USB copy problem.

[Aristotelis]

On 06/23/2010 09:01 PM, J wrote:
> On Wed, Jun 23, 2010 at 11:33, Aristotelis<agliak at gmail.com>  wrote:
>    
>> Hello, i am using ubuntu 10.04 x86_64. I'm having a certain problem
>> while copying from my internal HDD (ext4) to usb stick (fat32). At first
>> I get a good speed for the first half of the file (approx. 1.5 GB) and
>> then it slows down but not significantly or in an annoying way...
>> The actual problem and my question is that when file transfer window
>> informs me that 1.5GB/1.5GB have been transfered and 0 seconds remain,
>> the window remains there for about 30 seconds. I also realized that when
>> copying multiple files, copying is stalled after each file being copied.
>> System is fully functional during this time but it seems to me that a
>> task is being done that won't let me safely remove my usb stick when i
>> try to.
>> Any help or information would be appreciated! Thanks in advance!
>>      
> Most likely normal... you are transferring a 1.5GB file, after all...
>
> when you copy or move a file onto that USB disk, you aren't writing
> directly to the disk, you're writing to a buffer that then gets
> written to disk, so in reality, most of the time, when that transfer
> window says 1.5 of 1.5 copied and 0 seconds remaining, the hardware is
> STILL writing the file to the USB device, even though the software has
> finished what it was doing.
>
> The amount of time this can take varies on many things, including the
> write speed of the USB stick, the speed of the port (USB1.1 v USB
> 2.0), how much stuff is running on your system (writing files uses up
> some processor time) the amount of other things going on on the USB
> bus, etc...
>
> So yeah, for a 1.5GB file, that sounds about right.
>
>    
Thanks for your interest and answer but i still believe something is 
wrong, because i've been using the same usb device (usb 2.0 by the way) 
to other ubuntu distros and generally other OS in the same system but 
never had the same issue...Of course you're right about the large size 
of the file being copied but I encounter same behavior to smaller 
transfers (~100 MB). A little detail that I missed to mention is that 
while copying several files, after the transfer of each one it seems 
there is a pause, for example copy two files 100 MB each, so 200MB max, 
I get the first 100MB transfered normally (as the window informs me) 
then a pause like nothing is going on and then continue to the rest. At 
the time of the copy there isn't any other task consuming CPU power. At 
first I thought it was something like the OS was verifying copied data 
but I don't know for sure.
Excuse me if I insist too much and I hope I don't become annoying but it 
seems weird to me!
Again thanks for your help!