Testing SD cards (and other memory)
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I have installed (compiled in a chroot'ed system on my BQ E4.5) a small tool
f3writewhich tests a SD by writing a random byte pattern into files of 1 GByte size and a checksum for each file into it. Its counterpartf3readcan be used to read the files again and see if their contents match the checksums. See below. The source for the tool can be fetched from here: https://codeload.github.com/AltraMayor/f3/tar.gz/v6.0?dummy=/AltraMayor-f3-v6.0_GH0.tar.gzThis tool helps as well against companies selling write only USB sticks or other memory, "1 TByte for 10 Euro", but you can only write (without any error) and never read back your important files.
# bin/f3write /media/phablet/9CC0-D6CE Free space: 15.42 GB Creating file 1.h2w ... OK! Creating file 2.h2w ... OK! Creating file 3.h2w ... OK! ... Free space: 0.00 Byte Average writing speed: 12.35 MB/s # ls -l /media/phablet/9CC0-D6CE total 16170552 -rw-r--r-- 1 phablet phablet 1073741824 Apr 24 13:14 10.h2w -rw-r--r-- 1 phablet phablet 1073741824 Apr 24 13:16 11.h2w -rw-r--r-- 1 phablet phablet 1073741824 Apr 24 13:17 12.h2w -rw-r--r-- 1 phablet phablet 1073741824 Apr 24 13:19 13.h2w -rw-r--r-- 1 phablet phablet 1073741824 Apr 24 13:20 14.h2w -rw-r--r-- 1 phablet phablet 1073741824 Apr 24 13:21 15.h2w ... # bin/f3read /media/phablet/9CC0-D6CE SECTORS ok/corrupted/changed/overwritten Validating file 1.h2w ... 2097152/ 0/ 0/ 0 Validating file 2.h2w ... 2097152/ 0/ 0/ 0 Validating file 3.h2w ... 8259/ 0/ 0/ 0 ...