Adding a second cdrom
 

I have a dvd and a cdrw in my computer. The dvd was set up automatically by slackware 9.1 and the cdrw was not. Now I know I need to edit /etc/fstab so that I can be able to mount it, but i'm lost when it comes to the /dev/somedevice. I looked in /dev and don't see my cdrw listed under cdrom2 or anything like that. What do I need to do?

how are your devices installed? (i.e. master, slave, etc)
linux name devices such as:

hda, primary master
hdb primary slave
hdc, secondary master
hdd, secundary slave

so it's a matter to figure out which one's the cd rom, and find it in /dev/hdx in order to edit fstab

Hope this help :)

See if you have a /dev/cdrom. If you have, delete it and then create it again with a link to /dev/sr0 (providing that is your correct device, there should be a message in dmesg about it). If this doesn't work its most likely you don't have the magic line in /etc/lilo.conf which is

append="hdd=ide-scsi"

providing again that hdd is the correct device. If you have your DVD in the first slot on the secondary IDE and your CD-RW in the second as I think most people would be set up, the above should work.

I don't know if you have one or 2 hard drives in your system, but my recommendation would be to not put both the CD and DVD on the same ribbon cable. Because both are removable media devices, it can screw things up during boot if both are empty (at least that has been my experience).

I would recomend you set things up this way:

Primary Master = main hard drive
Primary Slave = DVD
Secondary Master = CD
Secondary Slave = second hard drive (if it exists)

-- J.W.

Well, I've tried a couple things. First I tried linking to cdrom2 to hdd, that didn't work. Then I tried linking cdrom2 to sr0 with the append statement and that didn't work. Weird thing is, on both, when i accessed cdrom or cdrom2 i would get the contents of my dvd (cdrom). I'm confused now.

J.W. - I've never had a problem with having a both on the same strip in linux before (or windows). Thanks for the suggestion though.

Any other ideas?

Protex, showing us your fstab would help immensely.

JW, setting a CD/DVD/Non-HDD device as master is highly unrecommended. This is because those drives are WAAAAYYY slower than hard disks. And this will degrade the performance of the slave especially if it is a HDD.

However, your suggestion on separating CD/DVD and CD-RW on different IDE cables is recommended because having them on the same IDE bus will cause bottleneck if you want to do on-the-fly CD copying and may result in coasters (although rare nowadays, because of technologies like burn-proof, etc).

Azmeen - well I agree with you partially. On a system with one drive, a CD, and a DVD, either the CD or DVD has to be jumpered as the Master on IDE-2, right? Regarding possible performance degradation, Yes, your point makes sense but at least for me it has not been an issue. (The layout suggestion I posted is how I've got my system set up, and so far it has been working pretty well.) Admittedly I do not put a significant load on my 2nd HD, perhaps if I did I may be coaxed into re-evaluating my layout. As I indicated before, at least back in the days when I was trying to configure my box, I ran into trouble if I had both HD's on the same cable and a CD and CD-RW both on the other cable. Arranging them as I mentioned avoided all problems, at least for me. -- J.W.

JW, maybe your problem was due to the limited capabilities of systems at that time :scratch:

However, speaking from experience (sysadmin of three years++ multiple OS/hardware/platforms)... no, optical media does not necessarily have to be a master of whatever IDE channel. In fact, like I stated earlier, it's not recommended, of course you still can do it, it'll just slow down the system if you perform operations off the hard disk while doing something on the CD as well.

You'll have to benchmark this yourself to see the results "live" because I agree that you have to see it in order to believe it.

Something simple would be copying a 100MB file from one HD to another while playing a music CD... or something along those lines... :)

Here is my fstab:

/dev/hdb1 swap swap defaults 0 0
/dev/hdb5 / reiserfs defaults 1 1
/dev/cdrom /mnt/cdrom iso9660 noauto,users,ro 0 0
/dev/cdrom2 /mnt/cdrom2 iso9660 noauto,users,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,users 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
proc /proc proc defaults 0 0


cdrom (dvd) points to hdc
cdrom2 (cdrw) points to sr0

Protex,

That looks just right to me... I assume you added the append line to your lilo.conf, did you run /sbin/lilo as root after that? Any error messages?

Azmeen - well, shoot, I'd like to think that I know more now than I did back then, and your suggestion certainly is easy enough to experiment with, so this weekend I'll give it a try. If it speeds things up, as it very well may do, heck, I owe you one.

Protex- I'll echo Azmeen's comments about rerunning lilo. One other question, from the Obvious Dept: I assume you've verified that all necessary connections, cables, and the like are seated properly and secure. I have no doubt that they are, but hey, I once spent about 3 hours trying to completely overhaul my entire suite of audio software, until I discovered that the problem was that the the speaker cable was no longer plugged into the sound card (apparently due to the GF's overly curious cat). Oops. Oh well live and learn -- J.W.

The cdrw isn't new, it's been in the system for quite some time so it can't be that a cable is loose (i had to burn the iso some how). It just wasn't setup by Slackware. It did work fine under mandrake 9.0, 9.1, and 9.2 rc2 so i know it is possible.

I did run lilo after I added the append, so i'm ruling that out too.

Cdrom2 points to sr0 so is it possible that that isn't my cdrw?
The reason I ask this is because both cdrom and cdrom2 access my dvd at this point.

I gathered that from what you posted that your cdrom and cdrom2 symlinks are somehow pointing to the same device. Can you state where are they pointing to exactly?

Another thing, how is your IDE devices set up? Something like this listing:
Primary Master: Hard Disk
Primary Slave: DVD-ROM
Secondary Master: Burner
Secondary Slave: none

...will help immensely.

Primary Master: Hard drive 1
Primary Slave: Hard Drive 2
Secondary Master: DVD
Secondary Slave: CDRW

File: `/dev/cdrom' -> `hdc'
Size: 3 Blocks: 1 IO Block: 4096 symbolic link
Device: 345h/837d Inode: 170561 Links: 1
Access: (0777/lrwxrwxrwx) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2003-10-05 21:27:13.000000000 -0400
Modify: 2003-10-03 19:47:37.000000000 -0400
Change: 2003-10-03 19:47:37.000000000 -0400

File: `/dev/cdrom2' -> `sr0'
Size: 3 Blocks: 1 IO Block: 4096 symbolic link
Device: 345h/837d Inode: 170639 Links: 1
Access: (0777/lrwxrwxrwx) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2003-10-05 21:27:13.000000000 -0400
Modify: 2003-10-03 20:33:46.000000000 -0400
Change: 2003-10-03 20:33:46.000000000 -0400

This may sound weird but, have you tried linking /dev/cdrom2 to sr1?