topic Re: CDRom device path in Operating System - Linux

CDRom device path

O'lnes — Fri, 20 Sep 2002 07:44:08 GMT

How to check what is the device path of CDRom? Thanks.

Re: CDRom device path

Dirk Wiedemann — Fri, 20 Sep 2002 08:01:30 GMT

What kind of computer?
What operating system?

Re: CDRom device path

O'lnes — Fri, 20 Sep 2002 08:11:30 GMT

The OS is Redhat 7.3

Re: CDRom device path

Donald Kok — Fri, 20 Sep 2002 08:14:57 GMT

you can read it in /etc/fstab.

Re: CDRom device path

Donald Kok — Fri, 20 Sep 2002 08:26:12 GMT

Also look at /etc/sysconfig/hwconf

Re: CDRom device path

I_M — Fri, 20 Sep 2002 08:42:31 GMT

Hi

I guess your CD-ROM is on either
IDE / SCSI or USB.

# dmesg | grep hd

# dmesg | greo sd

I'm not familiar with USB connection device.

Good luck

Re: CDRom device path

O'lnes — Fri, 20 Sep 2002 08:44:53 GMT

how about the checking of other device eg. harddisk, i use 'ioscan' in UNIX , how can check it in linux? Thanks.

Re: CDRom device path

Michael Kelly_5 — Wed, 25 Sep 2002 15:59:18 GMT

In linux, the device paths for hard disks are as follows (assuming that you don't have devfs):
IDE Disks
/dev/hda = Primary Master
/dev/hdb = Primary Slave
/dev/hdc = Secondary Master
/dev/hdd = Secondary Slave

Each disk can have up to 63 partitions and the first partition on the PM is /dev/hda1, the second partition is /dev/hda2 etc.

CDROMs don't have partitions on them so if your CDROM is the SM then you access it via /dev/hdc
e.g. mount -t iso9660 /dev/hdc /cdrom

SCSI disks are different. linux assigns the paths /dev/sda, /dev/sdb etc. in the order in which it finds the disks.
/dev/sda will be the lowest LUN on the first controller found, /dev/sdb will be the next lowest LUN on the first controller OR the lowest LUN on the second controller found etc.
SCSI disks can have up to 15 partitions so the first partition on the first disk is /dev/sda1 etc.
If you don't change the SCSI configuration then the order will be the same everytime linux boots. However if you add/remove a disk then the mapping will be different.

AS with IDE disks you refer to a SCSI CDROM via the whole disk path e.g. /dev/sdb

hth.