Notices

Not sure if it's the same since I don't have an a 32gb class 10 card, but have you checked out the Fix for Class 10 microSD cards thread?

is not an issue of the card is to use "/ dev / null"

To write and read it I had no problems.

what are you doing with /dev/null anyways? messuring the speed of /dev/null/ ?

further: no problems reading from /dev/null ? you didn't ("Reads from /dev/null shall always return end-of-file ")! so what did you do?

3 Consecutive runs of 100MB test script.
Lenco 16GB class 6

Nokia-N900:/home/user# ./testsd.sh
testing SD Card read/write speed. Please wait a few minutes.
Testing _WRITE SPEED
Testing READ SPEED
Deleting test file
Result
Read: 10.2354 MB/s
Write: 12.4069 MB/s

Nokia-N900:/home/user# ./testsd.sh
testing SD Card read/write speed. Please wait a few minutes.
Testing _WRITE SPEED
Testing READ SPEED
Deleting test file
Result
Read: 6.77507 MB/s
Write: 20.7469 MB/s

Nokia-N900:/home/user# ./testsd.sh
testing SD Card read/write speed. Please wait a few minutes.
Testing _WRITE SPEED
Testing READ SPEED
Deleting test file
Result
Read: 7.08215 MB/s
Write: 21.978 MB/s



EDIT: New Test with 1GB test file
testing SD Card read/write speed. Please wait a few minutes.
Testing WRITE SPEED
Testing READ SPEED
Deleting test file
Result
Read: 12.221 MB/s
Write: 3.12109 MB/s



Conclusion:Unconclusive

The line of script that checks from the card reading done:

"time -p cp / media/mmc1/test.dat /dev/null"

The virtual device "/dev/null" is a black hole. Where not to save anything, is used to simulate the copy from one point to another point.

In my device returns the following message:

"cp: can create ' dev/null ' : File exists"

in my GNU/Linux the script works perfectly.

I have tried to re-create "/ dev / null".

# Sudo gainroot

# Mv / dev / null / dev / null.old
# Mknod-m 0666 / dev / null c 1 3

The result is that in writing ...

# Ls -l /dev/null

It shows that ceased to occupy 9MB, but still displays the same error messages when using "/dev/null"

Fixed. It allows the use of "/dev/null" as the destination for the command "cp".

I've solved it using "dd" to replace cpmando "cp".

I put the example:

dd if=$DAT of=/dev/null bs=1M 2>&1|head -1