[conspire] cd burning giving slight errors

Mon Nov 7 20:52:04 PST 2011

Hi Sean,

Perhaps the problem isn't with the "writing" but with
the "reading": the readom page gave me a clue, when
they say "Using a lower speed may increase the readability of a CD or DVD.".

So I'm giving that a try now, looks good so far.

What tipped me off was, I tried reading the same burned CD twice
in a row at the default (max) speed, and got two slightly different outputs.

So then I thought, perhaps there's excessive vibration
or something causing read errors when the CD motor
spins so fast as it's doing the sequential read.

So perhaps my burns have been OK all along,
it's just the verification step was reading the CD too fast,
and messing up the read!

So now I'm using this command to read "slowly and quietly".

readom speed=1 -v dev=/dev/scd0 f=./testing_read

Thanks for your help!

I was going crazy from puzzlement... :)

But as they say, “Once you eliminate the impossible,
whatever remains, no matter how improbable,
must be the truth.”

I'll try some reads at various higher speeds, to see when the
errors start happening, but at least now I know it's a "hardware
problem", or rather a "newbie misusing the hardware problem".

Cheers,
Peter.

On Mon, Nov 7, 2011 at 11:50 AM, Sean <sean.channel at pacbell.net> wrote:
> Indeed: DAO will add fewer control bits/blocks than TAO. If you can make
> -raw work, I suspect you may have a totally clean checksum.
>
> Funny: I was just looking into PenLUG (seems pretty quiet) before I saw
> your message on conspire.
>
> Best luck,
> _S
>
> On Mon, 2011-11-07 at 01:16 -0800, Peter Knaggs wrote:
>> Hi Sean,
>>
>> Thanks for taking a look. I added the -dao flag,
>> still get errors writing (less, though, only four wrong bytes
>> this time).
>>
>> Output looks as follows.
>>
>> I'm using a CD-RW media now, to avoid making
>> so many coasters.
>>
>> The only thing I can think of that I changed on this
>> system was adding some more memory.
>> I've run the memtest and it passed OK,
>> and I've done repeated parallel kernel builds
>> which ran fine, so I guess the memory is OK.
>>
>> I'm debugging a problem in Inkscape at the
>> moment, quite bizarre behavior, but at least I get
>> to practice debugging a C++ program for a change.
>>   https://bugs.launchpad.net/ubuntu/+source/inkscape/+bug/790130
>>
>> Cheers,
>> Peter.
>>
>> $ wodim speed=1 -dao -v dev=/dev/scd0 -data ubuntu-11.10-desktop-amd64.iso
>> TOC Type: 1 = CD-ROM
>> wodim: Operation not permitted. Warning: Cannot raise RLIMIT_MEMLOCK limits.
>> scsidev: '/dev/scd0'
>> devname: '/dev/scd0'
>> scsibus: -2 target: -2 lun: -2
>> Linux sg driver version: 3.5.27
>> Wodim version: 1.1.11
>> SCSI buffer size: 64512
>> Device type    : Removable CD-ROM
>> Version        : 5
>> Response Format: 2
>> Capabilities   :
>> Vendor_info    : 'ATAPI   '
>> Identification : 'iHAS222   8     '
>> Revision       : '4L01'
>> Device seems to be: Generic mmc2 DVD-R/DVD-RW.
>> Current: 0x000A (CD-RW)
>> 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) (current)
>> Profile: 0x0009 (CD-R)
>> 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 : 1867008 = 1823 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   697 MB
>> Total size:      800 MB (79:20.18) = 357014 sectors
>> Lout start:      801 MB (79:22/14) = 357014 sectors
>> Current Secsize: 2048
>> ATIP info from disk:
>>   Indicated writing power: 3
>>   Reference speed: 6
>>   Is not unrestricted
>>   Is erasable
>>   Disk sub type: High speed Rewritable (CAV) media (1)
>>   ATIP start of lead in:  -11596 (97:27/29)
>>   ATIP start of lead out: 359849 (79:59/74)
>>   1T speed low:  4 1T speed high: 10
>>   2T speed low:  4 2T speed high:  0 (reserved val  6)
>>   power mult factor: 1 5
>>   recommended erase/write power: 4
>>   A1 values: 24 1A C8
>>   A2 values: 26 B2 4A
>> Disk type:    Phase change
>> Manuf. index: 20
>> Manufacturer: Princo Corporation
>> Blocks total: 359849 Blocks current: 359849 Blocks remaining: 2835
>> Forcespeed is OFF.
>> Speed set to 1765 KB/s
>> Starting to write CD/DVD at speed  10.0 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:  697 of  697 MB written (fifo 100%) [buf 100%]  10.6x.
>> Track 01: Total bytes read/written: 731164672/731164672 (357014 sectors).
>> Writing  time:  488.544s
>> Average write speed   9.7x.
>> Min drive buffer fill was 99%
>> Fixating...
>> Fixating time:   15.180s
>> BURN-Free was never needed.
>> wodim: fifo had 11517 puts and 11517 gets.
>> wodim: fifo was 0 times empty and 11312 times full, min fill was 95%.
>>
>>
>>
>>
>> $ readom -v dev=/dev/scd0 f=./testing_read
>> scsidev: '/dev/scd0'
>> devname: '/dev/scd0'
>> scsibus: -2 target: -2 lun: -2
>> Linux sg driver version: 3.5.27
>> Read  speed:  7057 kB/s (CD  40x, DVD  5x).
>> Write speed:  1765 kB/s (CD  10x, DVD  1x).
>> Capacity: 357014 Blocks = 714028 kBytes = 697 MBytes = 731 prMB
>> Sectorsize: 2048 Bytes
>> Copy from SCSI (2,0,0) disk to file './testing_read'
>> end:    357014
>> addr:   357014 cnt: 22
>> Time total: 167.613sec
>> Read 714028.00 kB at 4260.0 kB/sec.
>>
>>
>>
>>
>> $ cmp -l testing_read ubuntu-11.10-desktop-amd64.iso
>>  40983529  73  43
>>  40983545 166 366
>> 191329272  66  62
>> 300276720 130 120
>>
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