>> Maybe I need to get a non-tweaked cdrecord:
>> ZY$?: Operation not permitted. WARNING: Cannot set RR-scheduler
>> ZY$?: Permission denied. WARNING: Cannot set priority using
>> ZY$?: WARNING: This causes a high risk for buffer underruns.
>> Cdrecord-Clone-dvd 2.01a27 (i686-suse-linux) Copyright (C) 1995-2004
>> J?rg Schilling
>> Note: This version is an unofficial (modified) version with DVD support
>> Note: and therefore may have bugs that are not present in the original.
>> Note: Please send bug reports or support requests to
>> Note: The author of cdrecord should not be bothered with problems in
>> this version.
>> cdrecord: No such file or directory. WARNING: Cannot do mlockall(2).
>> cdrecord: WARNING: This causes a high risk for buffer underruns.
>> cdrecord: Warning: not running as root user, fs= option ignored.
> The thing tells pretty clearly that it cannot obtain
> enough priority to prevent buffer underruns. It also
> shows I/O errors (probably buffer underruns).
> You clearly need superuser rights to succeed.
> Please try again with other activities (such as
> networking) shut off and with root privileges.
Thanks for the reply.
However, it is not cdrecord that is actually failing. It is the read of
the drive *afterward*. That gives IO errors.
Here's what happened:
1. Start Linux, do md5sum on /dev/cdrecorder -- success, no errors.
2. Burn with cdrecord -- success, no errors and reports from cdrecord
(not shown in my post) indicated no buffer underruns, despite the warning.
3. Do md5sum on /dev/cdrecorder -- errors, though the same disk after a
reboot will md5sum just fine.
Conclusion: I think cdrecord is doing something at the driver level,
that is not getting reset, leaving the drive in a strange state. Oddly,
I CAN mount the disk and read the files, without errors though I should
qualify this by saying that I haven't tried reading all the files' data,
rather I just see the directory structure intact, and a randomly
selected file reads OK. But since the disk always md5sums correctly
after a reboot, I think this proves that the data is in fact intact.
Furthermore, on a different machine with a different drive, the same
*software* setup doesn't have a problem with md5sums after the burns.
This other machine also gives the warnings from cdrecord seen above.
(See example below.)
I think I will do the following:
1. try running cdrecord as root just to see if it makes a difference
2. try a different physical drive in the problem machine. If that
makes the problem go away, I'd be convinced that there is a driver level
or cdrecord interaction with driver problem, that is specific to that
Example of operation on different machine, also not as root (some excess
> cdrecord dev=$CDRW_SCSI_DEV -v blank=fast -dao ~/cd-rw/full.backup.iso
ZY$?: Operation not permitted. WARNING: Cannot set RR-scheduler
ZY$?: Permission denied. WARNING: Cannot set priority using setpriority().
ZY$?: WARNING: This causes a high risk for buffer underruns.
Cdrecord-Clone-dvd 2.01a27 (i686-suse-linux) Copyright (C) 1995-2004
Note: This version is an unofficial (modified) version with DVD support
Note: and therefore may have bugs that are not present in the original.
Note: Please send bug reports or support requests to
Note: The author of cdrecord should not be bothered with problems in
TOC Type: 1 = CD-ROM
cdrecord: No such file or directory. WARNING: Cannot do mlockall(2).
cdrecord: WARNING: This causes a high risk for buffer underruns.
cdrecord: Warning: not running as root user, fs= option ignored.
scsibus: 3 target: 0 lun: 0
Linux sg driver version: 3.5.27
Using libscg version 'schily-0.8'.
cdrecord: Warning: using inofficial libscg transport code version
1.80 04/03/08 Copyright 1997 J. Schilling').
SCSI buffer size: 64512
Device type : Removable CD-ROM
Version : 0
Response Format: 2
Vendor_info : 'LITE-ON '
Identifikation : 'LTR-52327S '
Revision : 'QS53'
Device seems to be: Generic mmc CD-RW.
Profile: 0x000A (current)
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 : 1419264 = 1386 KB
FIFO size : 4194304 = 4096 KB
Track 01: data 560 MB
Total size: 644 MB (63:48.20) = 287115 sectors
Lout start: 644 MB (63:50/15) = 287115 sectors
Current Secsize: 2048
ATIP info from disk:
Indicated writing power: 1
Reference speed: 0
Is not unrestricted
Disk sub type: Ultra High speed Rewritable media (2)
ATIP start of lead in: -11076 (97:34/24)
ATIP start of lead out: 336075 (74:43/00)
1T speed low: 16 1T speed high: 16
2T speed low: 8 2T speed high: 24
power mult factor: 4 5
recommended erase/write power: 1
A1 values: 66 4A 99
A2 values: 38 80 00
A3 values: 04 C4 A0
Disk type: Phase change
Manuf. index: 11
Manufacturer: Mitsubishi Chemical Corporation
cdrecord: Cannot get next writable address for 'invisible' track.
cdrecord: This means that we are checking recorded media.
cdrecord: This media cannot be written in streaming mode anymore.
cdrecord: If you like to write to 'preformatted' RW media, try to blank
Forcespeed is OFF.
Starting to write CD/DVD at speed 24.0 in real SAO mode for single ses
Last chance to quit, starting real write 0 seconds. Operation starts
Waiting for reader process to fill input buffer ... input buffer ready.
Blanking PMA, TOC, pregap
Blanking time: 11.491s
BURN-Free is OFF.
Sending CUE sheet...
Writing pregap for track 1 at -150
Starting new track at sector: 0
Track 01: 560 of 560 MB written (fifo 100%) [buf 99%] 24.6x.
Track 01: Total bytes read/written: 588011520/588011520 (287115 sectors
Writing time: 171.403s
Average write speed 22.3x.
Min drive buffer fill was 83%
Fixating time: 4.051s
cdrecord: fifo had 9262 puts and 9262 gets.
cdrecord: fifo was 0 times empty and 7206 times full, min fill was 85%.
> cdrecord dev=$CDRW_SCSI_DEV -eject
> cdrecord dev=$CDRW_SCSI_DEV -load
Press Enter or close when done...
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA