On Monday, November 28, 2016, Py <py@luyten.fr> wrote:



>>> Have you ever made Nautilus copy/move a huge directory tree and then
>>> started a similar task for other directories while Nautilus was
>still
>>> working on the first task?
>>
>> A directory containing 10,000 1MiB files moved to another directory
>> completes immediately. Copying takes a while, as expected, and
>multiple
>> copies has the behavior you describe.
>>
>An SSD drive might not have this problem, but a spinning disk
>definitely
>will.  You should never try running multiple copies on the same disk if
>
>you want it to finish in a reasonable time.  With one copy, you can do
>long contiguous reads and writes, but if you have multiple copies
>happening, the read and write head will be bouncing all over the disk.
>________________________________________
So ideally this is the file manager job to queue copy operations. This allows to do right even when the user is wrong, or wants to launch big copy before coffee.
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No. The kernel (io scheduler) is supposed to order requests to avoid this scenario. Also sequential reads / writes only happen for large files if there is no fragmentation.