On Jan 07, Erik Andersen wrote:
> On Wed Jan 05, 2000 at 08:41:32PM +0100, Harald Koenig wrote:
> > does anyone know details about Pioneer DVD-303S drive how to set
> > the read speed for DVD media ?
> >
> > with CDROM media I get up to 4.6MB/sec (32x) as specified and expected,
> > but when reading DVD media I only get sustained 2.7 MB/sec (2x) for the
> > whole disc whereas that drive should be 2x-6x (up to 8.1 MB/sec) for DVDs.
> >
> > does anyone have techincal/scsi docs for that drive ?
>
> Have you tried something like:
> /* `0' means auto-selection, you might also try big numbers :) */
> status=ioctl(fd, CDROM_SELECT_SPEED, 0);
thanks for the program (I didn't know about that ioctl before)!
I've tried speed 0 and several other values, it doesn't seem to make
any difference.
in the mean time I got some 3 more DVD (video) disks, and those discs
I can read with higher transfer rates!
the two DVD9 discs (two layers, signle side) read up to 5.4 MB/sec (4x)
while the DVD5 disc (sigle layer, single side) went up to 6.85 MB/sec (5x).
if there are some (rather small) finger prints on the bottom side of
the discs (esp. for DVD9 disks) then the transfer rates dropped
to 2x or even 1x and sometimes I just got read errors!
so it looks like it's mostly a problem with the media itself and my
first disc to test (SuSE 6.3 on DVD) might be the real source,
or maybe it's a difference between video discs and data discs ?!
> Also check out the drive speed field when running
> cat /proc/sys/dev/cdrom/info
> and see if it changes when running the setspeed app.
"drive speed" is always reported being 0 (zero). but looking at the
code in scsi/sr.c get_capabilities() only gets called once at boot time
from sr_finish(), so it's no big surprise that the value
in /proc/sys/dev/cdrom/info doesn't change...
Harald
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