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2. Procedure

Summary of Steps

Also, make sure you've read Section 1 and Section 1.2.

2.1. Creating the ISO Images

Choose (or create) a file system with the largest available disk space on it. Keep in mind that CD-ROM's can hold around 640MB of data, so if you want to share 8 full CD's on your network, you'll need 5.1GB of space available.

Login as root or "su" to root.


bash# df -h


Filesystem            Size  Used Avail Use% Mounted on
/dev/hda5             1.4G   82M  1.3G   6% /
/dev/hda1              15M  827k   14M   6% /boot
/dev/hda7             2.4G 1008M  1.3G  43% /usr
/dev/hda8            23.6G 11.7G 11.7G  50% /home


Here the /home filesystem has the most available space, so it is the most suitable filesystem to use for dumping the CD images to.


bash# cd /home
bash# mkdir image
bash# cd image

Now, copy the CD to an ISO image. You must know the device name of your CD-ROM drive (usually /dev/cdrom, it could be /dev/scd0 for SCSI CD-ROM's) I'll use the Mandrake distribution CD-ROM as an Example:


bash# dd if=/dev/cdrom of=mndrk81.iso

Note

The "if=" is the input file, the "of=" is the output file. You should see a message stating the number of records in and number of records out.

If you see i/o errors, they will most likely be due to the lead-in and lead-out runoutblocks on the CD. If the number of records in and number of records out do not match you may have a problem, otherwise the image will most likely be alright, but you can never know if the errors happened while reading the ISO part of the CD or not (due to dust or scratches on the CD).

Other utilities to read CD's exist, like readcd or sdd.

More information about making 1:1 copies of CD's exists in the [CD-Writing-HOWTO], see Section 1.3.

My thanks to Giblhauser Carl Michael for the runoutblock information.

2.2. Mounting the ISO Images

The next step is to mount the ISO image file. Let's create a directory under /mnt to place the mounted file.


bash# cd /mnt
bash# mkdir iso
bash# cd iso
bash# mkdir mndrk81

Now mount the ISO image file to this newly created directory


bash# mount -o loop,unhide -t iso9660 -r /home/image/mndrk81.iso /mnt/iso/mndrk81

Note

The "-o loop" means use the option that mounts a file as a block device. The unhide option shows hidden files. The "-t iso9660" means that the file is in the iso9660 CD-ROM format. The "-r" means to mount read-only.

Thanks to Amar Chaouche for pointing out the unhide option for the mount command.

Now you can:


bash# cd mndrk81
bash# ls -al

You should see a listing (ls) of the files and directories that are on the actual CD (only now they're inside the ISO image file, and that's what you're currently looking at!)

2.3. Mounting the Image upon System Restart

Now that we've manually mounted the image, and made sure it works, an entry needs to made in the /etc/fstab file so that the image is remounted on the next system startup. It's important to make the entry AFTER the entry for the parent filesystem, e.g. /home (I use vim, but emacs, joe, pico or jed will work just as well):


bash# vim /etc/fstab

After the line that looks like the following (or whichever filesystem you've placed your images):


/dev/hda8 /home ext2 defaults 1 2

Insert the following line with your text editor:


/home/image/mndrk81.iso /mnt/iso/mndrk81 iso9660 ro,loop,auto,unhide 0 0

2.4. Sharing it on a Windows Network using Samba

You'll need to have Samba installed and working to perform the next steps (that's outside the scope of this instruction, see Section 1.3). If it's not yet installed, consult your Linux distribution's instructions for installing the Samba package. Or you can visit the Samba website at http://us1.samba.org/samba/samba.html for installation instructions, binaries, and/or the source code.

To share your mounted CD's on a windows network, simply create a stanza in the /etc/smb.conf file similar to the following:


[cdimages]
  comment = All Shared CD Images
  path = /mnt/iso
  public = yes
  writable = no

This will share all the subdirectories under the /mnt/iso directory on the network. To mount the share to a local drive (in this case the I: drive), bring up an MS-DOS Prompt on the Windows machine and type the following:


C:\> net use I: \\yourlinuxmachine\cdimages

Each CD image will now appear as a subdirectory on the I: drive of your Windows machine.

To mount ONLY the Mandrake CD image to a drive letter (we'll use M:, the root drive of which, will correspond exactly to the CD as if it was just inserted in the CD-ROM drive), create the following stanza in the /etc/smb.conf file.


[mndrk81]
  comment = Mandrake Linux 8.1
  path = /mnt/iso/mndrk81
  public = yes
  writable = no

Then, at your MS-DOS Prompt, mount it with the following command:


C:\> net use m: \\yourlinuxmachine\mndrk81

Warning

The Samba smb.conf file stanzas presented here are simplified, and not secure. Many more options exist for a Samba share which limit who can mount the shares, control how user authentication is performed, and whether the share is even browseable through Network Neighborhood on the Windows machines.

2.5. Sharing the Images on a Unix network using NFS

Make sure that NFS is running and configured correctly on your Linux machine, then add the following to the /etc/exports file using your own preferred options:


# sample /etc/exports file
       /mnt/iso            (ro,insecure,nohide,all_squash)

Note

The nohide option will allow you to mount a parent directory, without explicitly mounting all exported subdirectories beneath it.

Now try running:


bash# exportfs -r

This should re-export everything in your /etc/exports file.

Now, when typing "showmount -e yourlinuxmachine" you should see that the /mnt/iso directory is included in the exports list.