Move a file between partitions without copying

Question

Move a file between partitions without copying

Greetings! I think I know the answer to this, which is no, but i figured it's worth a shot.

I've got my 750GB internal HD partitioned (moving data from one OS install to an empty partition for use as my SSD media location, will eventually dissolve partition) and I don't really want to copy all the data from one partition to the other. Anything that I don't know, or, just gotta do it.

I literally want it to take three seconds. I know theres a command where it "moves" as opposed to "copies" but it still has to duplicate, and that's what im trying to avoid. its on the same hard drive! I don't think it can be done.

thanks.

MacBook Pro, Mac OS X (10.6.8), 2.2QC AG 8GB DDR3, 120GB Vertex3

Posted on Jul 19, 2011 12:33 AM

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Answer 1

Jul 19, 2011 12:54 AM in response to turtlemonkeys

...but it still has to duplicate, and that's what im trying to avoid. its on the same hard drive!

Your hard drive is partitioned, and from your description you want to move an item from one partition to another.

For just about everything that does not involve Disk Utility, the OS treats every partition as a distinct mounted volume, the same as if it were a separate drive. Although two volumes may be (and often are) physically on the same hard drive, the OS does not view it that way - it views each partition as a separate volume, the same as if the two partitions were two separate drives.

So, there's a couple of choices to get to the end result you want -

1) Drag and drop the file into the second partition, wait for it to be copied, then manually delete the original.

2) Hold down the Command key while dragging and dropping the file into the second drive. This will copy the file onto the second partition, then delete the original file for you. The result is a "Move" rather than a "Copy", even though copying it to the second partition is part of the process.

*****

Personally, I'm old school and not all that trusting. I prefer to drag and drop a file into another volume, resulting in it being copied there and leaving the original on the source volume. This allows me to confirm the success of the copying (verify the copy) before deleting the original.

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Answer 2

Ingo F.

Level 4

1,804 points

Jul 19, 2011 12:35 AM in response to turtlemonkeys

Short answer: Not doable.

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Answer 3

Ingo F.

Level 4

1,804 points

Jul 19, 2011 12:38 AM in response to turtlemonkeys

Long answer: The "3 second copy" works when you move a file on the same partition. Why is that so? Because every partition does have something called the TOC, the table of contents. This TOC describes where a certain file can be found. It's like a directory, telling you file A can be found at sectors 10, 11, 23, 25, 64 of the partition. So, the fast move works because all that is changed in a file move is the directory entry in the TOC. The file itself is never being touched.

And that's also the reason this cannot work if you transfer a file from one partition to another. All the data has to be written. And that just takes a while 😉

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