accessing my USB DVD/CDRW

Forum: HD Install
Topic: accessing my USB DVD/CDRW
started by: dslrgm

Posted by dslrgm on Aug. 24 2007,21:13

I am missing something obvious. Of course I am coming from RHEL/Centos, so it might just have the wrong glasses on.

The hardware IS problematic. It is one of the decTOPs that I have installed Frugal on the HD.

So I boot from the HD.

Where is my USB CD? The mount button in the lower left gives an error when I click on it.

ls /cdrom1

is empty. But the CD is there (Trixbox 2.3.0.1 install ISO).

I can't find anything familiar to get to the CD.

thanks.

Posted by stupid_idiot on Aug. 25 2007,00:22

hi dslrgm:
Did you mean to say '/mnt/cdrom1', and not '/cdrom1'?
'/cdrom' is where the DSL compressed-loop filesystem image is mounted; '/cdrom1' doesn't exist.

Anyway:
'/mnt/cdrom' and '/mnt/cdrom1' exist by default.
So it doesn't mean your drive is usable (yet).
IIRC, DSL uses '/dev/scd*' even for IDE cdroms, which means all cd drives use scsi emulation by default. This makes sense since scsi emulation is necessary on 2.4.x kernels for cd burning (cdrecord, etc) to work.
According to this page
(< http://tldp.org/HOWTO/SCSI-2.4-HOWTO/sr.html >),
the device files (on the 2.4 kernel) for usb cdroms are either '/dev/scd*' or '/dev/sr*'.
So you could try either one:

Code Sample

mount /dev/scd[*] /mnt/cdrom
mount /dev/sr[*] /mnt/cdrom

Before you do this, check using

Code Sample

lsmod

that the 'usb-storage' driver is loaded.
If not, do

Code Sample

modprobe usb-storage

before you try to mount.
Also, there's alot of information here regarding usb devices:
< http://www.linux-usb.org/USB-guide/book1.html >
Subsection - USB mass storage (including cdroms):
< http://www.linux-usb.org/USB-guide/x498.html >

Posted by stupid_idiot on Aug. 25 2007,00:28

Code Sample

lsusb

will show you the usb devices present on your system.
If your device is shown here, it does not guarantee that it can be mounted.
It is possible that the 'usb-storage' driver has not been loaded.
In this case, if you scan for so-called scsi drives using

Code Sample

cdrecord -scanbus

nothing will be shown.
However, after you do

Code Sample

modprobe usb-storage

then

Code Sample

cdrecord -scanbus

should give results.

Posted by jpeters on Aug. 25 2007,04:46

Quote (stupid_idiot @ Aug. 24 2007,20:22)

According to this page
(< http://tldp.org/HOWTO/SCSI-2.4-HOWTO/sr.html >),
the device names (on the 2.4 kernel) for usb cdroms are either 'scd*' or 'sr*'.

My iomega USB cdrom mounts with /mnt/cdrom1.

Posted by stupid_idiot on Aug. 25 2007,06:27

Oh, I realize my mistake:
'/cdrom' is where the DSL compressed-loop filesystem image is mounted.
The mountpoints for cdrom drives are '/mnt/cdrom' and '/mnt/cdrom1'.
Very sorry about this.
I've corrected my previous post.
Thanks jpeters.