Re: Request for cooperation with all burn backends
xiphmont@xiph.org wrote:
> "Very portable" almost alwas == "equally crippled on all platforms".
> I'm so tired of 'very portable' software.
This is not true and there are many software packages that demonstrate
how portable software may work nicely.
> > Have you seen resmgrd? Well, it didn't seem to catch up, but anyway...
> > Why didn't it catch up? If you want my opinion, I think that all
> > attempts to achieve the goal *purely* in user-land are doomed. 2.6
> > O_EXCL on block device appears to be sufficient for intended purpose and
> > I personally would rather prefer it back-ported to 2.4 than some
> > user-land facility.
>
> I had it explained to me in great detail how it was perfectly correct
> to cripple the RedHat version of CDParanoia such that only one could
> ever be running at a time-- because its autoscanning would always
> block on advisory locks if any other program was using any other
> CDROM/DVDROM device on the machine. Why? Because it was somehow
> easier than fixing Nautilus's automount/autoplay tendencies to turn
> every burn into a coaster.
I am not sure whether I understand you correctly, but Redhat also did cripple
cdrecord instead of fixing the newer programs that also like to access CD/DVD
writers.
> I like the idea of having a convention-- but I would argue against it
> locking down devices against all access. A CDROM device is perfectly
> capable of answering, eg, ' are you a cdrom?' whil e burning. I
> realize that deciding what access is 'safe' is underspecified right
> now.
Correct!
This is why I dislike the way of any attempts of locking I did see for now on
Linux. I like to make cdrecord -scanbus work always as expected but be able to
tell the user that a specific drive is currently in use.
> > Note that it doesn't have to be /dev/sg.
>
> /dev/sg is dead. Long live SG_IO.
This way of wording looks to me as if you did not understand the problem.
SG_IO is used in /dev/sg for a ling time and the real problem with SG_IO
is that _other_ related ioctls do not work correctly for all non-/dev/sg
devices.
> I will not be obeying O_EXCL in cdparanoia, at least in its current
> form. However, I also want to make cdparanoia safe in the context of
> cdrom devices ripping.
Off topic:
Monty, do you like to start working on cdparanoia again?
>From my impression, you stopped doing so around y2000.
This is why I did take the paranoia code 4.5 years ago, made it portable and
a library that is now used by cdda2wav. Since then, I did fix several minor bugs
in the code and you should have a look at the current libparanoia, to see what
I did. Please also note that the basic CD reading stuff in cdparanoia is still
similar to what cdda2wav did in 1997. Cdda2wav did evolve a lot since then and
this is why cdda2wav may currently read a lot more CDs than cdparania currently
does. This in special is true for "unCDs".
BTW: I am planning to add C2-pointer support to libparanoia next year.
partially back...: I am planning to change all users of libscg to scan the bus
by default and in case that there is only a single CD/DVD device in the system,
to use this device. This unfortunately is impossible on Linux since device
aliasing was added and since not all SG_IO related ioctls return correct and
complete information in all cases anymore....
Jörg
--
EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
js@cs.tu-berlin.de (uni)
schilling@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily
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