Should it take 50 minutes to copy 1.5GB to a USB2 memory stick?

Discussion in 'NZ Computing' started by Mark C, Mar 19, 2008.

  1. Mark C

    Mark C Guest

    Should it take 50 minutes to copy 1.5GB to a USB2 memory stick?

    The DSE site says the stick is USB2.0.
    My USB external HDD can read @ ~28Mbyte/s thru the same USB ports.

    The file copy starts off with a ~4min estimate, and then blows out to
    50min, oscillating about.

    Performance monitor showed a steady baseline write speed of
    200KBytes/s, peaking to 800KBytes/s sometimes and 6MBytes/s rarely.
    A disk test utility showed it can be read from @ 12MBytes/s.

    Windows 2000 Server SP4, patched.

    Oh well...

    Mark C, Mar 19, 2008
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  2. Mark C

    impossible Guest

    Are you transferring many, many files? And is your USB drive formatted Fat16
    by any chance? If so, that could be the source of your trouble.
    impossible, Mar 20, 2008
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  3. Mark C

    Craig Shore Guest

    Try a different USB port on the machine.
    Craig Shore, Mar 20, 2008
  4. Mark C

    RL Guest

    Large numbers of files alone will also dramatically slow file copying to
    flash memory, although it may depend on how you have it configured. I
    have mine configured for performance over reliability.

    Flash memory is inefficient at wriging, so having to constantly update
    file tables with large numbers of entries will be much slower than
    copying a single file. If I need to pur a large number of files on flash
    memory, I will usually zip them up first, and it is much faster that way.

    RL, Mar 20, 2008
  5. I don't see why. I've had directories with hundreds of thousands of files in
    them, which could be copied around just fine between rotating media, across
    the LAN etc. Why should flash be any worse at dealing with this?
    How do you do that, then?
    Lawrence D'Oliveiro, Mar 20, 2008
  6. Mark C

    RL Guest

    This is because of the way flash memory works. Memory is arranged in
    blocks, of which wach bit has a natural value of 1. The state of the bit
    can be individually changed from 1 to 0, but not 0 to 1. Therefore, to
    write a small block of data as is required for a file table entry, the
    entire block must be erased and re-written.
    On Windows, this is set in the device properties. In Vista, this is
    accessible via Explorer, right click on a drive and select Properties.
    Select the Hardware tab, then the flash device from the "All disk
    drives" list. Select 'Properties', then the 'Policies' tab. You get two
    options "Optimize for quick removal" and "Optimize for performance".

    RL, Mar 20, 2008
  7. What do you mean by "file table entry"? Do you mean "inode"? And what
    difference does it make how big or small they are, when you can just write
    a bunch of them at once?
    Sounds like a long-winded way of setting the "cache size".
    Lawrence D'Oliveiro, Mar 20, 2008
  8. Mark C

    J Brockley Guest

    This is just setting write behind caching. Turned on you get windows back
    quicker and writing continues in the background. This may lead you to
    believe save is complete and pull out stick. Disabled, means saving data
    ties up the app until finished. Doesn't stop you pulling it out early but at
    least you have a indication that data is still saving.
    J Brockley, Mar 21, 2008
  9. Mark C

    Craig Shore Guest

    So if you've got it optimised for performance then you'd have to make
    sure you always stop the device so it's safe to remove?
    Craig Shore, Mar 21, 2008
  10. That would be exactly right. "Performance" means "caching", and "caching"
    means "risk of data loss if caches are not properly flushed".
    Lawrence D'Oliveiro, Mar 21, 2008
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