data DVD recovery on a "blank" disk?

onexused · 2020-05-10 03:37:55

Some years ago I did a data backup from an old computer onto a DVD+R DL (which my current DVD drive says it supports). When I inserted the disc earlier today and tried to mount it, mount hung and I got repeated tracebacks in dmesg and couldn't kill mount, suspend the computer, or reboot it normally. I didn't save the traceback before I synced the hard drive and pulled the plug.
Now, when I insert the disc, it reads as blank even though by looking at the back, I can see something was definitely burned on it. `ddrescue -d /dev/sr0 resuced.iso rescued.map` gives me a 0 byte file. `cdrecord -fix dev=/dev/sr0` (which has helped on discs burned with certain programs in the past) doesn't change this.

So: How can I read a DVD that's reported as blank but that I can tell by looking had data burned on it?

seth · 2020-05-10 06:18:20

You can't - the drive doesn't read the disc.
Do you have other DVD drives that you could try? In particular the one that burned the disc?

Rewritable disks were not very sturdy. After "some years" you stand almost no chance to read the data from it. And apparently you now also rewrote the TOC?? (What did "cdrecord -fix" respond?)

A forensic service w/ pro equipment *might* be able to recover parts of the data, but those services tend to be *very* expensive.

nl6720 · 2020-05-10 07:44:16

seth wrote:

Rewritable disks were not very sturdy.

DVD+R is not rewritable, DVD+RW is.

seth · 2020-05-10 08:07:24

Yeah, sorry. Readfilter.
(I only ever had DVD-R and DVD+RW. No -RW nor +R …)

The longevity of a DVD+R is typically better, but the problems are the same.
1. The TOC might be ruined now…
2. The readability varies w/ the drive (I have several DVD-R [sic!] that are reliably readable in the drive that burned them, "somewhat" in other drives (interestingly not after the first S3 but usually before) and not at all on others - this is not related to the age of the drive, though they're all old™ and all drives read pressed discs w/o any issue)

onexused · 2020-05-10 21:09:35

I actually don't know what cdrecord -fix does, just that it helped in some past cases, so maybe I did rewrite the TOC? It responded:

Cdrecord-ProDVD-ProBD-Clone 3.02a09 (x86_64-unknown-linux-gnu) Copyright (C) 1995-2016 Joerg Schilling
scsidev: '/dev/sr0'
devname: '/dev/sr0'
scsibus: -2 target: -2 lun: -2
Warning: Open by 'devname' is unintentional and not supported.
Linux sg driver version: 3.5.27
Using libscg version 'schily-0.9'.
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   : 
Vendor_info    : 'HL-DT-ST'
Identifikation : 'DVDRAM GT33N    '
Revision       : 'LT22'
Device seems to be: Generic mmc2 DVD-R/DVD-RW/DVD-RAM.
Using generic SCSI-3/mmc-3 DVD+R driver (mmc_dvdplusr).
Driver flags   : NO-CD DVD MMC-3 SWABAUDIO BURNFREE 
Supported modes: PACKET SAO LAYER_JUMP
cdrecord: Warning: Cannot read drive buffer.
cdrecord: Warning: The DMA speed test has been skipped.
Starting to write CD/DVD/BD at speed 6 in real TAO mode for single session.
Last chance to quit, starting real write    0 seconds. Operation starts.

I no longer have the drive which wrote the disc. In about a week I'll have access to another drive to check whether it can read the disc.

seth · 2020-05-10 21:22:03

idk what cdrinfo would do if a disk is falsely identified as blank/unformatted…
You could check

dvd+rw-mediainfo /dev/sr0
cdrecord -minfo  /dev/sr0
cdrecord -toc  /dev/sr0
cdrecord -atip  /dev/sr0

onexused · 2020-05-11 16:35:01

When I first tried these commands, the first one stopped responding and couldn't be killed. I found the following in dmesg: http://dpaste.com/0K5PF5E (Edit: I also saved the output of journalctl, but it looks like the same thing.)
After a reboot, the commands now return as follows:

% cdrecord -minfo /dev/sr0
cdrecord: No tracks allowed with '-minfo'.
Usage: cdrecord [options] track1...trackn

Use     cdrecord -help
to get a list of valid options.

Use     cdrecord blank=help
to get a list of valid blanking options.

Use     cdrecord dev=b,t,l driveropts=help -checkdrive
to get a list of drive specific options.

Use     cdrecord dev=help
to get a list of possible SCSI transport specifiers
% cdrecord -minfo
Cdrecord-ProDVD-ProBD-Clone 3.02a09 (x86_64-unknown-linux-gnu) Copyright (C) 1995-2016 Joerg Schilling
Linux sg driver version: 3.5.36
Using libscg version 'schily-0.9'.
No target specified, trying to find one...
Using dev=1,0,0.
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identifikation : 'DVDRAM GT33N    '
Revision       : 'LT22'
Device seems to be: Generic mmc2 DVD-R/DVD-RW/DVD-RAM.
Using generic SCSI-3/mmc-3 DVD+R driver (mmc_dvdplusr).
Driver flags   : NO-CD DVD MMC-3 SWABAUDIO BURNFREE
Supported modes: PACKET SAO LAYER_JUMP
cdrecord: Warning: Cannot read drive buffer.
cdrecord: Warning: The DMA speed test has been skipped.
Mounted media class:      DVD
Mounted media type:       DVD+R/DL
Disk Is not erasable
data type:                standard
disk status:              empty
session status:           empty
BG format status:         none
first track:              1
number of sessions:       1
first track in last sess: 1
last track in last sess:  1
Disk Is unrestricted
Disk type: DVD, HD-DVD or BD

Track  Sess Type   Start Addr End Addr   Size
==============================================
    1     1 Blank  0          4173823    4173824

Next writable address:              0
Remaining writable size:            4173824
% cdrecord -toc
Cdrecord-ProDVD-ProBD-Clone 3.02a09 (x86_64-unknown-linux-gnu) Copyright (C) 1995-2016 Joerg Schilling
Linux sg driver version: 3.5.36
Using libscg version 'schily-0.9'.
No target specified, trying to find one...
Using dev=1,0,0.
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identifikation : 'DVDRAM GT33N    '
Revision       : 'LT22'
Device seems to be: Generic mmc2 DVD-R/DVD-RW/DVD-RAM.
Using generic SCSI-3/mmc-3 DVD+R driver (mmc_dvdplusr).
Driver flags   : NO-CD DVD MMC-3 SWABAUDIO BURNFREE
Supported modes: PACKET SAO LAYER_JUMP
cdrecord: Warning: Cannot read drive buffer.
cdrecord: Warning: The DMA speed test has been skipped.
cdrecord: Input/output error. read toc: scsi sendcmd: no error
CDB:  43 00 00 00 00 00 00 00 04 00
status: 0x2 (CHECK CONDITION)
Sense Bytes: 70 00 05 00 00 00 00 0A 00 00 00 00 24 00 00 00
Sense Key: 0x5 Illegal Request, Segment 0
Sense Code: 0x24 Qual 0x00 (invalid field in cdb) Fru 0x0
Sense flags: Blk 0 (not valid)
cmd finished after 0.035s timeout 100s
cdrecord: Cannot read TOC header
cdrecord: Cannot read TOC/PMA.

% cdrecord -atip
Cdrecord-ProDVD-ProBD-Clone 3.02a09 (x86_64-unknown-linux-gnu) Copyright (C) 1995-2016 Joerg Schilling
Linux sg driver version: 3.5.36
Using libscg version 'schily-0.9'.
No target specified, trying to find one...
Using dev=1,0,0.
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identifikation : 'DVDRAM GT33N    '
Revision       : 'LT22'
Device seems to be: Generic mmc2 DVD-R/DVD-RW/DVD-RAM.
Using generic SCSI-3/mmc-3 DVD+R driver (mmc_dvdplusr).
Driver flags   : NO-CD DVD MMC-3 SWABAUDIO BURNFREE
Supported modes: PACKET SAO LAYER_JUMP
cdrecord: Warning: Cannot read drive buffer.
cdrecord: Warning: The DMA speed test has been skipped.
book type:       DVD+R/DL, Version (14.1)
disc size:       120mm (0)
maximum rate:    Not specified (15)
number of layers:2
track path:      Opposite Track Path (1)
layer type:      Rewritable Area (2)
linear density:  0.293 m/bit (1)
track density:   0.74 m/track (0)
phys start:      196608 (0x30000)
phys end:        16580607
end layer 0:     2283519
bca:             0
phys size:...    16384000
layer break at:  2086912
Category/Version        E1
Disk size               0F
Disk structure          32
Recoding density        10
Manufacturer:           'CMC MAG'
Media type:             'D03'
Product revision        64
ADIP numbytes           64
Reference speed         37
Max speed               37
L0 init status:  0
L0 data areacap: 2086912
Jump intervalsz: 0
Jump LBA:        4294770688
copyr prot type: 0
region mgt info: 0
cpm:             0
cgms:            0
rzone size:         36
rzone number:       1
border number:      1
ljrs:               0
track mode:         7 copy: 0
damage:             0
reserved track:     0 blank: 1 incremental: 1 fp: 0
data mode:          1
lra valid:          0
nwa valid:          1
rzone start:        0
next wr addr:       0
free blocks:        4173824
blocking factor:    16
rzone size:         4173824
last recorded addr: 0

    Capacity  Blklen/Sparesz.  Format-type  Type
     4173823             2048         0x00  Unformated or Blank Media
% dvd+rw-mediainfo /dev/sr0
INQUIRY:                [HL-DT-ST][DVDRAM GT33N    ][LT22]
GET [CURRENT] CONFIGURATION:
 Mounted Media:         2Bh, DVD+R Double Layer
 Media ID:              CMC MAG/D03
 Current Write Speed:   6.0x1385=8310KB/s
 Write Speed #0:        6.0x1385=8310KB/s
 Write Speed #1:        4.0x1385=5540KB/s
 Write Speed #2:        2.4x1385=3324KB/s
 Speed Descriptor#0:    00/4173823 R@6.0x1385=8310KB/s W@6.0x1385=8310KB/s
 Speed Descriptor#1:    00/4173823 R@6.0x1385=8310KB/s W@4.0x1385=5540KB/s
 Speed Descriptor#2:    00/4173823 R@6.0x1385=8310KB/s W@2.4x1385=3324KB/s
READ DVD STRUCTURE[#0h]:
 Media Book Type:       00h, DVD-ROM book [revision 0]
 Legacy lead-out at:    2086912*2KB=4273995776
DVD+R DOUBLE LAYER BOUNDARY INFORMATION:
 L0 Data Zone Capacity: 2086912*2KB, can still be set
READ DISC INFORMATION:
 Disc status:           blank
 Number of Sessions:    1
 State of Last Session: empty
 "Next" Track:          1
 Number of Tracks:      1
READ TRACK INFORMATION[#1]:
 Track State:           blank
 Track Start Address:   0*2KB
 Next Writable Address: 0*2KB
 Free Blocks:           4173824*2KB
 Track Size:            4173824*2KB
READ CAPACITY:          0*2048=0
%

Last edited by onexused (2020-05-11 16:36:36)

seth · 2020-05-11 20:20:56

The dmesg says that the system cannot read from the disk (the kernel module times out because most likely the drive doesn't answer because it's probably juggling around in a futile effort to focus on the disk)
Afterwards it considers the disk to be just blank because it cannot read the TOC (because it cannot read the disk, the behavior might depend on whether the disk is in the drive when the drive is initialized during the re/boot)

Arch Linux

#1 2020-05-10 03:37:55

data DVD recovery on a "blank" disk?

#2 2020-05-10 06:18:20

Re: data DVD recovery on a "blank" disk?

#3 2020-05-10 07:44:16

Re: data DVD recovery on a "blank" disk?

#4 2020-05-10 08:07:24

Re: data DVD recovery on a "blank" disk?

#5 2020-05-10 21:09:35

Re: data DVD recovery on a "blank" disk?

#6 2020-05-10 21:22:03

Re: data DVD recovery on a "blank" disk?

#7 2020-05-11 16:35:01

Re: data DVD recovery on a "blank" disk?

#8 2020-05-11 20:20:56

Re: data DVD recovery on a "blank" disk?

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