[Pkg-opt-media-team] Bug#709971: dvd+rw-tools: growisofs more then 1 Bluray, since Debian 7 speed collapses

[Thomas Schmitt]

Hi,

meanwhile i am on Debian 8.1, kernel 3.16 and suffer from
the described problems myself.

The behavior resembles old IDE master-slave concurrency
problems. (Disk at /dev/hdc, burner at /dev/hdd.)

There is a coarse workaround from those old times.
cdrecord introduced options -immed and minbuf=, which keep the
drive buffer hungry and so avoid that the kernel has to wait
with a pending WRITE command until the buffer has enough room.

growisofs does not have it, xorriso development just got it,
but cdrskin has it since quite a while.

This allows me to burn with 4x DVD+RW speed, 2.3x BD-RE speed,
and 2.0x BD-RE speed simultaneously (about 24 MB/s in total):
 
  cdrskin -v dev=/dev/sr1 minbuf=65 filename.iso

  cdrskin -v dev=/dev/sr2 minbuf=65 filename.iso

  cdrskin -v dev=/dev/sr4 minbuf=65 filename.iso

Burners are LG GH24NSC0 (SATA), LG GGW-H20L (USB-SATA),
LG BH16NS40 (USB-SATA). Mainboard ASUS P9D WS. 3.4 GHz Xeon.

It does not work well with BD-RE on Optiarc BD-5300S when
Defect Management is disabled. In this case the burner seems
to wait for a full buffer, while libburn waits for half-empty
buffer.
After a few seconds the burner empties the buffer and the
next write-and-wait cycle begins.


Have a nice day :)

Thomas