17, 2007 - 5:42 pm

The existing data is the problem. Not the data, itself, but that your hard drive is formatted with the wrong partition scheme (Apple Partition Map). This makes no difference if you simply use the drive for data storage, but because you now want to use the drive to boot your Intel Mac, your drive must be formatted with the GUID Partition Table. So, the installer reports that your drive does not support OS X.
You would be OK on a PPC Mac, and if you had originally formatted this on your Intel Mac, it should have defaulted to the correct partition scheme. You must have originally set this up on a PPC Mac, like your PowerBook? You can manually choose either one at the time of formatting. You will need to backup the data on the external drive to change the partition scheme. AFAIK, even if you add partitions, they maintain the original partition scheme.
AFAIK, there is no way to change that without reformatting the hard drive. You can check what you have (for certain) by opening Disk Utility, click on the hard drive info line (showing the manufacturer's info), and click on the partition tab, then click on the Options button. Select GUID, then OK, then click the Partition button (AFTER backing up your data, since you will lose everything on the drive with this process.)

You could proceed by installing OS X while connected to the PowerBook, but you will not be able to boot the Intel MacBook Pro from that drive.
- Dale

fpayne - Jun 18, 2007 - 6:41 am

The drive has only ever been connected to the Intel Mac Book Pro. I don't remember formatting it, but I guess I must have and still not being that familiar with Macs (15 year PC man)probably chose the partition table I had heard of. No doubt I saw the drive of the Mac Book said Mac OS Extended so I chose that for the external drive as well.

I can find an older external USB drive to back up the data and reformat the drive. As most of the work is done on the Intel machine, the Power Book will have to stay as it is :-(

Thanks again for your help

fpayne - Jun 19, 2007 - 3:51 am

So far so good. OSX is on the drive and the computer boots from it.

I have tried to look but cannot find an answer, is there a way to give you an option on start up of which drive to boot from. At the moment it defaults to the external drive, which is not what I want. The simple solution ia to unplug it while booting up, but a boot menu would be nice:-)

Thanks

fpayne - Jun 19, 2007 - 4:33 am

An update.

I found out how to make the Macintosh HD the start up disk through system preferences which makes life easier, but a booy menu would still be nice.

Regards

Frank

DeltaMac - Jun 19, 2007 - 1:22 pm

There is a boot menu. Restart, and hold the Option key. You will get a grey screen showing all available boot volumes. Use an arrow key, or tab, or click on the device with your mouse, then press enter.

You can always shoose a different boot device this way.
Or, it simply boots to whatever you have already selected.

- Dale

fpayne - Jun 19, 2007 - 2:07 pm

Thanks very much. That's perfect.

Kind regards

Frank

fpayne - Sep 29, 2007 - 11:45 pm

Sorry to be a pain in the backside, but .........
I have now traded in the PowerBook for a Core 2 Duo MacBook Pro so I now have that as well as the Core Duo MacBook Pro and I am back to the same problem. The external drive can only be used to boot the older machine and not the newer Core 2 Duo.
I assumed, obviosly wrongly, that as both were now intel I would be able to start either from the same version of OSX. 10.4.10 on both the internal and external drives.
Is there around this problem or can it only be done if the two processors are the same
Thanks again
Frank

DeltaMac - Sep 29, 2007 - 11:55 pm

Boot to your system restore disk from the newer MBook Pro, while the external harde drive is connected, and reinstall just the system without the rest of the bundle. At the screen where you choose a drive, select the external, and then click on the Options button. Choose the Archive and Install choice. Click continue, and then click the Customize button, and unselect the items that you don't need to reinstall, such as the bundled software (unless you want to also install those apps). After the install, your external _should_ be able to boot either system.
- Dale

fpayne - Oct 1, 2007 - 9:28 am

Sorry about the delay in responding. It took me a while to get round to checking the second machine.
The fix worked fine thanks, Both laptops are now booting from the external disk.
Thanks again and kind regards

Frank