Back to 2011, I bought a couple of usb-sticks from Amazon, TDK and Sandisk brand new sticks, supposed to be "decent quality" for a kind of backup kind of backup you carefully store inside a locker and don't touch for years.
Yesterday night I mounted those usb-sticks in my Linux box to read some old files and ...
sd 7:0:0:0: [sdc] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 7:0:0:0: [sdc] tag#0 Sense Key : Medium Error [current]
sd 7:0:0:0: [sdc] tag#0 Add. Sense: Unrecovered read error
sd 7:0:0:0: [sdc] tag#0 CDB: Read(10) 28 00 00 1c 42 1e 00 00 f0 00
blk_update_request: critical medium error, dev sdc, sector 1851934
sd 7:0:0:0: [sdc] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 7:0:0:0: [sdc] tag#0 Sense Key : Medium Error [current]
sd 7:0:0:0: [sdc] tag#0 Add. Sense: Unrecovered read error
sd 7:0:0:0: [sdc] tag#0 CDB: Read(10) 28 00 00 1c 42 a8 00 00 02 00
blk_update_request: critical medium error, dev sdc, sector 1852072
Buffer I/O error on dev sdc1, logical block 926005, async page read
sdc: sdc1 sdc2 sdc3
sd 7:0:0:0: [sdc] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 7:0:0:0: [sdc] tag#0 Sense Key : Medium Error [current]
sd 7:0:0:0: [sdc] tag#0 Add. Sense: Unrecovered read error
sd 7:0:0:0: [sdc] tag#0 CDB: Read(10) 28 00 00 7a e0 60 00 00 f0 00
blk_update_request: critical medium error, dev sdc, sector 8052832
sd 7:0:0:0: [sdc] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 7:0:0:0: [sdc] tag#0 Sense Key : Medium Error [current]
sd 7:0:0:0: [sdc] tag#0 Add. Sense: Unrecovered read error
sd 7:0:0:0: [sdc] tag#0 CDB: Read(10) 28 00 00 7a e1 60 00 00 f0 00
blk_update_request: critical medium error, dev sdc, sector 8053088
sd 7:0:0:0: [sdc] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 7:0:0:0: [sdc] tag#0 Sense Key : Medium Error [current]
sd 7:0:0:0: [sdc] tag#0 Add. Sense: Unrecovered read error
sd 7:0:0:0: [sdc] tag#0 CDB: Read(10) 28 00 00 7a e1 00 00 00 08 00
blk_update_request: critical medium error, dev sdc, sector 8052992
Buffer I/O error on dev sdc3, logical block 394064, async page read
Quick test
dd of=/dev/null if=/dev/sdc3
dd: reading '/dev/sdc3': Input/output error
3152512+0 records in
3152512+0 records out
1614086144 bytes (1.6 GB) copied, 1521.2 s, 1.1 MB/s
Thanks god, I also saved all those files in DVD-ram cartridges and even a copy on an hard-disk, which are all in perfect working condition.
Not a single file was lost.
Moral of the story: don't trust USB-sticks!