Check flash cards integrity

gistfile1.txt

// SCRIPT

#!/bin/bash
dd if=/dev/urandom bs=1M count=1 of=somerandom
for i in $(seq 1 1000) 
do
    thisblock=$(shuf -i 0-63999 -n 1)
    sudo dd if=somerandom of=/dev/mmcblk0 bs=1M seek=$thisblock
    sudo sync
    sudo dd if=/dev/mmcblk0 skip=$thisblock bs=1M count=1 | diff - somerandom
    if [ $? == 1 ]
    then
        echo "bad"
        echo $thisblock >> badblocks
    else
        echo "good"
        echo $thisblock >> goodblocks
    fi
done


// CHECK RESULTS
$ wc -l goodblocks badblocks 
 240 goodblocks
 760 badblocks
1000 total


// PLOT RESULTS
goodblocks=dlmread("goodblocks");
badblocks=dlmread("badblocks");
image=zeros(320,200);
for i=goodblocks'
    x=floor(i/200)+1;
    y=(mod(i,200))+1;
    image(x,y)=1;
end
for i=badblocks'
    x=floor(i/200)+1;
    y=(mod(i,200))+1;
    image(x,y)=2;
end
colourmap=[0 0 0; 0 1 0; 1 0 0];
imshow(image+1,colourmap);
imwrite(image+1,colourmap,"image.png")