udev doesn't create scd* device nodes for scsi cdrom
 

I'm still fairly new to udev type issues. Feel free to direct me to key documentation. My Slack is current and my kernel is 2.6.12.5. My main question is this, how do I mount these scsi CD readers?

I have four old scsi CD readers attached to a Tekram DC315 controller. When I reboot with them attached to the bus, /dev/sg[0-3] are the only device nodes created by udev. Isn't sg* reserved for use with scsi-based CD burners? When I try to mount sg0 (with a CD in it) I get "mount: /dev/sg0 is not a block device". Sure enough an 'ls -l /dev/sg*' produces:

crw-rw---- 1 root cdrom 21, 0 2005-09-15 09:27 /dev/sg0
crw-rw---- 1 root cdrom 21, 1 2005-09-15 09:27 /dev/sg1
crw-rw---- 1 root cdrom 21, 2 2005-09-15 09:27 /dev/sg2
crw-rw---- 1 root cdrom 21, 3 2005-09-15 09:27 /dev/sg3

I think the problem is in either udev.rules or scsi-devfs.sh (not needed for 2.6.x?). Here is a trimmed dmesg output:
dc395x: Tekram DC395(U/UW/F), DC315(U) - ASIC TRM-S1040 v2.05, 2004/03/08
dc395x: Used settings: AdapterID=07, Speed=0(20.0MHz), dev_mode=0x57
dc395x: AdaptMode=0x0f, Tags=4(16), DelayReset=1s
dc395x: Connectors: ext50 Termination: Auto Low High
dc395x: Performing initial SCSI bus reset
scsi0 : Tekram DC395(U/UW/F), DC315(U) - ASIC TRM-S1040 v2.05, 2004/03/08
dc395x: msgin_set_sync: Increase sync nego period to 248ns
dc395x: Target 01: Sync: 248ns Offset 15 (04.0 MB/s)
Vendor: TOSHIBA Model: CD-ROM XM-3501TA Rev: 0315
Type: CD-ROM ANSI SCSI revision: 02
dc395x: msgin_set_sync: Increase sync nego period to 248ns
dc395x: Target 02: Sync: 248ns Offset 15 (04.0 MB/s)
Vendor: TOSHIBA Model: CD-ROM XM-3501TA Rev: 0315
Type: CD-ROM ANSI SCSI revision: 02
dc395x: msgin_set_sync: Increase sync nego period to 248ns
dc395x: Target 03: Sync: 248ns Offset 15 (04.0 MB/s)
Vendor: TOSHIBA Model: CD-ROM XM-3501TA Rev: 0315
Type: CD-ROM ANSI SCSI revision: 02
dc395x: msgin_set_sync: Increase sync nego period to 248ns
dc395x: Target 04: Sync: 248ns Offset 15 (04.0 MB/s)
Vendor: TOSHIBA Model: CD-ROM XM-3501TA Rev: 0315
Type: CD-ROM ANSI SCSI revision: 02
Attached scsi generic sg0 at scsi0, channel 0, id 1, lun 0, type 5
Attached scsi generic sg1 at scsi0, channel 0, id 2, lun 0, type 5
Attached scsi generic sg2 at scsi0, channel 0, id 3, lun 0, type 5
Attached scsi generic sg3 at scsi0, channel 0, id 4, lun 0, type 5

Thanks for any help!

You did enable scsi cd-rom support in your kernel, correct? sg* is generally an underlying interface to scsi-type devices, including USB mass storage devices. Usually, they would be detected properly by udev on most systems.

Wow, that was cool! I've never used a scsi cdrom before so I didn't think to look there. Good catch Matir!

Just compiled sr_mod and tried it. Worked perfectly.

Thank you.

No problem. I'm glad it was that simple. :)