[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: trixie: cdrecord can no longer write to CD



Hi,

Max Nikulin wrote:
> Creation of scd symlinks was removed in (earliest tag "174"):
> d132be4d58 2011-08-12 14:05:19 +0200 Kay Sievers: rules: remove legacy rules
> for cdrom and usb printer

At that time i already had my last SuSE which offered both device
name families. I don't remember whether the duplicates were symbolic
links or just device files with the same major,minor number pairs.


> Earliest usage in udev rules I noticed in (earliest tag "031"):
> 
> 0a8dd7f37c 2004-09-10 21:04:13 -0700 david@fubar.dk: [PATCH] compatibility
> symlinks for udev
> 
> +KERNEL="scd*", NAME="%k", SYMLINK="cdrom%e"

I wonder what "%e" meant, which i cannot find in old and young
man udev.
Can it be a counter which increments with each usage to produce
/dev/cdrom, /dev/cdrom2, /dev/cdrom3, ... ?


> In some cases "sr<n>" were symlinks:
> 
> SUBSYSTEMS=="scsi", KERNEL=="sr[0-9]*",                NAME="scd%n",
> SYMLINK+="sr%n"

I'm unsure whether this wasn't just a preparation for a time when the
kernel would create /dev/scd* instead of /dev/sr*.


> I am puzzled by [a-z] for "sr" and "scd" (wodim uses numbers).
> +BUS="scsi", KERNEL="sr[a-z]",  PROGRAM="/etc/udev/scripts/cdsymlinks.sh
> %k", SYMLINK="%c{1} %c{2} %c{3} %c{4} %c{5} %c{6}"

This is a very interesting rule. But given the condition
KERNEL="sr[a-z]" i doubt that it ever worked for optical drive device
files.

Do i get it right that this rule assumes people to have at most 6
optical drives ? I can attach 7 to my machine: 2 SATA, 4 USB,
1 SanDisk USB stick which fakes a CD-ROM with MS-Windows programs.


> It seems, currently wodim should access only sr<n>, not scd<n> despite what
> kernel docs say.

sr name good, kernel docs bad.


tomas@tuxteam.de wrote:
> There seem to be at least different views on that:
> https://lwn.net/Articles/195167/

It points to
  https://lwn.net/Articles/195169/
which by Joerg Schilling's own writing demonstrates the problem
between him and Debian.
I expect that especially Eduard Bloch was strongly motivated afterwards
to demonstrate that he has the demanded "basic knowledge".


> (gosh, 2006. That's a friggin' long time ago...)

[Nostalgy Warning]

End of 2006 i was busy with enabling DVD recording in libburn after
having implemented CD write type TAO in autumn. It was a wild time.

In 2005 i had asked Andy Polyakov whether dvd+rw-tools could possibly
support CD TAO, which i needed for my scdbackup tool. But he declined
because he considered CD outdated. So i began to beg the libburn
developers to implement TAO. But they were more interested in CD
cloning than in backup on CD. So my cdrskin got a TAO-to-SAO wrapper.
(See man cdrskin, option tao_to_sao_tsize= .)
In august 2006 i was annoyed enough to join the fork of libburn and
then ended up as its main developer.

Meanwhile i believe to qualify for Joerg Schilling's demands towards
burn program developer competence. But i'm too bad as sysadmin to ever
become a Debian Developer.


Have a nice day :)

Thomas


Reply to: