Hi

I'm running Slackware 12.0, kernel 2.6.21.5. I have a dvd and a cd
drive. My problem is that the link /dev/cdrom intermittently points
to /dev/hdd, i.e.:

%~$ ls -l /dev/cdrom
lrwxrwxrwx 1 root root 3 2008-01-08 07:13 /dev/cdrom -> hdd

rather than /dev/hdc.

This is after I created the file:

/etc/udev/rules.d/10-local.rules

which contains:

KERNEL=="hdc", SYMLINK="cdrom"

Before I created this file, it constantly pointed to /dev/hdd. Now,
it
seems to alternate daily between hdc and hdd. When I do:

udevtest /sys/block/hdd

I get:

.....

update_link: found '/block/hdc' for 'cdrom'
update_link: compare priority of '/block/hdc' 0 > 0
update_link: found '/block/hdd' for 'cdrom'
update_link: compare (our own) priority of '/block/hdd' 0 >= 0
update_link: 'cdrom' with target 'hdd' has the highest priority 0,
create it
.....

which seems to say that there is still some file trying to push /dev/
hdd as
the link from /dev/cdrom. One other confusing thing is that the
timestamp
in:

lrwxrwxrwx 1 root root 3 2008-01-08 07:13 /dev/cdrom -> hdd

for the created link is 07:13, and the computer was not on at this
time.

So can anyone tell me how to make the link with /dev/hdc permanent?
Thanks.

On Jan 9, 1:46 pm, "Mr. Usenet" <spamthe...@yahoo.com> wrote:
>
....
> So can anyone tell me how to make the link with /dev/hdc permanent?
> Thanks.

If you *always* want your cdrom to point to /dev/hdc AND you do not
need dynamic assignment of you cdrom device... then there is no need
to use udev for this
so remove *your* changes from /etc/udev/rules.d, and instead do the
following:

Make sure user.group of /dev/hdc is root.cdrom
(ls -l /dev/hdc = brw-rw---- 1 root cdrom 22, 64 2008-01-09 05:58 /dev/
hdc)

Make a symlink /dev/cdrom -> /dev/hdc
(ls -l /dev/cdrom = lrwxrwxrwx 1 root root 3 2008-01-09 05:58 /dev/
cdrom -> hdc)

In fstab uncomment the line (or add the line):
/dev/cdrom /mnt/cdrom iso9660 noauto,user,ro 0 0

This should do what you need.

toshiro wrote:
> On Jan 9, 1:46 pm, "Mr. Usenet" <spamthe...@yahoo.com> wrote:
> >
> ...
> > So can anyone tell me how to make the link with /dev/hdc permanent?
> > Thanks.
>
> If you *always* want your cdrom to point to /dev/hdc AND you do not
> need dynamic assignment of you cdrom device... then there is no need
> to use udev for this
> so remove *your* changes from /etc/udev/rules.d, and instead do the
> following:
>
> Make sure user.group of /dev/hdc is root.cdrom
> (ls -l /dev/hdc = brw-rw---- 1 root cdrom 22, 64 2008-01-09 05:58 /dev/
> hdc)
>
> Make a symlink /dev/cdrom -> /dev/hdc
> (ls -l /dev/cdrom = lrwxrwxrwx 1 root root 3 2008-01-09 05:58 /dev/
> cdrom -> hdc)
>
> In fstab uncomment the line (or add the line):
> /dev/cdrom /mnt/cdrom iso9660 noauto,user,ro 0 0
>
> This should do what you need.

Thanks for the reply. I'm wondering though, if the above will work
since
the system was already set similar to what you have said. fstab has
the
lines you mention, and I get the following when I do:

$ ls -l /dev/hdc
brw-rw-rw- 1 root cdrom 22, 0 2008-01-10 01:08 /dev/hdc
$ ls -l /dev/cdrom
lrwxrwxrwx 1 root root 3 2008-01-10 01:08 /dev/cdrom -> hdc

The only difference is the permissions on my /dev/hdc which is "brw-rw-
rw-"
rather than "brw-rw----". And if I remove rw from o, i.e.

chmod o-rw /dev/hdc

I'm worried I won't be able to use the cdrom writer.
I can remove the rules I added to make things almost exactly like
before, but I think it will just mean that /dev/cdrom will
permanently point to /dev/hdd which was my initial problem.

"Mr. Usenet" <spamtheftc@yahoo.com> writes:


> So can anyone tell me how to make the link with /dev/hdc permanent?
> Thanks.

IMO, dump udev. How many times does one really add devices to their system?
udev takes something trivial, adds a bunch of config files, makes it
more complex, and then fails to work. Progression, backwards.


--
[** America, the police state **]
Whoooose! What's that noise? Why, it's US citizen's
rights, going down the toilet with Bush flushing.
http://www.wired.com/politics/securi...007/08/wiretap
http://www.hermes-press.com/police_state.htm

On 2008-01-10, toshiro <manimotomushi@hotmail.com> wrote:
> On Jan 9, 1:46 pm, "Mr. Usenet" <spamthe...@yahoo.com> wrote:
>>
> ...
>> So can anyone tell me how to make the link with /dev/hdc permanent?
>> Thanks.
>
> If you *always* want your cdrom to point to /dev/hdc AND you do not
> need dynamic assignment of you cdrom device... then there is no need
> to use udev for this
> so remove *your* changes from /etc/udev/rules.d, and instead do the
> following:
>
> Make sure user.group of /dev/hdc is root.cdrom
> (ls -l /dev/hdc = brw-rw---- 1 root cdrom 22, 64 2008-01-09 05:58 /dev/
> hdc)
>
> Make a symlink /dev/cdrom -> /dev/hdc
> (ls -l /dev/cdrom = lrwxrwxrwx 1 root root 3 2008-01-09 05:58 /dev/
> cdrom -> hdc)
>
> In fstab uncomment the line (or add the line):
> /dev/cdrom /mnt/cdrom iso9660 noauto,user,ro 0 0
>
> This should do what you need.


That's great until the OP reboots - it's not going to persist.
The proper way is to handle it with udev.
I'll post that in just a moment to the original post.

-RW

["Followup-To:" header set to alt.os.linux.slackware.]
On 2008-01-09, Mr. Usenet <spamtheftc@yahoo.com> wrote:
> Hi
>
> I'm running Slackware 12.0, kernel 2.6.21.5. I have a dvd and a cd
> drive. My problem is that the link /dev/cdrom intermittently points
> to /dev/hdd, i.e.:
>
> %~$ ls -l /dev/cdrom
> lrwxrwxrwx 1 root root 3 2008-01-08 07:13 /dev/cdrom -> hdd
>
> rather than /dev/hdc.
>
> This is after I created the file:
>
> /etc/udev/rules.d/10-local.rules
>
> which contains:
>
> KERNEL=="hdc", SYMLINK="cdrom"
>
> Before I created this file, it constantly pointed to /dev/hdd. Now,
> it
> seems to alternate daily between hdc and hdd. When I do:
>
> udevtest /sys/block/hdd
>
> I get:
>
> ....
>
> update_link: found '/block/hdc' for 'cdrom'
> update_link: compare priority of '/block/hdc' 0 > 0
> update_link: found '/block/hdd' for 'cdrom'
> update_link: compare (our own) priority of '/block/hdd' 0 >= 0
> update_link: 'cdrom' with target 'hdd' has the highest priority 0,
> create it
> ....
>
> which seems to say that there is still some file trying to push /dev/
> hdd as
> the link from /dev/cdrom. One other confusing thing is that the
> timestamp
> in:
>
> lrwxrwxrwx 1 root root 3 2008-01-08 07:13 /dev/cdrom -> hdd
>
> for the created link is 07:13, and the computer was not on at this
> time.
>
> So can anyone tell me how to make the link with /dev/hdc permanent?
> Thanks.


See /etc/udev/rules.d/75-optical-devices.rules
Edit the generated rules in there to make the links point where you
want them to point. Also remove your custom rule - it's not needed.
The conflict you were seeing is/was the result of your custom rule
in conjunction with the generated rules.

-RW

jayjwa <jayjwa@vdrl.ath.cx.invalid> wrote:
> IMO, dump udev. How many times does one really add devices to their system?

Every time you insert an USB stick? Every time you connect something else
by USB? IMHO udev is a good replacement for the old hotplug. Also fixed
devices like network cards are handled well. With udev it is easy to make
sure that a card with a special mac address always gets named eth1.

> udev takes something trivial, adds a bunch of config files, makes it
> more complex, and then fails to work. Progression, backwards.

For me it was rather easy to understand how to edit udev files. I have
also been able to edit some hald files, but I think that the hald files
are more messy.

regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc1(at)poolhem.se Examples of addresses which go to spammers:
root@localhost postmaster@localhost

On Jan 10, 1:47 pm, "Mr. Usenet" <spamthe...@yahoo.com> wrote:
> toshiro wrote:
> > On Jan 9, 1:46 pm, "Mr. Usenet" <spamthe...@yahoo.com> wrote:
>
> > ...
> > > So can anyone tell me how to make the link with /dev/hdc permanent?
> > > Thanks.
>
> > If you *always* want your cdrom to point to /dev/hdc AND you do not
> > need dynamic assignment of you cdrom device... then there is no need
> > to use udev for this
> > so remove *your* changes from /etc/udev/rules.d, and instead do the
> > following:
>
> > Make sure user.group of /dev/hdc is root.cdrom
> > (ls -l /dev/hdc = brw-rw---- 1 root cdrom 22, 64 2008-01-09 05:58 /dev/
> > hdc)
>
> > Make a symlink /dev/cdrom -> /dev/hdc
> > (ls -l /dev/cdrom = lrwxrwxrwx 1 root root 3 2008-01-09 05:58 /dev/
> > cdrom -> hdc)
>
> > In fstab uncomment the line (or add the line):
> > /dev/cdrom /mnt/cdrom iso9660 noauto,user,ro 0 0
>
> > This should do what you need.
>
> Thanks for the reply. I'm wondering though, if the above will work
> since
> the system was already set similar to what you have said. fstab has
> the
> lines you mention, and I get the following when I do:
>
> $ ls -l /dev/hdc
> brw-rw-rw- 1 root cdrom 22, 0 2008-01-10 01:08 /dev/hdc
> $ ls -l /dev/cdrom
> lrwxrwxrwx 1 root root 3 2008-01-10 01:08 /dev/cdrom -> hdc
>
> The only difference is the permissions on my /dev/hdc which is "brw-rw-
> rw-"
> rather than "brw-rw----". And if I remove rw from o, i.e.
>
> chmod o-rw /dev/hdc
>

Hang on you may have misunderstood - your hdc perms are correct,
they should be brw-rw-rw and the ownership should root:cdrom.
As a normal user you should belong to the cdrom group by default. If
not you can add yourself.

> I'm worried I won't be able to use the cdrom writer.
> I can remove the rules I added to make things almost exactly like
> before, but I think it will just mean that /dev/cdrom will
> permanently point to /dev/hdd which was my initial problem.

You want the cdrom to point to /dev/hdc right?
So make the symlink yourself as I stated earlier and udev will not
change it.

I had a similar problem when I first started using udev+hal+messagebus
with Slack12.
So I simply uncommented the cdrom line in fstab and made the following
link /dev/cdrom -> /dev/hdc (in my case for CD/RW), and it just worked
fine after that.
Programs like kplayer, k3b, xmms, etc work fine, also KDE (which auto
mounts
to /media/cdrom/.... work OK)

The advice of other people about editing udev rules is correct as
well, but my CD devices are
*screwed* into my desktop, laptop, whatever - I do not plug them in
and out at all. So why should I use udev to manage them. Things like
cameras & mem sticks are good candidates for udev but NOT an internal
DVD. For me using fstab and /dev/cdrom->/dev/hdc works fine.

It is your choice which way to go but try the fstab + symlink method,
it is trivial and
you can always rollback your changes in a minute.

And let us know the results. Good luck.

Thanks again for everyone's reply.


On Fri, 11 Jan 2008 07:39:56, toshiro wrote:
>You want the cdrom to point to /dev/hdc right?
>So make the symlink yourself as I stated earlier and udev will not
>change it.

I did make this link myself initially before I knew anything about
udev, but it reverted on the next boot. But not after I learned about
udev and made all the rules. So I just did this as root and will
see how it works.

>And let us know the results. Good luck.

Thanks, although if the trick was to make the symlink after
creating rules than before, then this isn't very intuitive.

On Thu, 10 Jan 2008 20:15:33, jayjwa wrote:
>IMO, dump udev. How many times does one really add devices to their system?
>udev takes something trivial, adds a bunch of config files, makes it
>more complex, and then fails to work. Progression, backwards.

I admit this is the way I feel too. As a user of Slackware, many
times
these attempts to automate configuration usually leads to frustration
for me, especially since I don't mind manually handling the mounting
of
hardware. I remember when setting up a printer first meant
configuring
"printcap", then they added "modules.conf", and now CUPS. Sound
started
with ISAPNP, then "sndconfig", then they added "modules.conf", and now
it's "alsaconf". Each time, hours of hard fought knowledge went out
the window as I struggled with the new system that often still had a
lot of kinks. I'm an 10+ year user of Linux, and if I get exasperated
by the changes, what will this mean to non-Unix newbies.

But I guess the point of the changes were so that new users wouldn't
have to struggle with configuration, and since every new version of a
distribution will end up using the new utilities, I've decided just to
go along.

On Fri, 11 Jan 2008 05:22:37, Robby Workman wrote:
>See /etc/udev/rules.d/75-optical-devices.rules
>Edit the generated rules in there to make the links point where you
>want them to point. Also remove your custom rule - it's not needed.
>The conflict you were seeing is/was the result of your custom rule
>in conjunction with the generated rules.

I've taken a look but I couldn't figure out what to do except maybe
comment out the line:

ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.1-ide-1:1",
SYMLINK+="cdrom"

I tried tracing this to /lib/udev/cdrom-symlinks.sh, but I can't see
anything about "hdd" or "hdc". My online reading of:

http://reactivated.net/writing_udev_rules.html

didn't help much either, since it seems they thought that
my custom rules would have been enough.

On Fri, 11 Jan 2008 08:27:35, Henrik Carlqvist wrote:
>Every time you insert an USB stick? Every time you connect something else
>by USB? IMHO udev is a good replacement for the old hotplug. Also fixed
>devices like network cards are handled well. With udev it is easy to make
>sure that a card with a special mac address always gets named eth1.

I admit, my USB flash drive gets detected pretty easily.

jayjwa wrote:
> Henrik Carlqvist <Henrik.Carlqvist@deadspam.com> writes:
>
>>> IMO, dump udev. How many times does one really add devices to their system?
>> Every time you insert an USB stick? Every time you connect something else
>> by USB? IMHO udev is a good replacement for the old hotplug. Also fixed
>> devices like network cards are handled well. With udev it is easy to make
>> sure that a card with a special mac address always gets named eth1.
>
> OK, I should've said this better: how many times does one initially
> add devices to their system? I don't have to re-make the device files
> every time I plug/unplug, for example, my USB flash drive, ACM modem,
> PSP/SanDisk. The device file is just a window to what's there (or
> not).

You point is that in your case, you have intentionally taken
something that was inherently designed to be pluggable and want
to make it static... and as mentioned, there are many things that
can be keyed off of to create persistent names.

>
> Actually, if udev removes and re-creates device files each and every
> time a device is pulled or plugged in, it's likely slower because the
> act of deletion and creation along with any processing of the program
> itself, takes time.

Sure. Obviously, since the device is inherently non-static, there
is a dynamic piece to it. And this CAN get in the way if the assumption
is made that the device is always present. You may well have to thwart
the system a bit and create a static device file (like the old days).
However, there are a lot of variables... so even this might not
work (floating buses).

>
> There seems to be two hotplugs floating around too. I see Linux
> systems where the users talk about editing files; this would be the
> script one. Then there's one with nothing to edit, which is the one I
> have and like.

???

I don't edit any files and my device hotplugs and mounts at the
same location everytime since the volume or device name is used
for the mountpoint.

Maybe you simply needs some kind of volume name set on the device (?).

>
>> For me it was rather easy to understand how to edit udev files. I have
>> also been able to edit some hald files, but I think that the hald files
>> are more messy.
>
> I'm sure it's possible, but with so many other config files and things
> to wrestle with, why make something that's simple and already works
> more differicult?
>

Uh... it didn't work. You "think" it worked because it happened to
work in your particular case. While it is true that most people
do define things only in the way that it relates to themselves, it's
probably more useful to create a definition that everyone can use.