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Questions and Answers about Hard Drives and Linux

 How can I mount a HD on the cdrom cable?

Operating under the assumption you are talking about IDE, first, you need to know which controller it's on, and whether it's master or slave.  On the primary controller, master is /dev/hda and slave is /dev/hdb  On the secondary controller, master is /dev/hdc and slave is /dev/hdd

Next, you need to fdisk the new disk::

 fdisk /dev/hdc

Then, you have to create a filesystem on the new partition(s) mke2fs will create an ext2 filesystem. If you want to create ext3 partitions, the command is::

 mke2fs -j -L /somelabel 

where somelabel is the name of a mountpoint. The -L argument puts a drive label on the partition.

Then you can mount the disk::

  mount -t ext3 /dev/hdc1 /somelabel

If you want to make the partition mount every time you boot add an entry to your /etc/fstab::

  LABEL/somelabel  /somelabel ext3 defaults  1 2

see also "What's a good HD for Linux OS":LinuxHD