CDfs v0.5c

What?

a'

[root@k6 /root]# mount -t iso9660 -o ro /dev/cdrom /mnt/cdrom

[root@k6 /root]# ls -l /mnt/cdrom
total 2
-r-xr-xr-x 1 root root 2 Aug 8 19:16 a
-r-xr-xr-x 1 root root 2 Aug 8 19:19 b

If you mount the CD with the cdfs file system, you get the two sessions as files:

[root@k6 /root]# mount -t cdfs -o ro /dev/cdrom /mnt/cdfs

[root@k6 /root]# ls -l /mnt/cdfs
total 33389
-r--r--r-- 1 ronsse ronsse 33503232 Aug 8 19:36 sessions_1-1.iso
-r--r--r-- 1 ronsse ronsse 34121728 Aug 8 1999 sessions_1-2.iso

These files can then be mounted loop back:

[root@k6 /root]# mount -t iso9660 -o loop /cdfs/sessions_1-1.iso /mnt/loop1

[root@k6 /root]# mount -t iso9660 -o loop /cdfs/sessions_1-2.iso /mnt/loop2

and the file a can be accessed in both sessions

[root@k6 /root]# ls -l /mnt/loop1
total 9889
-r-xr-xr-x 1 root root 10104236 Aug 8 17:34 a

[root@k6 /root]# ls -l /mnt/loop2
total 2
-r-xr-xr-x 1 root root 2 Aug 8 19:16 a
-r-xr-xr-x 1 root root 2 Aug 8 19:19 b

The file system also allows you to access data on faulty multi session disks, e.g. disk with multiple single sessions instead of a multi session (for instance created with mkisofs without the proper -C parameters).

Limitations

Download, compile & install

here

make

insmod cdfs.o

Usage

mount -t cdfs -o ro /dev/cdrom /mnt/cdfs

Check /proc/cdfs for information about the tracks. The exported files can be found under /mnt/cdfs and will have one of these names:

sessions1_?.iso: an ISO session. ISO sessions are exported in groups, e.g. if you have a disk with four images, you get

[root@k6 /root]# mount -t cdfs -o ro /dev/cdrom /mnt/cdfs

[root@k6 /root]# ls -l /mnt/cdfs
total 0
-r--r--r-- 1 ronsse ronsse 362471424 Mar 10 21:39 sessions_1-1.iso
-r--r--r-- 1 ronsse ronsse 518234112 Apr 10 01:11 sessions_1-2.iso
-r--r--r-- 1 ronsse ronsse 638572544 Jun 19 22:33 sessions_1-3.iso
-r--r--r-- 1 ronsse ronsse 680714240 Jul 21 01:35 sessions_1-4.iso

The first file contains the first session, the second file contains sessions 1 & 2, the 3 contains sessions 1, 2 & 3 and the last file contains all the sessions. You can mount all the files/sessions at the same time:

[root@k6 /root]# mount -o loop /cdfs/sessions_1-1.iso /mnt/loop1
[root@k6 /root]# mount -o loop /cdfs/sessions_1-2.iso /mnt/loop2
[root@k6 /root]# mount -o loop /cdfs/sessions_1-3.iso /mnt/loop3
[root@k6 /root]# mount -o loop /cdfs/sessions_1-4.iso /mnt/loop4

session-?.iso: a single session ISO image. Use the 'single' option when mounting to access all sessions on a CD as single session images, e.g.:

[root@k6 /root]# mount -t cdfs -o ro,single /dev/cdrom /mnt/cdfs

boot.image: a boot image. Use the file command to check the file system on the boot disk and mount it loop back. E.g. (WIN98):

[root@k6 /root]# mount -t cdfs -o ro /dev/cdrom /mnt/cdfs

[root@k6 /root]# ls -l /mnt/cdfs
total 0
-r--r--r-- 1 ronsse ronsse 1474560 Jan 1 1970 boot.image
-r--r--r-- 1 ronsse ronsse 654815232 Nov 24 1998 sessions_1-1.iso

[root@k6 /root]# file /mnt/cdfs/boot.image
/mnt/cdfs/boot.image: x86 boot sector, system )+3EjIHC, FAT (12 bit) unlabeled, 2880 sectors

[root@k6 /root]# mount -t vfat -o loop /mnt/cdfs/boot.image /mnt/loop1

[root@k6 /root]# head /mnt/loop1/autoexec.bat
@ECHO OFF
set EXPAND=YES
SET DIRCMD=/O:N
cls
set temp=c:\
set tmp=c:\
path=a:\

IF "%config%"=="NOCD" GOTO QUIT
LH MSCDEX.EXE /D:oemcd001 /L:D

apple.hfs: an Apple Hierarchical File System. You can mount it loop back with the hfs file system. Example: a CD with one data track containing both an ISO and a HFS file system:

[root@k6 /root]# mount -t cdfs -o ro /dev/cdrom /mnt/cdfs

[root@k6 /root]# ls -al /mnt/cdfs
total 15666
dr-xr-xr-x 2 ronsse ronsse 1234 Aug 14 18:46 .
drwxr-xr-x 12 root root 1024 Jul 24 22:56 ..
-r--r--r-- 1 ronsse ronsse 16008192 Jan 1 1970 apple.hfs
-r--r--r-- 1 ronsse ronsse 61360128 Apr 17 06:18 sessions_1-1.iso

[root@k6 /root]# mount -t iso9660 -o loop,ro /mnt/cdfs/sessions_1-1.iso /mnt/loop1

[root@k6 /root]# mount -t hfs -o loop,ro /mnt/cdfs/apple.hfs /mnt/loop2

[root@k6 /root]# ls -a /mnt/loop1
. .. autorun.inf files jpg1024 jpg1152 jpg1280 jpg640 jpg800 setup.exe

[root@k6 /root]# ls -a /mnt/loop2
. .. .finderinfo .resource .rootinfo AppleShare PDS Desktop DB Desktop DF M&T ScreenSaver M&T ScreenSaver Data OpenFolderListDF:0d Trash

videocd-?.mpeg: a VideoCD track. Use your favourite player to view the contents (mtv[p], plaympeg, gtv, ZZplayer).

track-?.wav: an audio file. The file starts with a WAV-header and can be copied or played (by copying it to the audio device) , e.g.

[root@k6 /root]# mount -t cdfs -o ro /dev/cdrom /mnt/cdfs
[root@k6 /]# ls -l /mnt/cdfs
total 0
-r--r--r-- 1 ronsse ronsse 42973392 Aug 8 18:01 track-1.wav
-r--r--r-- 1 ronsse ronsse 65164512 Aug 8 18:01 track-2.wav
-r--r--r-- 1 ronsse ronsse 71743056 Aug 8 18:01 track-3.wav
-r--r--r-- 1 ronsse ronsse 66940272 Aug 8 18:01 track-4.wav
[root@k6 /]# sox /mnt/cdfs/track-1.wav -t ossdsp /dev/dsp
track-?.raw: a raw audio track without the WAV header.
Note that audio tracks are `exported' by cdfs because they are on the CD. However, cdfs will make no attempt to correct reading errors while reading from scratched disks, to solve misalignment, frame jitter, loss of streaming, etc. You should use cdparanoia or cdda2wav if you encounter these problems.

Related work:

for audio tracks only:

audiofs for Linux
CDFS.VXD for Win
cdda-fs for BeOS

for VideoCD only:

vcdfs, xreadvcd and vcdread for Linux

History

For kernel 2.2.X:

v0.1 (08/21/99): Original Release.
v0.2 (10/24/99): Added support for detecting the type of boot image.
v0.2b (11/05/99): Solved problem with versioned symbols (thanks to Bodo Bellut).
v0.3 (01/06/00): Audio cache is now dynamically allocated. Removed 1/75 seconds of silence from the start of each audio track. Better memory management. Detects more boot images. Changed numbering of audio tracks.
v0.3b (01/11/00): Solved problems with systems with multiple CD drives (cache problems).
v0.3c (01/17/00): Several bugfixes.

For kernel 2.4.X:

v0.4 (07/27/00) for 2.4.X: Added a kernel thread 'kcdfsd' for asynchronuous I/O and support for VideoCD (thanks to Chih-Chung Chang). Karaoke CDs should also work. Uses address_space_operations for all block sizes. Simplified root.c. Support for bigendian CPUs.
v0.41 (09/12/00) adapted for 2.4.0-test8.
v0.42 (01/25/01) support for multiple boot images (thanks to Olaf Lösken).
v0.5 (02/21/01) usage of ./configure (thanks to Moritz Barsnick.
v0.5a (02/27/01)
v0.5b (12/27/01) added support for raw tracks (e.g. avi files written as audio tracks; thanks to Attila Karpati). /proc/cdfs now shows the discid for audio CDs. Added kernel patch for compiling cdfs as part of the kernel instead of a stand alone module (thanks to Jan F. Chadima).
v0.5c (04/07/02) bug fixes

Author

Michiel Ronsse

10/24/99