Can Leopard partition a backup drive with Tiger on it?

Question

I am going to be upgrading tp 10.5.4 on my main HD. I've cloned my whole 10.4.9 system to a 2nd internal drive a while back, but did not create a small partition for a SuperDuper Sandbox at that time. To save myself the time it will take to format the backup drive, partition it, then reclone my Tiger system can I...once I successfully upgrade to Leopard, use Leo to put a small partition on my backup HD, with Tiger on it, WITHOUT erasing the backup drive?

Answer 1

Karen,
First, and just to clarify things, your drive is already partitioned. It just has a single partition. In the "Partition" tab of Leopard's Disk Utility, you'll see a graphical representation of that partition (just as you would in earlier versions of Disk Utility). The difference is that there will appear a re-sizing "grab tab" at the bottom-right of the icon that represents your current partition (it looks just like the "grab tab" at bottom-right of any application window).
If we are simply re-partitioning a drive, we can choose a new partition scheme using the appropriate pull-down menu, and that scheme will be reflected in the graphical representation (showing however many volumes, aka "partitions" we choose), and they can be adjusted for size. At some point, we would click "Apply" to begin re-partitioning according to our settings. In this scenario, any and all data on the drive would be destroyed.
In your case, however, you'll be dynamically adding a partition to a "live" drive. You'll start by using the "grab tab" to make the one existing volume smaller, by however much space you want to allocate to the volume you'll add. Next, you'll use another new feature in Leopard's "partition" pane, the "+" button below the representation. This adds a new volume in the unallocated space you will have provided by making the first volume smaller. Click the "Apply" button, and your changes will be written to the drive (cross your fingers). Provided all works as intended, whatever data exists on the first volume will not be affected.
With 121 GBs free, you can theoretically create a second volume of 121 GBs. However, I wouldn't expect this to happen in practice. Some of that 121 GBs of free space will actually exist "in the spaces" between the data/files already written to the drive. How much of your free space exists in this state depends entirely on how you have been using the drive, for how long, and the file sizes involved. If, for example, you have ever filled the current single volume entirely, it is likely that some files reside near the end of the drive, with almost all of your free space "in the middle." In this case, Disk Utility will balk at allowing you to make that volume smaller.
Since you have recently "cloned" Tiger to this drive, it is reasonable to assume this won't be the case for you (the drive was probably erased at the time, right?). So, I think you have a good chance of success. And, since you have everything backed up on optical media, convenience will be the issue, not data security.
Scott