Here the complete grep cdrom /var/log/syslog:
Jul 7 10:48:44 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 11:35:04 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 11:39:20 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 11:40:38 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 14:10:41 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 14:33:05 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 14:39:05 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 15:42:33 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 16:59:00 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 17:00:36 bilbo automount[31697]: key "cdrom" not found in map source(s).
Jul 7 18:23:37 bilbo automount[31697]: key "cdrom" not found in map source(s).
Best regards,
Reiner