<![CDATA[Redump Forum — CD-R discs with C2 errors starting at LBA 321]]> 2026-03-14T21:53:59Z PunBB http://forum.redump.org/topic/70496/cdr-discs-with-c2-errors-starting-at-lba-321/ <![CDATA[Re: CD-R discs with C2 errors starting at LBA 321]]> LBA 319 appears to contain filesystem metadata:

000b72d0  00 ff ff ff ff ff ff ff  ff ff ff 00 00 06 19 02  |................|
000b72e0  00 00 00 00 00 00 00 00  05 01 03 00 03 00 00 00  |................|
000b72f0  9e dc 60 01 1f 00 00 00  00 00 00 00 04 00 00 00  |..`.............|
000b7300  01 00 00 f8 00 00 00 00  00 00 03 00 ff ff ff ff  |................|
000b7310  ff ff ff ff ef 3d 00 00  00 00 00 00 00 00 00 00  |.....=..........|
000b7320  c0 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000b7330  1c 12 e1 07 08 0b 03 01  33 18 08 00 1c 12 e1 07  |........3.......|
000b7340  08 0b 03 01 33 18 08 00  1c 12 e1 07 08 0b 03 01  |....3...........|
000b7350  33 18 08 00 01 00 00 00  00 00 00 00 00 00 00 00  |3...............|
000b7360  00 00 00 00 00 00 00 00  00 2a 4d 69 63 72 6f 73  |.........*Micros|
000b7370  6f 66 74 20 57 69 6e 64  6f 77 73 00 00 00 00 00  |oft Windows.....|
000b7380  06 00 00 00 00 00 00 00  10 00 00 00 00 00 00 00  |................|
000b7390  00 00 00 00 c0 00 00 00  b8 00 20 00 10 00 38 00  |.......... ...8.|
000b73a0  20 00 31 00 31 00 20 00  32 00 30 00 31 00 37 00  | .1.1. .2.0.1.7.|
000b73b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000b7410  00 00 00 00 00 00 00 00  00 00 00 13 ff ff ff ff  |................|
000b7420  00 00 00 00 01 00 00 00  01 02 01 02 01 02 00 00  |................|
000b7430  00 2a 4d 69 63 72 6f 73  6f 66 74 20 57 69 6e 64  |.*Microsoft Wind|
000b7440  6f 77 73 00 00 00 00 00  06 00 00 00 00 00 00 00  |ows.............|
000b7450  01 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000b7460  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
$ udfinfo /dev/sr0
udfinfo: Note: Found Virtual Allocation Table at block 26367 (expected at block 26370)
filename=/dev/sr0
label=8 11 2017
uuid=0301331620554446
lvid=8 11 2017
vid=UDF Volume
vsid= UDF Volume Set
fsid=UDF Volume Set
fullvsid=03013316 UDF Volume Set
owner=
organization=
contact=
appid=
impid=*Microsoft Windows
winserialnum=0x7c494ae4
blocksize=2048
blocks=26370
usedblocks=26080
freeblocks=333472
behindblocks=0
numfiles=1
numdirs=1
udfrev=2.01
udfwriterev=2.01
lastblock=26370
vatblock=26367
integrity=closed
accesstype=writeonce
softwriteprotect=no
hardwriteprotect=no
start=16, blocks=3, type=VRS
start=32, blocks=16, type=MVDS
start=64, blocks=16, type=RVDS
start=96, blocks=1, type=LVID
start=256, blocks=1, type=ANCHOR
start=288, blocks=359552, type=PSPACE
000b72d0  00 ff ff ff ff ff ff ff  ff ff ff 00 00 06 19 02  |................|
000b72e0  00 00 00 00 00 00 00 00  05 01 03 00 40 00 ac f7  |............@...|
000b72f0  e2 32 60 01 1f 00 00 00  00 00 00 00 04 00 00 00  |.2`.............|
000b7300  01 00 00 f8 00 00 00 00  00 00 03 00 ff ff ff ff  |................|
000b7310  ff ff ff ff ef 3d 00 00  00 00 00 00 00 00 00 00  |.....=..........|
000b7320  c0 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000b7330  00 10 dc 07 03 0d 06 13  00 2f 04 00 00 10 dc 07  |........./......|
000b7340  03 0d 06 13 00 2f 04 00  00 10 dc 07 03 0d 06 13  |...../..........|
000b7350  00 2f 04 00 01 00 00 00  00 00 00 00 00 00 00 00  |./..............|
000b7360  00 00 00 00 00 00 00 00  00 2a 4d 69 63 72 6f 73  |.........*Micros|
000b7370  6f 66 74 20 57 69 6e 64  6f 77 73 00 00 00 00 00  |oft Windows.....|
000b7380  06 00 00 00 00 00 00 00  10 00 00 00 00 00 00 00  |................|
000b7390  00 00 00 00 c0 00 00 00  b8 00 20 00 10 51 6b 53  |.......... ..QkS|
000b73a0  16 7b 2c 5f 10 8a 71 00  00 00 00 00 00 00 00 00  |.{,_..q.........|
000b73b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000b7410  00 00 00 00 00 00 00 00  00 00 00 0b ff ff ff ff  |................|
000b7420  00 00 00 00 01 00 00 00  01 02 01 02 01 02 00 00  |................|
000b7430  00 2a 4d 69 63 72 6f 73  6f 66 74 20 57 69 6e 64  |.*Microsoft Wind|
000b7440  6f 77 73 00 00 00 00 00  06 00 00 00 00 00 00 00  |ows.............|
000b7450  01 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000b7460  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
$ udfinfo /dev/sr0
udfinfo: Note: Found Virtual Allocation Table at block 64959 (expected at block 64962)
filename=/dev/sr0
label=八化第弐話
uuid=0613002c20554446
lvid=八化第弐話
vid=UDF Volume
vsid= UDF Volume Set
fsid=UDF Volume Set
fullvsid=0613002C UDF Volume Set
owner=
organization=
contact=
appid=
impid=*Microsoft Windows
winserialnum=0x2f072842
blocksize=2048
blocks=64962
usedblocks=64672
freeblocks=294624
behindblocks=0
numfiles=379
numdirs=26
udfrev=2.01
udfwriterev=2.01
lastblock=64962
vatblock=64959
integrity=closed
accesstype=writeonce
softwriteprotect=no
hardwriteprotect=no
start=16, blocks=3, type=VRS
start=20, blocks=16, type=MVDS
start=36, blocks=16, type=RVDS
start=52, blocks=1, type=LVID
start=256, blocks=1, type=ANCHOR
start=288, blocks=359296, type=PSPACE

The surrounding sectors are empty with invalid mode:
LBA 320 - mode E2
LBA 323 - mode 82
LBA 324 - mode 62
LBA 325 - mode 42
LBA 326 - mode 22

Then back to mode 2 and the start of actual data at LBA 327.

]]> http://forum.redump.org/user/8943/ 2026-03-14T21:53:59Z http://forum.redump.org/post/137333/#p137333 <![CDATA[Re: CD-R discs with C2 errors starting at LBA 321]]> My instinct is that it's something about how the UDF filesystem is being written to the CD-R, the 2 errors at LBA 321/322 might be the same cause as the end of the session, as if the first 322 sectors are written as one session, then the remainder as another?

Unfortunately I haven't added UDF parsing to sabretools yet like ISO9660, or else I'd get you to do a printout. Maybe you can spot something in the data around LBA 320 that seems common among the discs?

]]> http://forum.redump.org/user/63557/ 2026-03-13T03:27:40Z http://forum.redump.org/post/137258/#p137258 <![CDATA[CD-R discs with C2 errors starting at LBA 321]]> I've been dumping quite a few Japanese doujin games for IBM PC on CD-R media, and in addition to the common pattern of one erroneous sector at the end of the data track + one in lead-out, I have encountered several discs that all have a similar pattern of pairs of sectors with C2 errors, starting with LBA 321 and 322 and ending with the same pattern as other erroneous CD-Rs:

disc TOC:
  track 1 {  data, pre-emphasis }
    index 01 { LBA:      0, MSF: 00:02:00 }
  track A {  data, pre-emphasis }
    index 01 { LBA:   5826, MSF: 01:19:51 }

[LBA:    321] C2 error (bits: 1752)
[LBA:    322] C2 error (bits:   96)
[LBA:   5815] C2 error (bits: 1728)
[LBA:   5816] C2 error (bits:   96)
[LBA:   5825] C2 error (bits: 1704)
[LBA:   5826] C2 error (bits:  168)
disc TOC:
  track 1 {  data, pre-emphasis }
    index 01 { LBA:      0, MSF: 00:02:00 }
  track A {  data, pre-emphasis }
    index 01 { LBA: 311362, MSF: 69:13:37 }
[LBA:    321] C2 error (bits: 1560)
[LBA:    322] C2 error (bits:  480)
[LBA: 311332] C2 error (bits: 1560)
[LBA: 311333] C2 error (bits:  480)
[LBA: 311361] C2 error (bits: 1704)
[LBA: 311362] C2 error (bits:  504)
disc TOC:
  track 1 {  data, pre-emphasis }
    index 01 { LBA:      0, MSF: 00:02:00 }
  track A {  data, pre-emphasis }
    index 01 { LBA:  64962, MSF: 14:28:12 }

[LBA:    321] C2 error (bits: 1752)
[LBA:    322] C2 error (bits:  384)
[LBA:  64935] C2 error (bits: 1752)
[LBA:  64936] C2 error (bits:  384)
[LBA:  64961] C2 error (bits: 1656)
[LBA:  64962] C2 error (bits:  384)
disc TOC:
  track 1 {  data, pre-emphasis }
    index 01 { LBA:      0, MSF: 00:02:00 }
  track A {  data, pre-emphasis }
    index 01 { LBA:  26370, MSF: 05:53:45 }
[LBA:    321] C2 error (bits: 1776)
[LBA:    322] C2 error (bits:  120)
[LBA:  26288] C2 error (bits: 1680)
[LBA:  26289] C2 error (bits:  120)
[LBA:  26353] C2 error (bits: 1776)
[LBA:  26354] C2 error (bits:  120)
[LBA:  26369] C2 error (bits: 1776)
[LBA:  26370] C2 error (bits:  120)
disc TOC:
  track 1 {  data, pre-emphasis }
    index 01 { LBA:      0, MSF: 00:02:00 }
  track A {  data, pre-emphasis }
    index 01 { LBA:  53538, MSF: 11:55:63 }

[LBA:    321] C2 error (bits: 1776)
[LBA:    322] C2 error (bits:  624)
[LBA:  53517] C2 error (bits:  404)
[LBA:  53518] C2 error (bits: 2052)
[LBA:  53537] C2 error (bits: 1776)
[LBA:  53538] C2 error (bits:  120)

So far I have seen the pattern on 5 game discs from 3 different doujin groups. Given the regularity of the pattern, I think it has to be some kind of mastering issue rather than damage. The affected blocks are not used by any files, so I can easily copy the files off the disc in e.g. Windows Explorer. The games are playable from the copied files so it doesn't seem to be copy protection either. (I have never seen a doujin release with disc-based copy-protection.)

The affected discs seem to have other characteristics in common as well:

  • UDF filesystem

  • Mode 2

  • Pre-emphasis flag set

  • Other sectors with invalid mode adjoining the sectors with C2 errors

Has anyone else encountered this? I wonder if these discs can be considered eligible for Redump submission, for example using --force-split to replace the affected sectors with 0x55, if I can provide two sets of matching logs?

Example logs:
http://interbutt.com/misc/Aurorablast3_logs_Plextor.zip
http://interbutt.com/misc/Aurorablast3_ … iDrive.zip

]]> http://forum.redump.org/user/8943/ 2026-03-13T01:48:43Z http://forum.redump.org/post/137252/#p137252