Hugo,You've provided a lot of information, but some of the important information is missing. Such as:
What drive are you using? What operating system? Are you sure that the drive is supposed to support DVD+R?If the drive is known to support DVD+R, then get hold of a DVD+R that was burned on another machine, and can be read properly by the machine that burned it. Then test it on your machine. If you see read errors, then clearly the burning software is not the culprit. Or, anyway, your machine is not working well enough to know whether the burning software is at fault or it simply can't read any DVD+R.
That's where I would start. It would divide the problem into one of two categories. Either the machine can read DVD+R, but not write it, or the machine can neither read nor write the DVD+R.
If it can't read a known good DVD+R, there isn't much point in mucking around with the burning software, or the blank media either. If the machine burns at 4x when you instruct it to burn at 1x, that's a strong indication of a firmware problem, because is isn't paying any attention to the speed at which you suggested it should burn.
Also, see if another machine that is capable of reading DVD+R can read the DVD+R that you've burned (you have 15 to choose from; try at least two).
Since you mentioned dmesg, I'll assume you are using linux. It might be worthwhile to rebuild the kernel for IDE/SCSI emulation support, use the command line argument telling it to tread /dev/hdc as a SCSI device, and see what happens when you burn.
Hugo van der Merwe wrote:
I'm new to DVD writing. I've now got about 15 badly written DVDs. growisofs does not give any bad-looking output, everything looks great, but the DVDs all have some files that cannot be read. These kinds of errors appear in dmesg when trying to read the DVDs I've written:Buffer I/O error on device hdc, logical block 226047 hdc: command error: status=0x51 { DriveReady SeekComplete Error } hdc: command error: error=0x54 ide: failed opcode was 100 end_request: I/O error, dev hdc, sector 904192 Buffer I/O error on device hdc, logical block 226048 hdc: command error: status=0x51 { DriveReady SeekComplete Error } hdc: command error: error=0x54 ide: failed opcode was 100 end_request: I/O error, dev hdc, sector 904196 Buffer I/O error on device hdc, logical block 226049 hdc: command error: status=0x51 { DriveReady SeekComplete Error } hdc: command error: error=0x54 ide: failed opcode was 100 I miss the output of cdrecord telling me about possible buffer underruns and the like. ("Burn-free was used 3 times" etc.) What can I do? I've tried giving the -speed=1 parameter, it still writes at about 4x. I am using Verbatim DVD+Rs, I suppose I should try something else. What elseis "good quality"? Might Verbatim DVD-Rs work better? Or should I be trying a different drive? (Or install Windows to try other software - might that help at all, or is this purely a hardware problem?)Thanks, Hugo