/path/to/your/hdparm -t --direct /dev/mmcblk1
# /home/nemo/horst-NFS/hdparm-9.48/hdparm -t --direct /dev/mmcblk1 /dev/mmcblk1: Timing O_DIRECT disk reads: 62 MB in 3.04 seconds = 20.40 MB/sec
# /home/nemo/horst-NFS/hdparm-9.48/hdparm -t --direct /dev/mmcblk0 /dev/mmcblk0: Timing O_DIRECT disk reads: 210 MB in 3.02 seconds = 69.57 MB/sec…