Re: cdrecord and "get performance" scsi errors
Hi,
> ...
> GET [CURRENT] PERFORMANCE:
Looks like a successful command execution.
I would next try wether growisofs is able to burn with
speeds 2.4 and 4.0.
----------------------------------------------------------
Dirty details:
For the SCSI commands involved let's look into
dvd+rw-tools-7.0/dvd+rw-mediainfo.cpp
(Search for text "GET [CURRENT] PERFORMANCE)
As reference i read
http://www.t10.org/ftp/t10/drafts/mmc5/mmc5r03c.pdf
> Write Performance: 4.0x1385=5540KB/s@[0 -> 2295103]
The CDB would look like
AC 04 00 00 00 00 00 00 nn nn 00 00
in comparison to cdrecord's
AC 00 00 00 00 00 00 00 00 64 03 00
where "nn nn" is the number of allocated descriptor records
which "00 64" in case of cdrecord. dvd+rw-mediainfo inquires
this number first by "00 01" and then allocates the necessary
memory before doing the real descriptor inquiry.
Reading MMC-5: the difference is the parameter Type
in byte number 10. dvd+rw-mediainfo here uses Type 0,
cdrecord uses Type 3.
The value 04 in byte 1 (parameter Data Type) indicates
that dvd+rw-mediainfo is interested in write performance.
We learn from the reply that the write performance is up to
4x DVD speed. Valid over the sector range from 0 to 4.7 GB.
> Speed Descriptor#0: 02/2295103 R@5.4x1385=7449KB/s W@4.0x1385=5540KB/s
> Speed Descriptor#1: 02/2295103 R@5.4x1385=7449KB/s W@2.4x1385=3324KB/s
This stems from a CDB
AC ?? 00 00 00 00 00 00 nn nn 03 00
i.e. with the Type used by the command which has trouble
within cdrecord.
MMC-5 says nothing about the Data Type (byte 1 of the CDB)
with Type 03h. I would expect that ?? is still 04 from the
previous command.
We learn from the reply that write speeds 2.4x and 4.0x could
be set by command B6h SET STREAMING.
(This is what growisofs or my program cdrskin are supposed
to do if you let them burn a DVD+RW and order to use those
speeds. growisofs calculates permissible speeds, cdrskin
lets the drive calculate.)
Have a nice day :)
Thomas
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