Messages in this thread | | | From | Joerg Schilling <> | Date | Mon, 13 Feb 2006 11:40:32 +0100 | Subject | Re: CD writing in future Linux (stirring up a hornets' nest) |
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jerome lacoste <jerome.lacoste@gmail.com> wrote:
> On 2/10/06, Joerg Schilling <schilling@fokus.fraunhofer.de> wrote: > > "D. Hazelton" <dhazelton@enter.net> wrote: > > > > > And does cdrecord even need libscg anymore? From having actually gone through > > > your code, Joerg, I can tell you that it does serve a larger purpose. But at > > > this point I have to ask - besides cdrecord and a few other _COMPACT_ _DISC_ > > > writing programs, does _ANYONE_ use libscg? Is it ever used to access any > > > other devices that are either SCSI or use a SCSI command protocol (like > > > ATAPI)? My point there is that you have a wonderful library, but despite > > > your wishes, there is no proof that it is ever used for anything except > > > writing/ripping CD's. > > > > Name a single program (not using libscg) that implements user space SCSI and runs > > on as many platforms as cdrecord/libscg does. > > > I have 2 technical questions, and I hope that you will take the time > to answer them. > > 1) extract from the README of the latest stable cdrtools package: > > Linux driver design oddities ****************************************** > Although cdrecord supports to use dev=/dev/sgc, it is not recommended > and it is unsupported. > > The /dev/sg* device mapping in Linux is not stable! Using dev=/dev/sgc > in a shell script may fail after a reboot because the device you want > to talk to has moved to /dev/sgd. For the proper and OS independent > dev=<bus>,<tgt>,<lun> syntax read the man page of cdrecord. > > My understanding of that is you say to not use dev=/dev/sgc because it > isn't stable. Now that you've said that bus,tgt,lun is not stable on > Linux (because of a "Linux bug") why is the b,t,l scheme preferred > over the /dev/sg* one ?
b,t,l _is_ stable as long as the OS does a reasonable and orthogonal work.
This was true until ~ 2001, when Linux introduced unstable USB handling. Note that this fact is not a failure from libscg but from Linux.
> 2) design question: > > - cdrecord scans then maps the device to the b,t,l scheme. > - the libsg uses the b,t,l ids in its interface to perform the operations > > So now, if cdrecord could have a new option called -scanbusmap that > displays the mapping it performs in a way that people can parse the > output, I think that will solve most issues.
The output of cdrecord -scanbus is already parsable, so what is your point?
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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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