sd card bad blocks

OpenSuse V13.2-64, KDE

I’m trying to copy files to a “bad” sd card and want to understand more about what is going on with the file system.

This is not a file recovery problem.

When diagnosing the problem, linux is more useful than windows XP because XP doesn’t even notice there’s a problem.

A long time ago I used floppy disks and under DOS would check its integrity with

 chkdsk a: /r /f  

When I perform a chkdsk on an sd card, no bad blocks are reported, but I know data is disappearing.

Can an sd card have a bad block marked?

What would cause Dolphin to lock up when accessing a bad sd card?

Thank you.

I did a

  dd if=/dev/zero of=/run/media/david/MIX/test1.txt  bs=1024

a few times ( 1,2,3,4,…) to fill the card, followed by a

 # dosfsck  -avt   /dev/sdc

fsck.fat 3.0.26 (2014-03-07)
fsck.fat 3.0.26 (2014-03-07)
Checking we can access the last sector of the filesystem
0x41: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
 Automatically removing dirty bit.
Boot sector contents:
System ID "MSDOS5.0"
Media byte 0xf8 (hard disk)
       512 bytes per logical sector
     16384 bytes per cluster
        34 reserved sectors
First FAT starts at byte 17408 (sector 34)
         2 FATs, 32 bit entries
   7828992 bytes per FAT (= 15291 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 15675392 (sector 30616)
   1957187 data clusters (32066551808 bytes)
63 sectors/track, 255 heads
         0 hidden sectors
  62660608 sectors total
Checking for bad clusters.
Reclaiming unconnected clusters.
Checking free cluster summary.
Performing changes.
/dev/sdc: 9 files, 1957187/1957187 clusters

followed by a

 badblocks /dev/sdc 

which returned nothing.