A note on creating microSD from img file ... on performance

Discussion in 'UDOO NEO' started by sieler, Nov 15, 2015.

  1. sieler

    sieler New Member

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    Hi,

    The process of creating the microSD card requires copying the .img file to the card ... which involves
    writing about 2.9 GB.

    But ... not all method of connecting a microSD card to your computer are equal.

    On my Mac, I noticed that one "card reader" was letting me write about 1 MB/sec (one megabyte per second),
    but another (a double-ended device from Unirex (one end USB A male (aka plug), the other end
    micro USB male, with a slot for SD and a slot for microSD)) let me write at about 6 MB/sec!

    In other words, not all methods of writing to SD or microSD cards are created alike! If you have more than
    one device, time them!

    On my late 2008 Mac Pro laptop, with the faster device, it takes 8 minutes and 45 seconds to write the .img file to the microSD.
     
  2. madxray

    madxray New Member

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    you can also monitor the copy status with tools like pv or
    pkill -usr1 dd (linux only)
    This helped me to stay patient ;)
     
  3. sieler

    sieler New Member

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    Good point, madxray ...

    I should have mentioned: I have my own version of 'dd' (called 'ddcopy') which reports progress as it goes. Example output:
    ...
    2:05:31 #records = 11 read 44 MB; 44.00 MBs/sec; 6% done; 15 seconds left
    ...
    (the above is not an example from writing to a microSD card, as you can tell by the speed :)

    It's a command-line program. If anyone wants a copy (Linux or Mac, for free), drop me a line.
    sieler at allegro.com

    Stan
     

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