My system:
hda-Primary/Master-20G ide
hdb-CD-R-Primary/Slave
hdc-DVD-Secondary/Master

Are the following 2 statements correct?
Since hdb invokes scsi emulation hdb is also known as sr0 & sr0 is also known as scd0 & scd0 is also known as sda. The same is true of hdc=sr1=scd1=sdb. hmmmm....Why so many references to the same drive? What tells me to use /sr0 instead of /scd0 for example?.

Maybe I don't fully understand what fstab does; each line has to have a device name of course-but which device name, does the mount point go there too?-first or second? What about symlinks? Are there any hard and fast rules for fstab. I'm missing something easy here.

I don't seem to relate well to info pages and man pages. Once I understand what I'm doing I can go there for reference but to learn how to use something...... I guess I prefer visual representations. Anybody seen a chart/diagram for symlinks & devices & etc.?

I'd shore 'preciate it could sumbuddy dumb it down for me! All the other kids are compiling kernels and I can't get past this!!

ide-scsi requires a kernel parameter (usually invoked by lilo or grub) such as 'hdb=ide-scsi'. 'ide-scsi' is required to let your cd recording software talk to your CD-R/W drives. Loading the module ide-scsi will not automatically make all IDE devices SCSI-ish and I've never used it for a plain old hard disk. Not even sure if it's a good idea to do so.

'fstab' tells the kernel where to mount the devices and reads like this (in this order) block device, mount point, filesystem type, mount options, dump, and pass (the latter two items are used for dump and fsck order - see the man pages 'man fstab' for more info).

The links in the /dev directory seem odd af first but are actaully quite handy when things change on your system. Say for example you have a cdrom drive on /dev/hdc. You tell /etc/fstab and all your software that uses the cdrom to look for it at /dev/hdc and everything works fine. But when you make a change in your system, say moving your cdrom to /dev/hdd, all applications that use the cdrom (and your /etc/fstab) will have to be told where you moved it to. But if you were using a link to your cdrom drive (/dev/cdrom -> /dev/hdc) and you told you software to use /dev/cdrom, all you need to change is the link /dev/cdrom -> /dev/hdd. The same holds true for other devices, like a mouse or a modem. Using /dev/mouse means that if you were to buy a flashy new cordless optical vibrating USB chromed mouse you would only need to change the link /dev/mouse to point to the device under the /dev filesystem.

Thanks mcleodnine for clarifying a few things for me. I'm getting closer.
My cdrom is scd0 and my dvd is scd1. If I plug these variables into xine everything works fine so I am certain that scd0 & scd1 are correct but as you stated:
With that in mind I have then created these links:

ln -s scd0 /dev/cdrom
ln -s scd1 /dev/dvd

and the following shows that I did in fact create the links:

ls -a /dev/cdrom
. . . scd0
ls -a /dev/dvd
. . . scd1

--I'm not sure what the '. . .' means.

Here are the corresponding lines from fstab
/dev/cdrom /mnt/cdrom iso9660defaults,ro,user,noexec,noauto 0 0
/dev/dvd /mnt/dvd iso9660 defaults,ro,user,noexec,noauto 0 0

If I put /dev/cdrom & /dev/dvd into xine it won't work.
If I try to mount /dev/cdrom or /dev/dvd with data disks in them I get the 'not a valid block device' error. I think it's my fstab that's incorrect but I don't know how to fix it. Thanks again for any help.

edit - maybe this is of some help
root@cromag:# ls -al /dev/cdrom
total 36
drwxr-xr-x 2 root root 4096 Mar 22 20:31 .
drwxr-xr-x 12 root root 32768 Mar 22 20:08 ..
lrwxrwxrwx 1 root root 4 Mar 22 20:31 scd0 -> scd0
root@cromag:# ls -al /dev/dvd
total 36
drwxr-xr-x 2 root root 4096 Mar 22 20:31 .
drwxr-xr-x 12 root root 32768 Mar 22 20:08 ..
lrwxrwxrwx 1 root root 4 Mar 22 20:31 scd1 -> scd1

ln -s /dev/scd0 /dev/cdrom

OK I linked them the same way you did and here I am:

root@cromag:~# ls -al /dev/scd0
brw-rw---- 1 root lpadmin 11, 0 May 31 2001 /dev/scd0
root@cromag:~# ls -al /dev/cdrom
total 36
drwxr-xr-x 2 root root 4096 Mar 23 07:06 .
drwxr-xr-x 12 root root 32768 Mar 22 20:08 ..
lrwxrwxrwx 1 root root 9 Mar 23 07:06 scd0 -> /dev/scd0
root@cromag:~# ls -al /dev/scd1
brw-rw---- 1 root lpadmin 11, 1 May 31 2001 /dev/scd1
root@cromag:~# ls -al /dev/dvd
total 36
drwxr-xr-x 2 root root 4096 Mar 23 07:06 .
drwxr-xr-x 12 root root 32768 Mar 22 20:08 ..
lrwxrwxrwx 1 root root 9 Mar 23 07:06 scd1 -> /dev/scd1

Still not right though is it?

thanks again mcleodnine

yeah that looks right.... do they work when you use the actual /dev/scd0 instead of /dev/cdrom?

Correct- xine works if I use /dev/scd0 & /dev/scd1. Xine will not work with /dev/cdrom or /dev/dvd
With data disks inserted I cannot mount either drive like this:.

root@cromag:/home/glenn# mount /dev/dvd /mnt/dvd
mount: /dev/dvd is not a block device
root@cromag:/home/glenn# mount /dev/cdrom /mnt/cdrom
mount: /dev/cdrom is not a block device
root@cromag:/home/glenn#

This doesn't work either:
mount -t auto /dev/dvd /mnt/dvd

But I can mount them like this:

root@cromag:~# mount /dev/scd1 /mnt/dvd
mount: block device /dev/scd1 is write-protected, mounting read-only

Here are fstab lines
/dev/cdrom /mnt/cdrom iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/dvd /mnt/dvd iso9660 defaults,ro,user,noexec,noauto

This doesn't seem right to me:
root@cromag:~# ls -al /dev/cdrom
total 36
drwxr-xr-x 2 root root 4096 Mar 23 07:06 .<-is this normal?
drwxr-xr-x 12 root root 32768 Mar 23 09:20 ..<-is this normal?
lrwxrwxrwx 1 root root 9 Mar 23 07:06 scd0 -> /dev/scd0


Thank you for your help.

ok... 'rm /dev/dvd' and 'rm /dev/cdrom'

then try...

'ln -s /dev/scd0 /dev/cdrom'
'ln -s /dev/scd1 /dev/dvd'

eureka!
I removed all the links, relinked and now everything seems to be hunky -dory. Not sure what I had jammed up but removing the links seemed to do the trick. Thanks mcleodnine for your help- mucho appreciado hombre'

oops- almost forgot, I also removed the cdrom & dvd directories, recreated them and then relinked.