[CentOS] Re: Burning CDs

Wed Jun 15 22:06:47 UTC 2005
Bryan J. Smith <b.j.smith@ieee.org> <thebs413 at earthlink.net>

From: centos at 911networks.com
> Hi,
> I have just installed 4.1 on a new Dell Latitude d610. It does
> not automount the CDs. When I mount the CD manually I get:
> $mount /media/cdrecorder
> mount: block device /dev/hdc is write-protected, mounting read-only

First off, there is a multitude of understanding that is required.
Most consumers are not aware of many differences between CD-R
v. CD-RW access, CD-R v. CD-RW filesystems, etc...

In Windows, some of this is hidden from you to a point, but not all.
E.g., you use a program to "record" whereas you directly access
the drive letter to to "read/write."
Windows only lets you "record" to CD-R (or CD-RW emulating CD-R),
and won't "read/write" to anything but CD-RW (with a non-ISO9660 fs).
These two processes are actually _different_.

What type of CD did you insert?
A CD-RW?  CD-R?  Or CD-ROM?
Also note that CDs are not "formatted read/write" with ISO9660.
ISO9660 is a linear, byte-by-byte track, that is not modifyable
(most specifically, data is a "Yellow Book" track of ISO9660).

You have to use _another_ filesystem to have "read/write."
UDF is its replacement, although almost any filesystem can be used.
As I said, a multitude of understanding.

> The CD writer is an Philips IDE: CDRW/DVD-ROM CDD5263

There is some "read/write" support for CD-RW in kernel 2.6.
I haven't messed with it personally.

Otherwise, you pre-master an .iso file with "mkisofs,"
and then you record with "cdrecord."  There are GUI tools
build around those 2 programs to help you.  That's for CD-R
(or CD-RW emulating CD-R).

> Here is my mtab:
> $ cat /etc/mtab
> /dev/mapper/VolGroup00-LogVol00 / ext3 rw 0 0
> none /proc proc rw 0 0
> none /sys sysfs rw 0 0
> none /dev/pts devpts rw,gid=5,mode=620 0 0
> usbfs /proc/bus/usb usbfs rw 0 0
> /dev/sda1 /boot ext3 rw 0 0
> none /dev/shm tmpfs rw 0 0
> none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0
> /dev/hdc /media/cdrecorder iso9660 ro,nosuid,nodev,user=froggy 0 0
> How do I change /dev/hdc /media/cdrecorder iso9660 ro to rw?

You can't.  You can't really "read/write" anything that is ISO9660.
It is clear that this CD media (CD-RW?) was written as ISO9660.
All you can do is append additional sessions/tracks (if CD-R), or
re-format it (if CD-RW).

These are just things that some Windows tools "hide" from you.
But you still probably need to know about them.

> $ cat /etc/fstab
> # This file is edited by fstab-sync - see 'man fstab-sync' for details
> /dev/VolGroup00/LogVol00 /                       ext3    defaults        1 1
> LABEL=/boot             /boot                   ext3    defaults        1 2
> none                    /dev/pts                devpts  gid=5,mode=620  0 0
> none                    /dev/shm                tmpfs   defaults        0 0
> none                    /proc                   proc    defaults        0 0
> none                    /sys                    sysfs   defaults        0 0
> /dev/VolGroup00/LogVol01 swap                    swap    defaults        0 0
> /dev/hdc                /media/cdrecorder       auto    pamconsole,exec,noauto,managed 0 0

Stick in a new CD-RW media that has been formatted UDF and see what happens.



--
Bryan J. Smith   mailto:b.j.smith at ieee.org