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Thread: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

  1. #1
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    Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    My Dell XPS17 has been running OK with 16.04 and has recently done the upgrade to 18.04.2. The CD/DVD drive worked fine on 16.04 to the extent that this was the device of choice for recording and copying CDs and DVDs. But on 18.04 It records OK and reads DVDs but is glacially slow at reading CDs.

    I've now just got to cutting a heap of CDs and DVDs using the new Xubuntu 18.04.2 AMD64 which seems absolutely OK. CD-Rs and DVD-Rs record at around 2-3MB/s and 3-4MB/s respectively but I noticed that Brasero was taking a longer to compute the checksum for CDs than for DVDs. Doing a test, I found reading back a CD-R takes about 19 minutes for 710MB at 600KB/s, while the same CD took less than 5 mins to record. Using an external Dell USB2 CD/DVD reader the same disc reads in 4 mins at 1.5MB/s. On the other hand Recording and reading back DVDs seems to be OK with a read speed of around 4.7MB/s.

    There's a Win10 system on the same box and I found that the DVD performance was much the same as with Linux while the CD read speed began at 600KB/s quickly building to 2.5MB/s and completing the operation in around 4 mins for 710MB.

    I've tried to look at the settings and as far as I can tell DMA is enabled so I'm a bit foxed.
    The optical drive is a Toshiba Samsung 12.7T SATA DVD+/-RW 8X and the CPU is a series 2 core-i7 with 4GB memory and 2 x 500GB HDDs with plenty of space.

    I'd appreciate any help or pointers as to how I might solve this issue. My next move is to revert to 16.04.4 AMD64 which seemed to work fine.
    Tks in anticipation
    jg

  2. #2
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    The first thing that I would do is to try xfburn. Brasero was always my first choice, but for the last few years I have been using xfburn since I had started having many problems with Brasero.

  3. #3
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    It appears to be a CD read problem. It doesn't matter where or how the CD was cut, Windows, MAC, Ubuntu, or commercial ROM.
    Doing some more tests I have isolated the problem to the Xubuntu 16.04 -> 18.04.2 upgrade process. I did an out of the box 16.04 LTS install and tested it. Then updated it and tested again with both Nemo and Thunar - all OK. Now just upgraded this out-of-the-box installation (ie no customisation beyong displaying seconds in the panel clock) and Thunar is taking 20 mins to read the test CD - still going as I type this !!
    Next I will try a clean/fresh install of 18.04.2 to see if that cures the problem.
    Happy days
    jg

  4. #4
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    I have now done an out-of-the-box fresh install of 18.04.2 selecting 3rd party s/w (as normal for display drivers etc), with no updates and the CD problem is now back, reading at 614.9-615.0 KB/s. 19mins 22 secs for 710MB. This is beginning to look more and more like a software bug in Xubuntu 1804. I have not tried any other flavours but I imagine that they are the same. It's not life threatening but it would be a deal breaker if I played a lot of CDs, eg for music etc.

    Is this something I should report? Not sure of the best way as I'm not particularly technical.

    Anyone know how I might rectify the problem?

    jg
    Last edited by jg1; May 8th, 2019 at 10:46 AM.

  5. #5
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    Hi,

    you could try whether it works better if a userland program is
    in control of the SCSI transactions, rather than the cdrom driver
    of Linux:
    Code:
      xorriso -read_speed max -outdev /dev/sr0 -check_media use=outdev --
    The medium must be a data CD, DVD, or BD. Not an audio CD.

    I get report lines like
    Code:
      xorriso : NOTE : Disc status unsuitable for writing
      Drive current: -outdev '/dev/sr0'
      Media current: CD-RW
      Media status : is written , is closed
      Media summary: 1 session, 157156 data blocks,  307m data,     0 free
      xorriso : UPDATE :      32 blocks read in 3 seconds , 0.2xC
      xorriso : UPDATE :     992 blocks read in 4 seconds , 12.6xC
      xorriso : UPDATE :    2240 blocks read in 5 seconds , 16.5xC
      ...
      xorriso : UPDATE :  101984 blocks read in 64 seconds , 26.6xC
      ...
      xorriso : UPDATE :  155776 blocks read in 89 seconds , 30.2xC
      xorriso : UPDATE :  157156 blocks read in 90 seconds = 23.2xC
      Media checks :        lba ,       size , quality
      Media region :          0 ,     157154 , + good
      Media region :     157154 ,          2 , 0 tao_end
    The texts "NN.NxC" give the measured speed in CD units of 150 KB/s.

    Have a nice day

    Thomas

  6. #6
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    Thomas, tks for your reply. It looks like it's the Lx driver that's adrift in 18.04. After installing xorriso I get much the same output as you:

    jg@jg-XPS17:~$ xorriso -read_speed max -outdev /dev/sr0 -check_media use=outdev --
    xorriso 1.4.8 : RockRidge filesystem manipulator, libburnia project.

    xorriso : NOTE : Disc status unsuitable for writing
    Drive current: -outdev '/dev/sr0'
    Media current: CD-R
    Media status : is written , is closed
    Media summary: 1 session, 347033 data blocks, 678m data, 0 free
    xorriso : UPDATE : 32 blocks read in 3 seconds , 0.2xC
    xorriso : UPDATE : 160 blocks read in 4 seconds , 1.7xC
    xorriso : UPDATE : 512 blocks read in 5 seconds , 4.6xC
    xorriso : UPDATE : 736 blocks read in 6 seconds , 1.8xC
    xorriso : UPDATE : 768 blocks read in 8 seconds , 0.2xC
    xorriso : UPDATE : 928 blocks read in 9 seconds , 2.1xC
    xorriso : UPDATE : 1760 blocks read in 10 seconds , 11.1xC
    xorriso : UPDATE : 2592 blocks read in 11 seconds , 11.1xC
    xorriso : UPDATE : 3456 blocks read in 13 seconds , 11.1xC
    xorriso : UPDATE : 4320 blocks read in 14 seconds , 11.2xC
    ...
    ...
    xorriso : UPDATE : 32800 blocks read in 45 seconds , 12.9xC
    xorriso : UPDATE : 33792 blocks read in 46 seconds , 12.9xC
    xorriso : UPDATE : 34784 blocks read in 47 seconds , 13.0xC
    xorriso : UPDATE : 35776 blocks read in 48 seconds , 13.0xC
    xorriso : UPDATE : 36768 blocks read in 49 seconds , 13.1xC
    xorriso : UPDATE : 37760 blocks read in 50 seconds , 13.1xC
    xorriso : UPDATE : 38752 blocks read in 51 seconds , 13.2xC
    ^C
    UNIX-SIGNAL: SIGINT errno= 2
    xorriso : ABORT : Trying to shut down drive and library
    xorriso : ABORT : Wait the normal burning time before any kill -9

    xorriso : ABORT : Program done. Even if you do not see a shell prompt.

    jg@jg-XPS17:~$

    I suppose the next question is where should I look for a suitable driver and how to install? I can cope with .dev files and ready made install scripts but make and make-install are a step too far for a septagenarian! As far as I can see there's nothing helpful on the Dell website and my searches all bring up Windows stuff.

  7. #7
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    Hi,

    > UNIX-SIGNAL: SIGINT errno= 2

    I assume this was caused by you by e.g. pressing Ctrl+C.
    (If not, then this was not the expected end of the run. We should
    investigate.)


    > I suppose the next question is where should I look for a suitable
    > driver and how to install?

    If the problem is about a driver, then you will need a fix in the Linux
    kernel.

    But for now we only know that the drive is ok with the low level drivers
    of Linux, which transport xorriso's SCSI commands to the drive and then
    brings back the drive's reply.

    The read speed of a drive is a quite persistent setting. It might be that
    some application (maybe even Brasero) did set that speed to 4x.
    If so, then xorriso should now have set the speed to a higher value.
    Then the following dd run would be fast after the xorriso speed test:
    Code:
      dd if=/dev/sr0 bs=2048 count=25000 of=/dev/null
    With my drive it reports
    Code:
      25000+0 records in
      25000+0 records out
      51200000 bytes (51 MB) copied, 17.6107 s, 2.9 MB/s
    2.9 MB/s is about 20x CD speed.
    At 600KB/s = 4x CD speed it would need about 90 seconds.

    ---------------------------------------------------------------------

    If dd is still slow after a xorriso speed test, then something in the
    kernel is wrong. You'd need to tell its exact revision. Like:
    Code:
    $ uname -a
    Linux ts6-sid 4.12.0-1-amd64 #1 SMP Debian 4.12.6-1 (2017-08-12) x86_64 GNU/Linux
    ---------------------------------------------------------------------

    If it appears only after Brasero was run with low burn speed, then i
    have a more convenient suspect. It is the backside of

    "Brasero always burns CD/DVD at max speed (speed option is ignored)"

    https://bugs.launchpad.net/ubuntu/+s...ro/+bug/656297

    Brasero swaps the values for read speed and write speed in libburn call
    burn_drive_set_speed(). If you ask it to burn at 4x speed, then it tells
    libburn to burn at maximum speed and to set read speed to 4x.

    (The problem is not new:
    https://bugs.debian.org/cgi-bin/bugr...cgi?bug=569244
    https://bugs.debian.org/cgi-bin/bugr...cgi?bug=635179
    https://bugs.debian.org/cgi-bin/bugr...cgi?bug=715405
    )

    I just made a test with the speed setting of xorriso. "min" rather than
    "max". The -check_media parameter max_lba=1024 lets xorriso end after
    only 2 MB of reading:
    Code:
    $ xorriso -outdev /dev/sr0 -read_speed min -check_media use=outdev min_lba=0 max_lba=1024
    ...
    xorriso : UPDATE : 32 of 1025 blocks read in 2 s , 0.3xC
    xorriso : UPDATE : 384 of 1025 blocks read in 3 s , 4.5xC
    xorriso : UPDATE : 736 of 1025 blocks read in 4 s , 4.5xC
    xorriso : UPDATE : 1025 of 1025 blocks read in 5 s = 2.9xC
    Media checks :        lba ,       size , quality
    Media region :          0 ,       1025 , + good
    Media region :       1025 ,     156131 , 0 untested
    And now dd is slow:
    Code:
    $ dd if=/dev/sr0 bs=2048 count=25000 of=/dev/null
    25000+0 records in
    25000+0 records out
    51200000 bytes (51 MB) copied, 74.9567 s, 683 kB/s
    Striking ressemblence, isn't it ?
    (One can tell by the drive's noise which speed is set.)

    ---------------------------------------------------------------------

    Have a nice day

    Thomas
    Last edited by scdbackup; May 9th, 2019 at 07:21 PM. Reason: A typo and a clarification

  8. #8
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    Wow ! There's a fair bit to digest here and it's a bit late this evening.
    But what you say seems to make sense on a quick first reading although it doesn't matter where the CD was cut, or if it was a commercial disk. However if Brasero has upset the drive perhaps I'll give xfburn a try and see if that has the same effect. If xorriso has cleared the jam that'd be great. It would mean that I could do more tests and perhaps isolate the problem definitively
    I'll also look at the bug reports.
    Yes the ^C was me stopping the thing as the result was clear and it would save me wading through 710MB worth of terminal output to post my reply.
    I really appreciate the effort you've put in on this.
    At the moment I'm in the middle of synchronising data across 5 machines so I'll pick it up again in the morning.
    Tks again
    jg

  9. #9
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    Hi,

    > Wow ! There's a fair bit to digest here and it's a bit late this evening.

    You have reached the cellar level of support: libburn.


    > However if Brasero has upset the drive perhaps I'll give xfburn a try

    Well, all burn programs which set CD speed have to leave the drive
    with some setting when they end their job. Brasero is special because
    it leaves the read speed at what it intended to use as write speed.

    A search in the Debian source of Xfburn reveils three occassions of the
    libburn call. All three set read speed to 0 (= maximum).
    https://codesearch.debian.net/search...rive_set_speed
    Note the change of position of the 0 in Brasero
    https://codesearch.debian.net/search...rive_set_speed

    So a CD burn run with Xfburn will probably set read speed to maximum,
    as did the xorriso -check_media run. (xorriso is actually a burn program,
    too.)


    Have a nice day

    Thomas

  10. #10
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    Re: Optical Drive slow reading CDs - Dell XPS17 Xubuntu 18.04.2

    I've now done a heap more tests and my summarised findings are as follows. I have the terminal outputs but there is far too much to post here.

    It appears that there are 3 problems at work here.
    1) The CD drive on the XPS17 is a fairly old (7yrs) laptop drive (and therefore flimsy) which occasionally gets read errors (about 1 in 50 CDs inserted) at start-up and initial registration and in responding to the eject command.
    2) Irrespective of the CD/DVD drive being used, Brasero when recording CDs on recent ubuntu distros (1804 and 1604 tested) writes a bad block at the end of the data. This doesn't happen with DVDs or CDs recorded on very old systems (0710 and 1004 were tested). I haven't tested anything in between. This doesn't happen with xorriso which writes clean in every test I've done and reads back marginally quicker than any recorded with Brasero. (Same stock, same hardware recorder, 2-5% quicker)
    3) Xubuntu 18.04 recognises the bad block at the end of a CD read (irrespective of application used) and sets the maximum speed to 4x (600KB/s) so that the next program reads slowly. That can be fixed by using xorriso and cancelling it before the end of the disk. If it runs to the end, the system still sets the drive speed to 4x. Earlier distros don't care so read speeds are max on anything up to 16.04.4 irrespective of what happened on the last run.

    So I think that we have it.
    The problem lies with Brasero and the fact that the new distro recognises and (in my view) overreacts to the error.

    It's a great pity that xorriso is such a fantastic piece of software that it is too complex for routine daily use by a numpty such as myself.

    Question: are there any burners out there that have a simple GUI for handling CDs and DVDs (similar functionality to Brasero) but which have xorriso (or similar engine) as the back end?

    Thomas, this has been a really helpful exercise and my understanding of CDs has increased immeasurably.
    Thank you
    jg

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