Re: trixie: cdrecord can no longer write to CD
On 24/11/2025 15:20, Thomas Schmitt wrote:
Max Nikulin wrote:
I am lost which way /dev/scd<n> were created in the past.
Digging in my dim memories ...
It happened after Linux gave up the large unconditional collection of
device files in favor of files which show up only if they have a drive
attached.
I first experienced that novel behavior with a USB attached CD drive.
It may be that HAL, kindof a predecessor of udev, was already at work.
(It was an infamous groper of CD drives in the middle of burn runs
which resulted in wasted CD-R media.)
TLS certificate of cgit.freedesktop.org (where HAL was hosted) has
expired. I have a systemd clone and it contains udev history, so I have
tried it first.
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
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"
In some cases "sr<n>" were symlinks:
SUBSYSTEMS=="scsi", KERNEL=="sr[0-9]*", NAME="scd%n", SYMLINK+="sr%n"
I am puzzled by [a-z] for "sr" and "scd" (wodim uses numbers).
+# cdrom symlinks and other good cdrom naming
+BUS="ide", KERNEL="hd[a-z]", PROGRAM="/etc/udev/scripts/cdsymlinks.sh %k", SYMLINK="%c{1} %c{2} %c{3} %c{4} %c{5} %c{6}"
+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}"
+BUS="scsi", KERNEL="scd[a-z]", PROGRAM="/etc/udev/scripts/cdsymlinks.sh %k", SYMLINK="%c{1} %c{2} %c{3} %c{4} %c{5} %c{6}"
These parts of code are rather volatile, I am unsure if it was a part of
some release or it was just temporary state of a development branch.
It seems, currently wodim should access only sr<n>, not scd<n> despite
what kernel docs say. I would not be surprised if there were periods of
scd without sr or vice versa in the past. At least a comment should
mention scd.
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