A bit of investigation and the sacrifice of one blank CD for the greater ubuntu good later, it looks a lot like the errors are being caused by the default burn mode: cdrecord defaults to SAO mode: Works. wodim defaults to TAO mode: Fails. wodim forced to use SAO mode: Works. The behaviour is described here: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=427771 http://lists.alioth.debian.org/pipermail/debburn-devel/2009-July/000661.html Looks like the consensus is that it just happens with TAO mode and these disks have some bad blocks at the end, so they should be padded (are the ubuntu isos?!) and we have to live with it. I'd rather be able to copy the image back to hd and do an md5 of the drive, however. Further logs attached to show the modes (I leave out the probable fail case of cdrecord running in TAO): Wodim, by default, seems to run in TAO mode and fails ----------------------------------------------------- rich@neon:~/Source/cdrtools-2.01.01$ wodim -scanbus scsibus3: 3,0,0 300) 'ATAPI ' 'DVD A DH20A1S ' 'UX14' Removable CD-ROM 3,1,0 301) * 3,2,0 302) * 3,3,0 303) * 3,4,0 304) * 3,5,0 305) * 3,6,0 306) * 3,7,0 307) * scsibus6: 6,0,0 600) * 6,1,0 601) 'TOSHIBA ' 'DVD-ROM SD-R5002' '1031' Removable CD-ROM 6,2,0 602) * 6,3,0 603) * 6,4,0 604) * 6,5,0 605) * 6,6,0 606) * 6,7,0 607) * rich@neon:~/Source/cdrtools-2.01.01$ wodim -v speed=1 dev=3,0,0 /home/rich/Downloads/ubuntu-9.10-desktop-i386.iso wodim: No write mode specified. wodim: Asuming -tao mode. wodim: Future versions of wodim may have different drive dependent defaults. TOC Type: 1 = CD-ROM wodim: Operation not permitted. Warning: Cannot raise RLIMIT_MEMLOCK limits.scsidev: '3,0,0' scsibus: 3 target: 0 lun: 0 WARNING: the deprecated pseudo SCSI syntax found as device specification. Support for that may cease in the future versions of wodim. For now, the device will be mapped to a block device file where possible. Run "wodim --devices" for details. Linux sg driver version: 3.5.27 Wodim version: 1.1.9 SCSI buffer size: 64512 Device type : Removable CD-ROM Version : 5 Response Format: 2 Capabilities : Vendor_info : 'ATAPI ' Identification : 'DVD A DH20A1S ' Revision : 'UX14' Device seems to be: Generic mmc2 DVD-R/DVD-RW. Current: 0x0009 (CD-R) Profile: 0x002B (DVD+R/DL) Profile: 0x001B (DVD+R) Profile: 0x001A (DVD+RW) Profile: 0x0016 (DVD-R/DL layer jump recording) Profile: 0x0015 (DVD-R/DL sequential recording) Profile: 0x0014 (DVD-RW sequential recording) Profile: 0x0013 (DVD-RW restricted overwrite) Profile: 0x0012 (DVD-RAM) Profile: 0x0011 (DVD-R sequential recording) Profile: 0x0010 (DVD-ROM) Profile: 0x000A (CD-RW) Profile: 0x0009 (CD-R) (current) Profile: 0x0008 (CD-ROM) Profile: 0x0002 (Removable disk) Using generic SCSI-3/mmc CD-R/CD-RW driver (mmc_cdr). Driver flags : MMC-3 SWABAUDIO BURNFREE FORCESPEED Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R Drive buf size : 988416 = 965 KB Beginning DMA speed test. Set CDR_NODMATEST environment variable if device communication breaks or freezes immediately after that. FIFO size : 12582912 = 12288 KB Track 01: data 689 MB Total size: 792 MB (78:30.24) = 353268 sectors Lout start: 792 MB (78:32/18) = 353268 sectors Current Secsize: 2048 ATIP info from disk: Indicated writing power: 5 Is not unrestricted Is not erasable Disk sub type: Medium Type A, high Beta category (A+) (3) ATIP start of lead in: -11634 (97:26/66) ATIP start of lead out: 359846 (79:59/71) Disk type: Short strategy type (Phthalocyanine or similar) Manuf. index: 3 Manufacturer: CMC Magnetics Corporation Blocks total: 359846 Blocks current: 359846 Blocks remaining: 6578 Forcespeed is OFF. Speed set to 2822 KB/s Starting to write CD/DVD at speed 16.0 in real TAO mode for single session. Last chance to quit, starting real write in 0 seconds. Operation starts. Waiting for reader process to fill input buffer ... input buffer ready. Performing OPC... Starting new track at sector: 0 Track 01: 689 of 689 MB written (fifo 100%) [buf 99%] 16.9x. Track 01: Total bytes read/written: 723488768/723488768 (353266 sectors). Writing time: 310.504s Average write speed 15.8x. Min drive buffer fill was 98% Fixating... Fixating time: 19.522s BURN-Free was never needed. wodim: fifo had 11396 puts and 11396 gets. wodim: fifo was 0 times empty and 11188 times full, min fill was 97%. rich@neon:~/Source/cdrtools-2.01.01$ md5sum /dev/scd0 md5sum: /dev/scd0: Input/output error rich@neon:~/Source/cdrtools-2.01.01$ dd if=/dev/scd0 of=/home/rich/test.iso dd: Lesen von „/dev/scd0“: Input/output error 1412832+0 Datensätze ein 1412832+0 Datensätze aus 723369984 Bytes (723 MB) kopiert, 152,204 s, 4,8 MB/s Now we specify to use SAO mode and suddenly things start working ---------------------------------------------------------------- rich@neon:~/Source/cdrtools-2.01.01$ wodim -v -sao speed=1 dev=3,0,0 /home/rich/Downloads/ubuntu-9.10-desktop-i386.iso TOC Type: 1 = CD-ROM wodim: Operation not permitted. Warning: Cannot raise RLIMIT_MEMLOCK limits.scsidev: '3,0,0' scsibus: 3 target: 0 lun: 0 WARNING: the deprecated pseudo SCSI syntax found as device specification. Support for that may cease in the future versions of wodim. For now, the device will be mapped to a block device file where possible. Run "wodim --devices" for details. Linux sg driver version: 3.5.27 Wodim version: 1.1.9 SCSI buffer size: 64512 Device type : Removable CD-ROM Version : 5 Response Format: 2 Capabilities : Vendor_info : 'ATAPI ' Identification : 'DVD A DH20A1S ' Revision : 'UX14' Device seems to be: Generic mmc2 DVD-R/DVD-RW. Current: 0x0009 (CD-R) Profile: 0x002B (DVD+R/DL) Profile: 0x001B (DVD+R) Profile: 0x001A (DVD+RW) Profile: 0x0016 (DVD-R/DL layer jump recording) Profile: 0x0015 (DVD-R/DL sequential recording) Profile: 0x0014 (DVD-RW sequential recording) Profile: 0x0013 (DVD-RW restricted overwrite) Profile: 0x0012 (DVD-RAM) Profile: 0x0011 (DVD-R sequential recording) Profile: 0x0010 (DVD-ROM) Profile: 0x000A (CD-RW) Profile: 0x0009 (CD-R) (current) Profile: 0x0008 (CD-ROM) Profile: 0x0002 (Removable disk) Using generic SCSI-3/mmc CD-R/CD-RW driver (mmc_cdr). Driver flags : MMC-3 SWABAUDIO BURNFREE FORCESPEED Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R Drive buf size : 988416 = 965 KB Beginning DMA speed test. Set CDR_NODMATEST environment variable if device communication breaks or freezes immediately after that. FIFO size : 12582912 = 12288 KB Track 01: data 689 MB Total size: 792 MB (78:30.21) = 353266 sectors Lout start: 792 MB (78:32/16) = 353266 sectors Current Secsize: 2048 ATIP info from disk: Indicated writing power: 5 Is not unrestricted Is not erasable Disk sub type: Medium Type A, high Beta category (A+) (3) ATIP start of lead in: -11634 (97:26/66) ATIP start of lead out: 359846 (79:59/71) Disk type: Short strategy type (Phthalocyanine or similar) Manuf. index: 3 Manufacturer: CMC Magnetics Corporation Blocks total: 359846 Blocks current: 359846 Blocks remaining: 6580 Forcespeed is OFF. Speed set to 2822 KB/s Starting to write CD/DVD at speed 16.0 in real SAO mode for single session. Last chance to quit, starting real write in 0 seconds. Operation starts. Waiting for reader process to fill input buffer ... input buffer ready. Performing OPC... Sending CUE sheet... Writing pregap for track 1 at -150 Starting new track at sector: 0 Track 01: 689 of 689 MB written (fifo 100%) [buf 99%] 16.9x. Track 01: Total bytes read/written: 723488768/723488768 (353266 sectors). Writing time: 315.241s Average write speed 15.5x. Min drive buffer fill was 99% Fixating... Fixating time: 6.819s BURN-Free was never needed. wodim: fifo had 11396 puts and 11396 gets. wodim: fifo was 0 times empty and 11198 times full, min fill was 97%. rich@neon:~/Source/cdrtools-2.01.01$ dd if=/dev/scd0 of=/home/rich/test.iso 1413064+0 Datensätze ein 1413064+0 Datensätze aus 723488768 Bytes (723 MB) kopiert, 135,412 s, 5,3 MB/s rich@neon:~/Source/cdrtools-2.01.01$ md5sum /dev/scd0 8790491bfa9d00f283ed9dd2d77b3906 /dev/scd0 rich@neon:~/Source/cdrtools-2.01.01$