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View Full Version : APM vs GPT Partionining Issue???


jimmymac_4
03-02-2008, 12:03 PM
I'm a retired IT professional with 35+ years of experience. Although I am Windows proficient, I am new to the MAC. I have a new Intel/Leopard based iMac. It is my understanding that the proper hard disk formatting for this particular computer is GPT (GUID Partition Table) as opposed to APM (Apple PartitionMap). I have a double backup scheme in place with two separate external firewire drives. System Profiler indicates that my Time Machine hard disk has GPT (GUID) partitioning, but my Super Duper Hard disk has APM partitioning. I would have expected that a clone of my internal (boot) drive would have produced a GPT (GUID) clone/copy. I thought that I initially partitioned my Super Duper backup drive as GPT (GUID), so I am baffled by what I have just discovered.

1. Why would my Super Duper clone (backup) have APM partitioning?
2. Is this any cause for concern?
3. Since I already have Time Machine in place and my iMac appears to be stable, should I just repartition (zero) my Super Duper drive and start from scratch?

Thanks in advance.

dnanian
03-02-2008, 12:14 PM
1. Because we copy volume to volume, and don't look (or copy) the partition table.
2. In general, no, but if you have the opportunity I'd repartition as GPD/GUID.
3. If you're comfortable with the TM backup, sure.

jimmymac_4
03-02-2008, 12:47 PM
Dave,

Well that was a surprisingly rapid reply. Instinct told me this was the was to proceed, but I wanted confirmation. From what you indicated, it would appear then that I must have inadvertently partitioned the drive incorrectly. That will be rectified shortly. Thanks much.

jimmymac_4
03-02-2008, 03:43 PM
Hard disk repartitioned ... drive re-cloned ... alls' right with the world. Perhaps a nice future feature would be source/target partition detection with a warning messaged issued (and perhaps a brief word of advice) should the partitions differ ... just a thought.

Mactavish
03-02-2008, 09:33 PM
Hard disk repartitioned ... drive re-cloned ... alls' right with the world. Perhaps a nice future feature would be source/target partition detection with a warning messaged issued (and perhaps a brief word of advice) should the partitions differ ... just a thought.

Good point, I made the "mistake" of cloning to a Apple Partition HD, of a Leopard system on a GUID HD, all the four HD's in my MacPro tower are GUID formatted SATA II drives. What was odd or fun, is the cloned HD actually booted even though it was the wrong format for the drive. While it did boot is was mostly useless, making me do more homework, and then I discovered my mistake. With all the new hardware and software it's amazing any of this stuff works at all.

You have PPC computers, with Tiger and Leopard,
you have INTEL computer with Tiger and Leopard,
and HD's both internal and external with different formats,
not to mention much older stuff, Panther, Jaguar, etc.
and now I've added a BootCamp partition which needs separate Windows or Mac software to backup, and that's just to mention a few of the many variations. Dnanian and staff do a great job, and I'm sure they will keep updating as they find more issues with 2.5. I still prefer it over the "free" CCC cloning tool.