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
