Re: CD writing in future Linux (stirring up a hornets' nest)

[D. Hazelton]

On Saturday 18 February 2006 12:15, Gene Heskett wrote:
> On Saturday 18 February 2006 07:06, Christoph Hellwig wrote:
>
> cat /proc/sys/dev/cdrom/info
> CD-ROM information, Id: cdrom.c 3.20 2003/12/17
>
> drive name:             hdc
> drive speed:            48
> drive # of slots:       1
> Can close tray:         1
> Can open tray:          1
> Can lock tray:          1
> Can change speed:       1
> Can select disk:        0
> Can read multisession:  1
> Can read MCN:           1
> Reports media changed:  1
> Can play audio:         1
> Can write CD-R:         1
> Can write CD-RW:        1
> Can read DVD:           1
> Can write DVD-R:        1
> Can write DVD-RAM:      0
> Can read MRW:           1
> Can write MRW:          1
> Can write RAM:          1

Ah, so it does already exist. Only thing left might be to stick the 
manufacturer, serial and misc. data into sysfs

> But I fail to see where this would help to 'find' the right device to
> write to, other than the obvious prefixing of '/dev/' to $drive name.
> We already knew that, and in fact it works very well. Please explain to
> Joerg in one syllable words he might, if he wanted to, understand.

Well, in this case I'm actually trying to work with Joerg to produce a patch 
that unifies the ATAPI and SCSI busses inside his program. One thing this 
does is help to locate available drives. Negates the need to scan the entire 
ATA/ATAPI bus for drives. However, since, as Joerg has pointed out, libscg is 
a generic SCSI system, it doesn't negate it's need to scan the entire SCSI 
bus. It's use as a backend to cdrecord is incidental in this case.

> Also, I'm fuzzy about the last 3, so defining those might help me
> understand.

I've seen the "MRW" stuff in some of the specs, but had to check the net to 
find out what it was. MRW is the Mt. Rainier format - basic support was added 
by Jens back in 2.4.19 according to the archives. 
(http://www.ussg.iu.edu/hypermail/linux/kernel/0203.2/1214.html)

I'm not positive, but the "Can Read RAM" line might refer to DVD-RAM type 
discs

DRH
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