====== cdrom_id ======

  * [[udev]]

For polling devices and getting information sent into udev, the package builds a program called ''cdrom_id''. It's located at ''/lib/udev/cdrom_id''. Running it will give information that is passed to udev triggers.

<code>
/lib/udev/cdrom_id /dev/sr0
</code>

<code>
ID_CDROM=1
ID_CDROM_CD=1
ID_CDROM_DVD=1
ID_CDROM_BD=1
ID_CDROM_MRW=1
ID_CDROM_MRW_W=1
ID_CDROM_MEDIA=1
ID_CDROM_MEDIA_DVD=1
ID_CDROM_MEDIA_STATE=complete
ID_CDROM_MEDIA_SESSION_COUNT=1
ID_CDROM_MEDIA_TRACK_COUNT=1
ID_CDROM_MEDIA_TRACK_COUNT_DATA=1
</code>

You can use it as a poor man's check for a drive status -- see if there's something in there or not.

''ID_CDROM_MEDIA_DVD=1'' will be present if there's a DVD in there (not a CD), and ''ID_CDROM_MEDIA_STATE=complete'' will display if it's finished accessing the device.

However, just because udev is finished, doesn't mean the drive is immediately available. That's why I wrote [[dvd_drive_status]] which will check to see if it's really ready to be read.

Using [[dvd_eject]] will also wait for the drive to be ready, if you use it to close the tray: ''dvd_eject -t''