$ head /sys/block/mmcblk0/device/* ==> /sys/block/mmcblk0/device/cid <== 1b534d303030303010771d8e8000c900 ==> /sys/block/mmcblk0/device/csd <== 400e00325b590000e9e57f800a404000 ==> /sys/block/mmcblk0/device/date <== 09/2012 ==> /sys/block/mmcblk0/device/erase_size <== 512 ==> /sys/block/mmcblk0/device/fwrev <== 0x0 ==> /sys/block/mmcblk0/device/hwrev <== 0x1 ==> /sys/block/mmcblk0/device/manfid <== 0x00001b ==> /sys/block/mmcblk0/device/name <== 00000 ==> /sys/block/mmcblk0/device/oemid <== 0x534d ==> /sys/block/mmcblk0/device/preferred_erase_size <== 4194304 ==> /sys/block/mmcblk0/device/scr <== 02b5800200000000 ==> /sys/block/mmcblk0/device/serial <== 0x771d8e80 ==> /sys/block/mmcblk0/device/type <== SD ==> /sys/block/mmcblk0/device/uevent <== DRIVER=mmcblk MMC_TYPE=SD MMC_NAME=00000 MODALIAS=mmc:block
$ sudo fdisk -lu /dev/mmcblk0 Disk /dev/mmcblk0: 31.4 GB, 31393316864 bytes 255 heads, 63 sectors/track, 3816 cylinders, total 61315072 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
Device Boot Start End Blocks Id System /dev/mmcblk0p1 8192 61315071 30653440 c W95 FAT32 (LBA)
$ sudo hexdump -C /dev/mmcblk0 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 82 |................| 000001c0 03 00 0c fe ff ff 00 20 00 00 00 78 a7 03 00 00 |....... ...x....| 000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00400000 eb 00 90 20 20 20 20 20 20 20 20 00 02 40 8c 05 |... ..@..| 00400010 02 00 00 00 00 f8 00 00 3f 00 ff 00 00 20 00 00 |........?.... ..| 00400020 00 78 a7 03 3a 1d 00 00 00 00 00 00 02 00 00 00 |.x..:...........| 00400030 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00400040 80 00 29 f8 4e 16 90 4e 4f 20 4e 41 4d 45 20 20 |..).N..NO NAME | 00400050 20 20 46 41 54 33 32 20 20 20 00 00 00 00 00 00 | FAT32 ......| 00400060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 004001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00400200 52 52 61 41 00 00 00 00 00 00 00 00 00 00 00 00 |RRaA............| 00400210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 004003e0 00 00 00 00 72 72 41 61 ff ff ff ff 02 00 00 00 |....rrAa........| 004003f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00400400 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 004005f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00400600 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00400c00 eb 00 90 20 20 20 20 20 20 20 20 00 02 40 8c 05 |... ..@..| 00400c10 02 00 00 00 00 f8 00 00 3f 00 ff 00 00 20 00 00 |........?.... ..| 00400c20 00 78 a7 03 3a 1d 00 00 00 00 00 00 02 00 00 00 |.x..:...........| 00400c30 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00400c40 80 00 29 f8 4e 16 90 4e 4f 20 4e 41 4d 45 20 20 |..).N..NO NAME | 00400c50 20 20 46 41 54 33 32 20 20 20 00 00 00 00 00 00 | FAT32 ......| 00400c60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00400df0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00400e00 52 52 61 41 00 00 00 00 00 00 00 00 00 00 00 00 |RRaA............| 00400e10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00400fe0 00 00 00 00 72 72 41 61 ff ff ff ff 02 00 00 00 |....rrAa........| 00400ff0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00401000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 004011f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00401200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 004b1800 f8 ff ff 0f ff ff ff 0f ff ff ff 0f 00 00 00 00 |................| 004b1810 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00858c00 f8 ff ff 0f ff ff ff 0f ff ff ff 0f 00 00 00 00 |................| 00858c10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00c08000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| *
$ sudo ./flashbench --open-au --open-au-nr=31 --erasesize=$[512 * 1024] --blocksize=1024 /dev/mmcblk0 --offset=$[24*1024*1024] 512KiB 5.5M/s 256KiB 8.3M/s 128KiB 7.71M/s 64KiB 7.08M/s 32KiB 5.08M/s 16KiB 2.92M/s 8KiB 1.29M/s 4KiB 660K/s 2KiB 344K/s 1KiB 173K/s arnd@klappe2:~/git/flashbench$ sudo ./flashbench --open-au --open-au-nr=30 --erasesize=$[512 * 1024] --blocksize=1024 /dev/mmcblk0 --offset=$[24*1024*1024] 512KiB 9.2M/s 256KiB 8.42M/s 128KiB 8.4M/s 64KiB 9.05M/s 32KiB 7.38M/s 16KiB 4.67M/s 8KiB 3.68M/s 4KiB 2.58M/s 2KiB 1.52M/s 1KiB 874K/s
$ sudo ./flashbench --open-au --open-au-nr=30 --erasesize=$[512 * 1024] --blocksize=1024 /dev/mmcblk0 --offset=$[24*1024*1024] --random 512KiB 8.78M/s 256KiB 7.82M/s 128KiB 8.93M/s 64KiB 8.68M/s 32KiB 6.95M/s 16KiB 4.85M/s 8KiB 2.41M/s 4KiB 1.3M/s 2KiB 649K/s