1.1. Intended Audience

This HOWTO is specifically directed toward System Administrators and uses Linux for the examples. It should work with other flavors of Unix provided that they have a loop device or a method of mounting a CD image file within the directory tree as a block device using the iso9660 file system.

1.2. Things You'll Need

The commands and utilities needed to setup your own CD Server are already included in most (if not all) Linux distributions.

• Linux Distribution (This HOWTO uses Linux-Mandrake for the examples)

• dd - Converts and copies a file (a standard Unix command)

• mount - Mounts and Unmounts filesystems (a standard Unix command)

• Samba - A Windows SMB/CIFS fileserver for Unix

• NFS (optional) - Network File System (usually included in Linux distributions)

1.3. Suggested Reading

Using Samba by: Robert Eckstein, David Collier-Brown, Peter Kelly 1st Edition November 1999, O'Reilly and Associates, Inc. ISBN 1-56592-449-5,

1.4. Copyright

CDServer-HOWTO, Copyright (c) 2000, Randolph Tata, All Rights Reserved

Please freely copy and distribute (sell or give away) this document in any format. It's requested that corrections and/or comments be fowarded to the document maintainer (Randolph Tata). You may create a derivative work and distribute it provided that you:

• Send your derivative work (in the most suitable format such as sgml) to the LDP (Linux Documentation Project) or the like for posting on the Internet. If not the LDP, then let the LDP know where it is available.

• License the derivative work with this same license or use GPL. Include a copyright notice and at least a pointer to the license used.

• Give due credit to previous authors and major contributors.

If you're considering making a derived work other than a translation, it's requested that you discuss your plans with the current maintainer.

1.5. Disclaimer

Use the information in this document at your own risk. I disavow any potential liability for the contents of this document. Use of the concepts, examples, and/or other content of this document is entirely at your own risk.

All copyrights are owned by their owners, unless specifically noted otherwise. Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark.

Naming of particular products or brands should not be seen as endorsements.

You are strongly recommended to make a backup of your system before major installation and should make backups at regular intervals.

1.6. News

This is the first sgml release (version 1.00). SGML source for this document is available. Any additions/changes should be made to the sgml source, not derivative formats.

This documents home page is at the Open CD Server Project site page in case you need the latest version, or there is a problem with the page format you are viewing.

If you have the capacity it would be nice to make the CDServer-HOWTO available in a number of formats and languages.

1.7. Credits

In this version I have the pleasure of acknowledging

Mark F. Komarinski markk (at) linuxdoc.org LDP Author Guide Jorge Godoy godoy (at) metalab.unc.edu LDP Author Guide David C. Merrill dcmerrill (at) mindspring.com LDP Author Guide Stein Gjoen sgjoen (at) nyx.net HOWTO-Template Gregory Leblanc gleblanc (at) cu-portland.edu HOWTO-Template Greg Ferguson gferg (at) sgi.com HOWTO-Template

1.8. Translations

No Translations yet.

Any comments or suggestions can be mailed to my email address at Talcon Information Systems: <randy@talcon.com>.

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=mndrk71.iso

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 (hopefully with no i/o errors).

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 mndrk71

Now mount the ISO image file to this newly created directory

bash# mount -o loop -t iso9660 -r /home/image/mndrk71.iso /mnt/iso/mndrk71

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

Now you can:

bash# cd mndrk71 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/mndrk71.iso /mnt/iso/mndrk71 iso9660 ro,loop,auto 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). 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.

[mndrk71] comment = Mandrake Linux 7.1 path = /mnt/iso/mndrk71 public = yes writable = no

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

C:\> net use m: \\yourlinuxmachine\mndrk71

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,all_squash)

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

3.1. Tweaking the Kernel

To increase the number of loop devices supported by the kernel, you'll need to edit the /usr/src/linux/drivers/block/loop.c file.

If you find that the kernel sources are not installed on your machine, you'll need to consult your Linux Distribution's documentation on how to install them (the Kernel Sources come with all distributions - it's part of the GPL licensing).

Change the number in the following line to however many loop devices you'll need.

#define MAX_LOOP 16

Compile the new kernel or module as the case may be. If you need some help getting started with this, read /usr/src/linux/README.

3.2. Creating the Loop Devices in /dev

The mknod command creates the devices in /dev. The loop devices have a major number of "7", and the minor numbers begin at "0". If your MAX_LOOP was defined as 8 in /usr/src/linux/drivers/block/loop.c, you should have loop0 thru loop7 in /dev. To create the /dev/loop8 device, use the following command (subsitute the appropriate number for the "8" in the example below).

mknod -m660 /dev/loop8 b 7 8

Check Owner/Group & Permissions on the new file. You can change the owner and group with the following command:

chown root.disk /dev/loop8

You can change the permissions using the following command:

chmod 666 /dev/loop8