Re: DVD-Ram diagnostics
Greetings,
on saturday april 17th 2004 12:12 Andy Polyakov wrote:
> >>>I was told, that DVD-Ram is very secure because of its structure. Today
> >>> a nearly four months old DVD-Ram failed. (Maxell, non-cartrigde
> >>> version). My LG-4081B throw some i/o errors when I tried to dd the
> >>> dvd-ram with random data in order to encrypt it.
> >>>I could not see any scratches, dust or any fingerprints on the dvd.
> >>>What might have gone wrong? How can I detect it? How do I proctect my
> >>>other backups?
> But back to the problem. You've got to elaborate on "some i/o errors."
Ok:
Apr 14 13:00:34 donald kernel: end_request: I/O error, dev 16:00 (hdc), sector
12028
Apr 14 13:00:34 donald kernel: end_request: I/O error, dev 16:00 (hdc), sector
12030
etc.
> > Is it a media-error or do I do have to upgrade firmware or are there any
> > known linux-kernel issues?
>
> Quoting specification:
>
> "The DVD-RAM format is designed to enable the following Linear
> Replacement methods, with some consideration for issues of real-time
> data recording, where for example the reassignments are disabled during
> some operations.
>
> - When recording data with verification by the WRITE AND VERIFY (10)
> command, the logical unit has an opportunity to evaluate the written
> data and if the data is found defective, the logical unit may perform a
> Linear Replacement.
>
> - For data recorded without verification, the logical unit has an
> opportunity to evaluate the written data when the host attempts to read
> the data from that LBA and if the data is found defective but
> correctable by ECC, the logical unit may perform the Linear Replacement
> operation, if read reassignment is enabled."
>
> As you read the quote you ask yourself following questions.
>
> - Was data recorded in "real-time mode, where reassignments are
> disabled?" No. "Real-time recording" implies that writes are performed
> with WRITE(12) command with "Streaming" bit set. Linux kernel never uses
> it. - But was data recorded "with verification by the WRITE AND VERIFY (10)
> command?" No. Linux kernel doesn't use WRITE AND VERYFY command when
> writing DVD-RAM.
Can I patch linux for doing so or which (unix-like) os do you recommend for
doing so?
> - But is "read reassignment enabled?" I don't know. How to tell? There
> is an ARRE, Automatic Read Reallocation Enable bit in page 01. You can
> dump the pages with 'dvd+rw-mediainfo /dev/dvd verbose'. Send the output
> to the list, so we can see if ARRE is on.
Ok, appended . (Note: there is no meaningful data on the dvd. I did dd
if=/dev/urandom of=/dev/hdc in order to prepare the dvd for crypto-data.)
> However! Even if ARRE is on,
Puhh... I don't see any entry indicating whether it is or it is not.
> there is yet another possibility for things
> to *appear* broken. Specfication mentions that unit raises a warning
> condition when Supplementary Spare Aread is about to be exhausted and
> needs to be grown. If Linux kernel does not interpret it as warning (at
> the very least it could ignore it and log a message at console), it
> shall appear as I/O error to application. As for growing spare area.
> Note that it implies that filesystem can be shrunk. As it's problematic
> to shrink file systems, it might actually make sense to maximize the
> spare area prior creating file system. Note that I don't know if
> there're Linux apps readily available that will let you grow spare area
> or manipulate ARRE bit. The above suggestions has rather theoretical
> character as they are not based on personal experience (don't have
> DVD-RAM capable unit).
Puh... sounds bad. What do you recommend to get safe backups? (No - Windows is
not an option ;)
> Bottom line. "some I/O erors" is not good enough to tell what's going
> on. Examine kernel log to find out the exact error code. A.
see above.
Thanks for your help.
Keep smiling
yanosz
dvd+rw-mediainfo /dev/hdc verbose
INQUIRY: [HL-DT-ST][DVDRAM GSA-4081B][A100]
MODE SENSE[#3Fh]:
01: 80 13 00 00 00 00 03 00 00 00
05: 60 05 08 10 00 00 00 00 00 00 00 20 00 96 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00
88: 04 00 08 00 00 00 00 80 00 80
8D: 00 0b 00 3c 00 4b
0E: 04 00 00 00 00 4b 01 ff 02 ff 00 00 00 00
18: 00 01 00 01 00 00 00 01 00 01 00 01 00 00 00 01
00 01 00 01 00 01 00 01 00 00
9A: 00 03 00 00 04 b0 00 00 09 60
9C: 00 04 00 00 02 58 00 00 00 00
9D: 00 00 00 00 00 1e 2a 30
A0: 01 00 00 64 00 03 00 00 00 00
2A: 3f 37 f1 73 29 23 10 3b 01 00 08 00 10 3b 00 00
10 3b 10 3b 00 01 00 00 00 00 10 3b 00 01 00 00
10 3b 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00
MODE SENSE[#2A]:
2A: 3f 37 f1 73 29 23 10 3b 01 00 08 00 10 3b 00 00
10 3b 10 3b 00 01 00 00 00 00 10 3b 00 01 00 00
10 3b 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00
GET [CURRENT] CONFIGURATION:
0000: 00 12 01 00 00 11 00 00 00 14 00 00 00 13 00 00
00 1a 00 00 00 1b 00 00 00 10 00 00 00 09 00 00
00 0a 00 00 00 08 00 00 00 02 01 00
0001: 00 00 00 02
0002: 00 00 00 00
0003: 29 00 00 00
0004: 02 00 00 00
0010: 00 00 08 00 00 10 01 00
001F:
0020: 00 22 21 1f 00 00 08 00 00 10 01 00
0023:
0024: 80 00 00 00
0037: 00 07 00 00
0100:
0101: 01 00 00 00
0105:
0107: 1f 00 00 00
0108: 4b 31 45 33 43 32 42 34 30 35 35 20
010B: 00 00 00 01
010C: 32 30 30 33 31 31 32 38 31 32 33 34 35 36 00 00
Mounted Media: 12h, DVD-RAM
:-[ READ DVD STRUCTURE#11 failed with SK=5h/ASC=24h/ACQ=00h]: Input/output
error
Current Write Speed: 3.0x1385=4155KB/s
Write Speed #0: 3.0x1385=4155KB/s
GET CURRENT PERFORMANCE: 02 00 00 00 00 00 00 00 00 00 10 3b 00 22 21
1f 00 00 10 3b
Write Performance: 3.0x1385=4155KB/s@[0 -> 2236703]
GET PERFORMANCE: 02 00 00 00 00 22 21 1f 00 00 10 3b 00 00 10 3b
Speed Descriptor#0: 02/2236703 R@3.0x1385=4155KB/s W@3.0x1385=4155KB/s
READ DVD STRUCTURE[#FF]:
STRUCTURE#00 40:2052
STRUCTURE#01 40:8
STRUCTURE#02 40:2052
STRUCTURE#03 40:192
STRUCTURE#04 c0:2052
STRUCTURE#05 40:8
STRUCTURE#06 40:24
STRUCTURE#07 40:24580
STRUCTURE#08 40:2052
STRUCTURE#09 40:8
STRUCTURE#0a 40:16
STRUCTURE#0b 40:8
STRUCTURE#c0 c0:8
READ DVD STRUCTURE[#0h]: 16 0f 04 42 00 03 10 00 00 26 5f 5f 00 00 00
00
Media Book Type: 16h, DVD-RAM book [revision 6]
Legacy lead-out at: 2314080*2KB=4739235840
READ DISC INFORMATION: 00 20 1f 01 01 01 01 00 ff 00 00 00 00 00 00 00
Disc status: other
Number of Sessions: 1
State of Last Session: complete
"Next" Track: 1
Number of Tracks: 1
READ FORMAT CAPACITIES:
formatted: 2236704*2048=4580769792
00h(800): 2236704*2048=4580769792
00h(800): 2295072*2048=4700307456
01h(800): 2226976*2048=4560846848
01h(800): 2217248*2048=4540923904
READ TRACK INFORMATION[#1]: 00 22 01 01 00 04 01 00 00 00 00 00 00 00 00
00
Track State: complete
Track Start Address: 0*2KB
Free Blocks: 0*2KB
Track Size: 2236704*2KB
FABRICATED TOC: 18 1 1
Track#1 : 14@0
Track#AA : 14@2236704
Multi-session Info: #1@0
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