README

EFSMOD - Loadable Filesystem Module for Linux
=============================================


WHAT IT DOES ?
--------------
The efs.o is a loadable module for the Linux kernel.
It adds a new (read-only) filesystem called efs, 
which allows you to mount efs-CDROMs on your Linux box.
The EFS (extended filesystem) was developed by 
Silicon Graphics(TM) and is used for all storage devices
and so also for their software distribution CDROMs.


WHY ?
-----
If you have a Network with some SGIs connected to it,
you can now use every Linux box (with CDROM) as an 
installation server.


REQUIREMENTS
------------
- Linux > 1.3.71
- The driver of your CDROM must be able to operate with 512 Byte blocks!


INSTALLATION
------------
The installation is very simple:

0) Before starting, look if you have a working "module-environment" installed
   for Linux. If not, install one before proceeding!
1) Just untar and unzip the archive 
2) CD to this directory and type 'make' and the module 'efs.o' will be compiled
3) Copy efs.o to a place were you keep your Linux modules


MANUALLY MOUNT A CD
-------------------
1) su to become root
2) Install the module efs.o:

	/sbin/insmod /your_module_path/efs

   Now the module is installed and the filesystem is registred

3) Insert an EFS CD in your CDROM
4) Create an empty for use as a mount point:

	mkdir /mount_dir

5) Mount the filesystem  using:

	mount -r -t efs /dev/cdrom_dev /mount_dir

   where cdrom_dev is your CDROM-device (e.g. sr0,mcd...)

5) Add you mount_dir to /etc/exports if you want export the CDROM to the net:

	# /etc/exports
	...
	/mount_dir (ro)
   
6) For later use I suggest to add a mount entry in fstab to ease handling:

	# /etc/fstab
	...
	/mount_dir efs ro,noauto,user

   But don't forget to install the module before mounting!

7) Enjoy!


	--- WARNING ---

	The filesystem is still a <1.0 version!
	In the worst case it may crash your system
	(but I don't hope so!). So,
	USE IT AT YOUR OWN RISK!

	Also look in your kernel log to find efs related messages. 



MANUALLY UNMOUNT A CD
---------------------
1) su to become root
2) Unmount:
	umount /mountdir

3) Remove the module:
	/sbin/rmmod efs


LIMITATIONS
-----------
- The fs is read-only
- It's only tested with CDROMs (no harddisk,..)
- Tested only with the following CDs:
	IRIX(TM) 5.3 for Indy
	InPerson Desktop Conferencing 1.1
	IndiZone 2
	European Language Module 1.3
  (but it should work with any other CD, too!)


HISTORY
-------
<0.5 
	* a lot of internal hackish versions
0.5 - Feb96  
	* first public release
	* mainly the version developed a year ago
	* some simply code cleanup for you, the public!
0.6 - May96
	* in heavy parts rewritten, to support the new kernels (1.3.x)
	* the new kernel driver concept simplified the whole code
	* new storage method for the extends of a file (All direct
	  extends are stored in the inode. On an indirect inode 12 of all
	  extends are stored in the inode.)
	  -> HUGE speed gain for all files/dirs!


COPYRIGHT
---------
The whole archive (including all the source) is copyrighted by
Christian Vogelgsang under the GNU Public License Version 2.
Parts of the code are heavily based on Linus' Torvalds Minix FS
for Linux and so I state the following:

  EFS Filesystem		Copyright by Christian Vogelgsang
	based on
  Minix Filesystem: 		Copyright by Linus Torvalds


THE FAMOUS LAST WORDS
---------------------
If you have suggestions, bug reports or 
other interesting information about efs
just mail me!

Have Fun!

Christian Vogelgsang, cnvogelg@cip.informatik.uni-erlangen.de
 
