I'm using a couple DVD-Drives under Linux that show different default behaviour when it comes to faulty sectors.
Behaviour has been tested with a faulty commercial video DVD reading it sector wise (2048 bytes) with normal file seek and read functions.
One drive is a 'HL-DT-ST GHC0N'. This drive is the best in reading faulty sectors in my collection. It reports an error when it can't read a sector (often but not always the whole block produces errors then). The error profile for the DVD looks valid and shows the problematic range:
0.0%▁▕ ▁▃▆█▇▅▁▁ ▏▔28.9%
Another drive is a 'HL-DT-ST GH24NSD6'. This drive returns not a single read error for the whole DVD. Looking into the data reveals that it just returned zeroes for sectors it couldn't read.
I got the settings of the 'error recovery mode page' with sdparm --page 1 /dev/sr0 and both drives show the same values:
Read write error recovery mode page:
AWRE 1 [cha: y, def: 1]
ARRE 0 [cha: n, def: 0]
TB 0 [cha: n, def: 0]
RC 0 [cha: n, def: 0]
EER 0 [cha: n, def: 0]
PER 0 [cha: y, def: 0]
DTE 0 [cha: n, def: 0]
DCR 0 [cha: y, def: 0]
RRC 192 [cha: y, def:192]
COR_S 0 [cha: n, def: 0]
HOC 0 [cha: n, def: 0]
DSOC 0 [cha: n, def: 0]
EMCDR 0 [cha: n, def: 0]
WRC 0 [cha: n, def: 0]
ERWS 0 [cha: n, def: 0]
As they clearly show different behaviour there have to be additional settings regarding this, but where?
