olbigtenor:
> I guess I haven't used the drive/burner since I set up the system about 2
> years ago.
>
> Can't find the DVD drive at all.
> Added libcdio-utils and still no joy.
>
> It has been so long since I've had a problem in this area that I can't
> remember even how to find anything.
> Also can't find anything in /media (!!!).
>
> Suggestions on how to trouble shoot?

Current cd/dvd-drives uses sata connectors, I guess you have one of
theese. If you have an IDE or older one there is an old howto at:
https://tldp.org/HOWTO/text/CDROM-HOWTO

Check that it is properly connected (press eject button, does it
make sound at boot, does the led react).

You need CONFIG_BLK_DEV_SR (selected under "Device Drivers"-> "SCSI
device support"->"SCSI CDROM support" if you are compiling the kernel
yourself. Check if you have it with something like:
$ grep CONFIG_BLK_DEV_SR /boot/config-4.19.277-rt122-rt
CONFIG_BLK_DEV_SR=m
$
in your running kernel's config file (probably have some other name).

 If you have it as a module, check that it is loaded:
  $ lsmod | grep sr_mod 
  sr_mod                 28672  0
  cdrom                  45056  1 sr_mod
  $
 Check that the /dev file is available:
  $ ls -l /dev/scd0
  brw-rw---- 1 root cdrom 11, 0 Apr  5  2022 /dev/scd0
  $
 As can be seen in your kernels source dir's
 Documentation/admin-guide/devices.txt:
...
  11 block      SCSI CD-ROM devices
                  0 = /dev/scd0         First SCSI CD-ROM
                  1 = /dev/scd1         Second SCSI CD-ROM
                    ...

                The prefix /dev/sr (instead of /dev/scd) has been deprecated.
...
 the device file should have major 11, minor 0 unless you have more
 than one drive. Also check that you have rw permissions set.
 As can seen above, my /dev/scd0 belongs to group cdrom, check
 that your user is a member, it is nice to be able to handle it
 as an user:
  $ groups 
  ... cdrom ...

 If you have sg_map available, you can check that the drive is seen:
  # sg_map -x -i | grep cd0
  /dev/sg2  3 0 0 0  5  /dev/scd0  ASUS      DRW-24F1ST   a    1.00
 or simply check with:
  # cat /proc/scsi/scsi 
...
  Host: scsi3 Channel: 00 Id: 00 Lun: 00
    Vendor: ASUS     Model: DRW-24F1ST   a   Rev: 1.00
    Type:   CD-ROM                           ANSI  SCSI revision: 05
...
 And no, you don't need any sg-something installed to use the drive,
 it's just some nice tools for troubleshooting.

To check that you can read anything from the drive, put a cd or dvd
(with something on it) in the drive, wait for the drive to be ready,
and try:
# file -s /dev/scd0
/dev/scd0: UDF filesystem data (version 1.5) 'INGMAR_BERGMAN'
(in this case it is a film on a dvd).
Check you system log to see that there isn't something strange
happening.

Now, to mount the disk, you need a data cd or dvd, you cannot
mount an audio cd (though you can rip it).
And check that the relevant filesystems are available, in
the source under "File systems"->"CD-ROM/DVD Filesystems",
and in the config file:
For data cds:
# grep ISO9 /boot/config-4.19.277-rt122-rt
CONFIG_ISO9660_FS=y
For dvds:
# grep UDF /boot/config-4.19.277-rt122-rt
CONFIG_UDF_FS=y
and possible:
# grep JOLI /boot/config-4.19.277-rt122-rt
CONFIG_JOLIET=y
# grep ZISO /boot/config-4.19.277-rt122-rt
CONFIG_ZISOFS=y
Without the driver for the filesystem, you cannot mount it.

Try to mount it manually:
# mount /dev/scd0 /mnt/
mount: /mnt: WARNING: source write-protected, mounted read-only.
# ls /mnt/
AUDIO_TS VIDEO_TS
# mount | grep scd0
/dev/scd0 on /mnt type udf (ro,relatime,utf8)
#

If all the above is ok, there might be some other problem like with
the automounter (if you use one), ACLs or some other strange things.

I haven't used blue-ray, but I guess the handling is similar.

Regards,
/Karl Hammar