Hi,
ÿ ÿHow do I get Debian to recognize when an external DVD is connected?

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Gregory Forster wrote:

Hi,
ÿ ÿHow do I get Debian to recognize when an external DVD is connected?

what do you want to accomplish? what desktop are you
using?

it is probably detected when you plug it in or turn on
the machine if it is already connected and powered up.

if it isn't powered up then when you turn it on it
should come up and be detected, but it also depends upon
what you have set up in various places we can't really
know about.

if anything you can set up something once you know what
is happening: a udev rule, a systemd unit or a script
to run from a shell or ...

looking at the log files and finding out what devices
are detected when you turn them on and off will often
provide some help.

lsusb, lsblk are two of the most commonly used ones
that i use when needed.


songbird

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

At Sun, 12 Apr 2026 07:53:45 -0500 Gregory Forster <debian4greg@gmail.com> wrote:

Hi,
How do I get Debian to recognize when an external DVD is connected?

What do you mean by "recognize"?

The Linux USB subsystem should do this automagically. udev has been doing this since kernel version 2.6 or so. I am assuming you are talking about a USB connected drive. I don't know if SATA hot-swap applies to DVD players (if you are using an eSATA DVD player).

If you mean something like a disk icon showing up on your desktop or something, that will depend on your desktop subsystem.

--
Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
heller@deepsoft.com -- Webhosting Services


--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

I guess I was expecting recognition like when USB flash drives, hard
drives, my voice recorder, my cell phone are connected,

So, I tried it again. No, it wasn't recognized, but it seems to work.

On 4/12/26 9:05 AM, Robert Heller wrote:

At Sun, 12 Apr 2026 07:53:45 -0500 Gregory Forster <debian4greg@gmail.com> wrote:

Hi,
How do I get Debian to recognize when an external DVD is connected?

What do you mean by "recognize"?

The Linux USB subsystem should do this automagically. udev has been doing this
since kernel version 2.6 or so. I am assuming you are talking about a USB connected drive. I don't know if SATA hot-swap applies to DVD players (if you are using an eSATA DVD player).

If you mean something like a disk icon showing up on your desktop or something, that will depend on your desktop subsystem.

--
-- Greg

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

So, I tried it again. No, it wasn't recognized, but it seems to work.

Strongly suggest that your definition of "recognized" is very different
from mine.


=== Stefan

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Sun, Apr 12, 2026 at 04:40:36PM -0500, Gregory Forster wrote:

I guess I was expecting recognition like when USB flash drives, hard drives, my voice recorder, my cell phone are connected,

So, I tried it again. No, it wasn't recognized, but it seems to work.

You tried lsusb?
Or dmesg -w while plugging in the device.
Cheers
--
t


--- PyGate Linux v1.5.14
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

At Mon, 13 Apr 2026 09:27:25 -0500 debian-user@lists.debian.org wrote:

On Sun 12 Apr 2026 at 16:40:36 (-0500), Gregory Forster wrote:

I guess I was expecting recognition like when USB flash drives, hard drives, my voice recorder, my cell phone are connected,

All those devices probably have some mass storage onboard, so if
you're running a DE or an automounter, you may see some effect,
like drawing an icon on the screen.

More formally, what is going in is that the graphical file manager (eg the Linux equivelant of MS-Windows' "Windows Explorer" or MacOS's "Finder") is displaying an icon for a "file system". Flash drives and external hard drives almost always have a factory installed [empty] file system and smart phones have an internal file system where the phones operating system resides. An optical drive *by itself* never has a file system. Only when a disk is
inserted is there the *possibility* of a file system. Generally speaking audio CDs don't have a "real" file system, just a collection of audio tracks (sort
of like partitions containing "raw data"). Movie disks do have a file system, but it won't be flagged as a "data" disk and the graphical file manager might not bother with an icon. If you have an audio or movie viewer application installed, these apps might "recognize" these disks as a playable disk, but
the graphical file manager might not show anything -- some do and some don't and it might be a configuration option.

So, I tried it again. No, it wasn't recognized, but it seems to work.

If it wasn't recognised, it wouldn't work. Yes, it was recognised, but
there was as little reason to disturb the user as there is when the
system recognises all the builtin devices shortly after booting up.

To convince yourself, type:

$ udevadm monitor -u -p -s block/disk
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing

Then plug in the device. You'll get some paragraphs from udev like:

UDEV [2685.710126] add /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/host6/target6:0:0/6:0:0:0/block/sr1 (block)
ACTION?d
DEVPATH=/devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/host6/target6:0:0/6:0:0:0/block/sr1
SUBSYSTEM=block
DEVNAME=/dev/sr1
[ ƒ?? ]

and, instead:

[ ƒ?? ]
ACTION=remove
[ ƒ?? ]

when you unplug it.

You can read what reacts to these events in /usr/lib/udev/rules.d/,
and write your own versions in /etc/udev/rules.d/, the two directories
being merged numerically to determine the order of running the rules
with each event.

You can capture more events with just udevadm monitor -u -p
For example, type that line and then unplug your mouse or keyboard momentarily (switch it off and on if wireless).

Happy hacking.

Cheers,
David.

--
Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
heller@deepsoft.com -- Webhosting Services


--- PyGate Linux v1.5.14
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-04-12, Stefan Monnier <monnier@iro.umontreal.ca> wrote:

So, I tried it again. No, it wasn't recognized, but it seems to work.

Strongly suggest that your definition of "recognized" is very different
from mine.

If it works, I'm satisfied.

=== Stefan

--- PyGate Linux v1.5.14
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

CGS [2026-04-13 15:28:42] wrote:

On 2026-04-12, Stefan Monnier <monnier@iro.umontreal.ca> wrote:

So, I tried it again. No, it wasn't recognized, but it seems to work.

Strongly suggest that your definition of "recognized" is very different
from mine.

If it works, I'm satisfied.

My definition works, yes (at least for me).
So I guess you're satisfied? ?


=== Stefan

--- PyGate Linux v1.5.14
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)