[kwlug-disc] udisksd slow to mount USB stick

[Bob Jonkman]

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In one of the CCC presentations I heard a few years ago, Bunny Huang
said that the memory in SD cards and thumb drives were notoriously
unreliable, every device requiring an on-board processor to maintain
data accuracy by error correction. He told of "large" 2 GByte chips
failing 3/4 of their memory tests, and so being reconfigured as 512
MByte chips.  But this statement made me worry. Bunny said "these
chips don't store your data, they store a statistical approximation of
your data."

Perhaps your drive is reaching its end-of-life. If that tiny onboard
processor has to recreate your data from statistical approximations
every time you insert it in your computer, perhaps it's time to get a
new one.

- --Bob.

The Exploration and Exploitation of an SD Memory Card [30c3]:
 https://www.youtube.com/watch?v=Tj-zI8Tl218


Bob Jonkman <bjonkman at sobac.com>          Phone: +1-519-635-9413
SOBAC Microcomputer Services             http://sobac.com/sobac/
Software   ---   Office & Business Automation   ---   Consulting
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On 2016-03-24 06:00 PM, Khalid Baheyeldin wrote:
> On Thu, Mar 24, 2016 at 12:27 PM, William Park
> <opengeometry at yahoo.ca> wrote:
>> 
>> 1. badblocks -b4096 -swv /dev/sdb
> 
> # badblocks -b4096 -swv /dev/sdb Checking for bad blocks in
> read-write mode From block 0 to 250622 Testing with pattern 0xaa:
> done Reading and comparing: done Testing with pattern 0x55: done 
> Reading and comparing: done Testing with pattern 0xff: done Reading
> and comparing: done Testing with pattern 0x00: done Reading and
> comparing: done Pass completed, 0 bad blocks found. (0/0/0 errors)
> 
>> 2. dd if=/dev/zero of=/dev/sdb bs=1M oflag=direct
> 
> # dd if=/dev/zero of=/dev/sdb bs=1M oflag=direct dd: error writing
> ‘/dev/sdb’: No space left on device 979+0 records in 978+0 records
> out 1026555392 bytes (1.0 GB) copied, 185.655 s, 5.5 MB/s
> 
> So no media errors in both commands.
> 
> I used fdisk to create a partition, and created a vfat filesystem.
> 
> Same lag. Took 1 minute 20 seconds from sdb1 being recognized, to 
> udisksd mounting it.
> 
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