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I've installed Ubuntu 12.04 using the normal installer. Things having been working fine, but a few minutes ago I copied a 14Gb file and it said it had copied the file very quickly--so quickly I don't believe it. I was hoping that someone could give me some insight into what Ubuntu is doing here. Is it just making some sort of link to the file or perhaps continuing to copy the file in the background and not telling me? Thankyou :)

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up vote 4 down vote accepted

Generally you will see a progress bar if you use Nautilus to do the copy, however a key part of how Linux gets great disk performance is through disk buffering. At any time a large proportion of the available free RAM can be given over to disk buffering.

You can get some idea how this is working if you type


in a terminal window. Under the Column 'free' you will see three figures. The first is the actual free memory, while the second is the free memory less disk buffering. The third figure is of course free swap memory, which we are not really concerned with here.

If you are copying a file from one partition to another you should indeed see a progress bar and it should take an appreciable amount of time. An icon for it will appear immediately in the target folder (in Nautilus) however.

Another key point is that if you are actually moving a large file on the same partition then it really takes no time at all since only the logical pointers to the data need to be changed.

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Thanks - but it's not the same partition. I used the Ubuntu installer to mount a partition called Storage on a second internal HDD to /storage in the main Linux partition on the first HDD. So even though it looks as though it's on the same partition using Nautilus, it actually isn't. They don't even have the same file system (Storage uses NTFS so it works with Windows too). – Sman789 Aug 25 '12 at 20:32
It's the first part of fabricator4's thoughtful answer that applies to your case. Ubuntu and Linux really do rather extensive buffering; and your disk drive may to. If you enter the command sudo sync from a terminal you will see a delay in a case like this. When it comes back all of the written data is in the hands of the drive. – John S Gruber Aug 25 '12 at 20:35
Even though the drive is mounted within the file system, if it's on a different partition then it should still take an appreciable amount of time to perform the copy. In this case I would unmount the extra partitions out of the file system and verify that the file no longer exists (since the drive it is on is not mounted). It really does seem like you've moved a 12Gb file, not copied it to another partition. – fabricator4 Aug 25 '12 at 21:23

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