I have DVD drive Sony DRU-700A. It worked normally something about 10 month.
But few day ago strange bug apperead. When I read files from DVD+RW disk which was burned not on my drive all data from disk was successfuly copied to hard drive. But when I try to read files from this disc second time after about a hour 2 files can't be read due to crc errors. When I try to read it next day a lot of new "badblocks" apperead on this disk.
So I decided to do a small test. I've burned 4 disks: two Samsung Pleomax DVD+RW, Pleomax DVD-RW and Esperanza DVD+RW. After burning all data from disk was read normally without any errors. Kprobe graphics for this disks also was normal. But when I try to read this disks next day there was crc errors on 3 disks of 4. Only one Pleomax DVD+RW hadn't errors. There was no any sratches and mechanical damages on disks.
And disks have the same errors on the same sectors when I try to read its on other DVD drive.
Firmware upgrade from VY06 to VY08 didn't help.
Looks like my DVD drive broken someway, but how can it corrupt data on +/-RW disks while reading?