Re-partitioning on MacOS X


Peter van der Linden, July 2003

Intro

Apple gave all the developers at the WWDC 2003 a copy of Panther (MacOS 10 version 3). So it would be great to install this on your system and try all the neat features, like expose. However, it is still a developer preview, so you want to make your system dual boot. That means setting up two complete partitions, and having MacOS 10.2 on one, and Panther on the other.

But what if you didn't create two partitions on your disk originally? How can you shrink the existing partition without losing any of the data, and create a second partition?

It turns out that shrinking an existing partition without losing all the data on it is not supported by MacOS. There is a commercial product at http://www.fwb.com/html/partition_toolkit.html. That's only for MacOS 9. Nothing I know of does this on MacOS X yet.

Approaches

There are 3 main approaches to re-partitioning, and they all involve backing up the data manually. The three approaches, in increasing order of risk are i) full backup, repartition, full restore, ii) backup using asr (apple system restore), iii) backup data, then fiddle around by hand.

Note carefully that all of these start with "back up the data on the partition that you want to split"!

  • backup, repartition, restore
    back up the data on the partition that you want to split. Run Carbon Copy Cloner to backup the partition onto a firewire drive as image (or as a volume, if you want to boot off it). Then boot from another disk or from CD, use Disk Utility to repartition the original disk, and restore the data.

    The other disk to boot from can be a freestanding firewire drive or almost any Mac with a firewire drive. Just boot it while holding down "T", and all of its volumes will be exported over firewire as if it was a big firewire drive enclosure). You can't do this with black and white G3's as they don't support the TDM feature of firewire.


    or Run NetInstaller app and set machine to net install. Once in installer switch to Disk Utility, repartition and install. Reboot in your new OS and clone onto your new partition

  • use asr to back up
  • edit by hand