Re: Low burning speed
Hi,
Tomasz Kaptocz wrote:
> 181403648/4220336128 ( 4.3%) @6.0x, remaining 11:30 RBU 99.1% UBU 84.6%
> 209125376/4220336128 ( 5.0%) @6.0x, remaining 10:52 RBU 100.0% UBU 80.8%
> 232062976/4220336128 ( 5.5%) @5.0x, remaining 10:53 RBU 100.0% UBU 73.1%
> 241631232/4220336128 ( 5.7%) @2.1x, remaining 11:15 RBU 98.9% UBU 30.8%
> 256933888/4220336128 ( 6.1%) @3.3x, remaining 11:18 RBU 100.0% UBU 19.2%
The drive seems to be willing to run at the speed which
is announced for the first part of the media: 6.0x.
The fact that the drive buffer (UBU) after a short time
of burning has less than 20 % fill indicates that there
is a problem with data transfer from computer to drive.
Effective throughput seems to be about 4.3 MB/second.
This incident here looks quite strange:
> 1882193920/4220336128 (44.6%) @3.7x, remaining 8:10 RBU 100.0% UBU 26.9%
> 1883176960/4220336128 (44.6%) @0.2x, remaining 8:13 RBU 100.0% UBU 100.0%
> 1883176960/4220336128 (44.6%) @0.0x, remaining 8:17 RBU 100.0% UBU 100.0%
> 1886191616/4220336128 (44.7%) @0.7x, remaining 8:21 RBU 100.0% UBU 15.4%
Drive buffer is reported as full, but there is no
substantial data transfer for a short time.
This cannot be blamed on a bad throughput.
Maybe the drive buffer ran empty and the drive
decided to wait until it is at 100 % again.
Then it needed some time to speed up disc rotation
again.
Experiment proposal:
Would it work with better speed if you do not
burn the ISO image on the fly but first generate
it in a disk file and afterwards burn that file
to media ?
For simplicity you could omit the mkisofs run
and just create a dummy file of 4 GB:
dd if=/dev/zero of=/tmp/4gb_of_zeros bs=1M count=4096
(1 GB = count=1024 should suffice too.)
This file could be burned to media by various programs:
growisofs -use-the-force-luke -Z /dev/sr0=/tmp/4gb_of_zeros
cdrecord -v dev=/dev/sr0 /tmp/4gb_of_zeros
cdrskin -v dev=/dev/sr0 /tmp/4gb_of_zeros
Of course, the result will not be mountable but only
bear a lot of 0-bytes. One can verify success by
diff /dev/sr0 /tmp/4gb_of_zeros
which might report surplus bytes on /dev/sr0.
Have a nice day :)
Thomas
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