CD-Writing mini-HOWTO Winfried Tr�mper <winni@xpilot.org>

CD-Writing mini-HOWTO Winfried Tr�mper <[email protected]>
--------------------- Version 1.8 18 Mar 1997

I (Winfried Tr�mper) DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
DOCUMENT, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A CERTAIN PURPOSE; IN NO EVENT SHALL I BE LIABLE FOR ANY
SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
CONNECTION WITH THE USE OF THIS DOCUMENT.

Short: read and use at your own risk.

1. Introduction

My first experience with CD Writers was guided by the
"CD Writer mini-HOWTO" by Matt Cutts <[email protected]>.
Thanks Matt!

Although my intention was only to upgrade his document, I
rewrote it from the scratch after I realized how much changed
since 1994.

1.1. Suggested readings

The "Linux CD-ROM HOWTO" explains everything one should know
about CD-ROM drives under Linux.
As a supplement, you may want to take a look at the
"Linux SCSI HOWTO" and the "Linux Kernel HOWTO".

1.2. Terminology ... lasers at maximum ... fire!

"CD-ROM" stands for "Compact Disc Read Only Memory", a storage
medium utilizing an optical laser to sense microscopic pits on
a silver shimmering disk. (The silver shimmering comes from an
aluminized layer which is the carrier.) The pits represent the
bits of the information (in some way) and are so petite that
some billions of them fit on the disc. Thus a CD is a
mass-storage medium.

The Term "CD-R" is a short form of "CD-ROM recordable" and refers
to a CD that doesn't have those "microscopic pits" on it's
surface ... thus it's empty.
Instead of the aluminium layer (silver) it has a special film
(colored) into which "microscopic pits" can be burned in. This is
done by giving the laser which normally only senses the pits a
little bit more power so he burns the pits. This action can only
be taken _once_ on a CD-R.

This mini-HOWTO deals with the task of writing such a CD-R.
Welcome on board, captain.

1.3. Supported CD-Writers

"Linux" supports CD-writers of the following manufacturers

Philips, IMS, Kodak, Yamaha, Hewlett-Packard

or compatibles ...

If your hardware isn't supported you can still use Linux
to create an image of the later CD but then you have to use
DOS-Software to write the image to the CD-R. [You may wish to
do so because most DOS-software cannot deal with long
filenames available in Linux.]
In this case you can skip all hardware-related sections (those
about "generic SCSI devices" and "cdwrite").

1.4. Supported "features"

Currently the software for burning CDs under Linux does
support the following main features:

* RockRidge Extensions
* "Multisession" CDs and
* "El Torito" (bootable) CDs.

1.5. Mailinglists

If you want to join the development team (with the intention
to actively _help_ them), send e-mail to

[email protected]

and put the command "subscribe" in body of the message.

2. Prepare your Linux-box for writing CD-ROMs

2.1. Set up the hardware

(a) Shut down your computer, switch it off and hook CD writer to the
SCSI-bus. Please note that CD-writers require a SCSI-controller,
the standard EIDE-Interface of your PC has no ability to drive
those writers.

(b) Make sure the SCSI-bus is properly terminated and choose a free
SCSI-ID for the writer. Look at the Linux SCSI-HOWTO if you're
not sure. If you're completly clueless, ask an expert.

(c) Switch the power on again and check the messages that the BIOS of
the SCSI-controller prints immediatly after switching the power
on.
If it doesn't recognize you writer, go back to step (b).
You should see a message like

[missing picture; has anyone a screenshot of it?]

2.2. A note on writing CDs under Linux

In contrast to other rumors, the Linux-kernel does _not_
require a patch in order to write to CDs. Although the
file "drivers/scsi/scsi.c" from the kernel-sources
contains the lines

case TYPE_WORM:
case TYPE_ROM:
SDpnt->writeable = 0;

this does only mean that that CDs and WORMs are not writeable
through the standard-devices "/dev/sda"-"/dev/sdh" which is ok.

Instead of using these devices the writing of CDs is done
through the so called "generic SCSI-devices" which permit
nearly everything - even writing to CDs.

2.3. Create "generic devices"

The Linux SCSI-HOWTO says about generic SCSI-devices:

The Generic SCSI device driver provides an interface
for sending SCSI commands to all SCSI devices - disks,
tapes, CDROMs, media changer robots, etc.

Speaking of the generic devices as "interfaces" means that
they provide an alternate way of accessing SCSI-hardware than
through the standard devices.
It is necassary because Linux does not allow direct hardware access
through the standard SCSI-devices - everything must pass by the
kernel first. But the writing-software _requires_ direct access to
the CD-writer hardware - so there must be an alternate way.

[Note: if there were a standard for driving CD-writers, the
kernel-developers would have programmed a kernel-module for
writing to CD-Rs and we wouldn't have to use generic devices.
But as every manufacturer needs an individual driver for its
hardware (argh!), this kernel-module would become unhandy and
bigger than everything you want to be in your kernel.]

As everthing can be done to SCSI-hardware through the generic
devices they are not fixed to a certain purpose - therefore the
name "generic".

Goto the "/dev"-directory and check for "generic scsi devices";
"ls"-command should show "sga"-"sgh":

bash> cd /dev
bash> ls -l sg*
crw------- 1 root sys 21, 0 Jan 1 1970 sga
crw------- 1 root sys 21, 1 Jan 1 1970 sgb
crw------- 1 root sys 21, 2 Jan 1 1970 sgc
crw------- 1 root sys 21, 3 Jan 1 1970 sgd
crw------- 1 root sys 21, 4 Jan 1 1970 sge
crw------- 1 root sys 21, 5 Jan 1 1970 sgf
crw------- 1 root sys 21, 6 Jan 1 1970 sgg
crw------- 1 root sys 21, 7 Jan 1 1970 sgh

If you don't have those device-files then create them by using
the "/dev/MAKEDEV"-script:

bash> cd /dev/
bash> ./MAKEDEV sg

Now the device-files should show up.

2.4. Enable usage of the "generic scsi" and "loopback" devices

The Linux-kernel needs a module that lends it the ability to
deal with generic scsi devices.
If your running kernel has this feature, it should be listed
in the pseudo-file "/proc/devices":

bash> cat /proc/devices
Character devices:
1 mem
2 pty
3 ttyp
4 ttyp
5 cua
7 vcs
21 sg <----- stands for "Scsi Generic device"

30 socksys

Block devices:
2 fd
7 loop <----- we even can use the loop-devices
8 sd
11 sr <----- stands for "Scsi cd-Rom"

Maybe you have to issue the commands "insmod sg", "insmod loop"
or "insmod sr_mod" to load the modules into the kernel. Check
again after you've tried this.

If one of them doesn't succeed, you must re-configure your kernel
and re-compile it.

bash> cd /usr/src/linux
bash> make config

[..]
*
* Additional Block Devices
*
Loopback device support (CONFIG_BLK_DEV_LOOP) [M/n/y/?] M

[..]
*
* SCSI support
*
SCSI support (CONFIG_SCSI) [Y/m/n/?]
*
* SCSI support type (disk, tape, CD-ROM)
*
SCSI disk support (CONFIG_BLK_DEV_SD) [Y/m/n/?] Y
SCSI tape support (CONFIG_CHR_DEV_ST) [M/n/y/?] M
SCSI CD-ROM support (CONFIG_BLK_DEV_SR) [M/n/y/?] M
SCSI generic support (CONFIG_CHR_DEV_SG) [M/n/y/?] M

[..]
ISO9660 cdrom filesystem (CONFIG_ISO9660_FS) [Y/m/n/?] M

Please note that I omitted the not-so-important questions.

2.5. Build and install the kernel

If you have questions regarding to this the Linux Kernel-HOWTO
is the suggested reading. Furthermore your Linux-distribution
should ship with some documentation about this issue.

[Hint: while re-compiling, you can continue with steps 2.7-2.9]

2.6. Reboot the computer for the changes to take effect.

Don't panic if the Linux-kernel prints the messages faster than you
can read them, at least the initialization of SCSI-devices can be
re-displayed with the command "dmesg":

scsi0 : NCR53c{7,8}xx (rel 17)
scsi : 1 host.
scsi0 : target 0 accepting period 100ns offset 8 10.00MHz
scsi0 : setting target 0 to period 100ns offset 8 10.00MHz

Vendor: FUJITSU Model: M1606S-512 Rev: 6226
Type: Direct-Access ANSI SCSI
Detected scsi disk sda at scsi0, channel 0, id 0, lun 0

Vendor: NEC Model: CD-ROM DRIVE:84 Rev: 1.0a
Type: CD-ROM ANSI SCSI
Detected scsi CD-ROM sr0 at scsi0, channel 0, id 4, lun 0

scsi : detected 1 SCSI disk total.
SCSI device sda: hdwr sector= 512 bytes. Sectors= 2131992

Shown above is only that part of the initialization-messages
that report the detection of physically present SCSI-devices.

2.7. Create "loopback devices"

Goto the "/dev"-directory and check for "loopback devices".
It's not critical if you don't have those devices, but it's
convenient if you do (see 3.5).
If you already have them, the "ls"-command should show
loop0-loop7:

bash> cd /dev
bash> ls -l loop*
brw-rw---- 1 root disk 7, 0 Sep 23 17:15 loop0
brw-rw---- 1 root disk 7, 1 Sep 23 17:15 loop1
brw-rw---- 1 root disk 7, 2 Sep 23 17:15 loop2
brw-rw---- 1 root disk 7, 3 Sep 23 17:15 loop3
brw-rw---- 1 root disk 7, 4 Sep 23 17:15 loop4
brw-rw---- 1 root disk 7, 5 Sep 23 17:15 loop5
brw-rw---- 1 root disk 7, 6 Sep 23 17:15 loop6
brw-rw---- 1 root disk 7, 7 Sep 23 17:15 loop7

If you don't have those device-files, then create them by using
the "/dev/MAKEDEV"-script:

bash> cd /dev/
bash> ./MAKEDEV loop

The last command only succeeds if you have the "loop"-module in
your kernel (see 2.4 for handling of modules). If "insmod loop"
does not help, you must wait until the new kernel is properly
installed.

2.8. Get the user-software for burning CDs

2.8.1. Command line utilities

The following packages are essential:

ftp://tsx-11.mit.edu/pub/linux/packages/mkisofs/mkisofs-1.10.tar.gz
ftp://sunsite.unc.edu/pub/Linux/utils/disk-management/cdwrite-2.0.tar.gz

Please use the nearest mirrors of these ftp-Servers or download
them from a CD.

Be absolutly sure you have version 2.0 of "cdwrite". No older
version and especially no beta-versions will work properly! Don't
trust the man-page of (old) "mkisofs". The "mkisofs"-package
contains a old version (1.5) of "cdwrite" that will produce no
usable result.

The Debian-Distribution ships with a patch for release 1.05 of
"mkisofs" that adds the option '-K' to it (see 3.4); it's
available from

ftp://ftp.debian.org/pub/debian/rex/source/misc/mkisofs_1.05-3.diff.gz

This patch is only necassary if you want to mount the CD-image
via the loopback-device (see 3.5.).

2.8.2. A graphical user interface (optional)

X-CD-Roast is a graphical frontend (X11) for CD related programs
like "cdwrite-2.0" and "mkisofs-1.05". It's available from

http://www.fh-muenchen.de/home/ze/rz/services/projects/xcdroast/e_overview.html

X-CD-Roast is full X based CD-Writer-Program, and it is the successor
of the "cdwtools-0.93".

3. "If to smoke you turn I shall not cease to fiddle while you burn."
(Emperor nero about burning his own classic-CDs [AD64]; he
misunderstand it completly)

Usally the writing of a CD under Linux is done in 2 steps:

- packaging the desired software into one big file using
the "mkisofs"-utility

- writing the big file to the CD-R with "cdwrite"

It also possible to combine the 2 steps into one via a pipe
but that is discouraged because it's not reliable. See below.

3.1. Determine which generic scsi device the writer is attached to

After following all steps of the second chapter your system
should be able to deal with the task of writing CDs. This
section can be used as a proof that everything works as
intended.

Issue the command "dmesg". It should report the messages of
the Linux-kernel including those printed while booting
(limitation: only the last 200) and contain some information
about the CD-Writer connected to the SCSI-bus.

Simple example:

Vendor: YAMAHA Model: CDR100 Rev: 1.11
Type: WORM ANSI SCSI revision: 02
Detected scsi CD-ROM sr1 at scsi0, channel 0, id 3, lun 0

This machine has 4 SCSI-devices connected to it (you can't see it
so I tell you), with SCSI-id's from 0 to 3. The writer is the
4th physically present SCSI-device and therefore connected to
"/dev/sgd" (the fourth generic SCSI-device when counting is started
with "a").
In this case the command

cdwrite --eject --device /dev/sgd

opens the tray and is a test if everything is set up properly.

A more complicated example:

scsi0 : AdvanSys SCSI 1.5: ISA (240 CDB)
scsi1 : Adaptec 1542
scsi : 2 hosts.

Vendor: HP Model: C4324/C4325 Rev: 1.20
Type: CD-ROM ANSI SCSI revision: 02
Detected scsi CD-ROM sr0 at scsi0, channel 0, id 2, lun 0

Vendor: IBM Model: DPES-31080 Rev: S31Q
Type: Direct-Access ANSI SCSI revision: 02
Detected scsi disk sda at scsi1, channel 0, id 0, lun 0

scsi : detected 1 SCSI cdrom 1 SCSI disk total.
SCSI device sda: hdwr sector= 512 bytes.

In this example two SCSI-controllers host 1 SCSI-device each.
What a waste (they are able to host up to 7 devices each). It's
not my setup so stop asking if I have too much money ...
Anyway for the purpose of being an overlookable example this
setup is just excellent. :-)

In the above example the CD-Writer has SCSI-id 2 but it is
associated with the first generic SCSI-device "/dev/sga" because
it's the first physically present SCSI-device which Linux has
detected.
Hopefully this shows clearly that the SCSI-id of a device has
nothing to do with the associated generic device.

Two questions are left: what happens if you catch the wrong
device?
If you neither specify the option "--<MANUFACTURER>" nor write
any data to the device, usally a warning message is printed and
nothing bad happens:

bash> cdwrite --eject --device /dev/sgb

Unknown CD-Writer; if this model is compatible with any
supported type, please use the appropriate command line
flag.

Manufacturer: IBM
Model: DPES-31080
Revision: S31Q

In this case the device "/dev/sbg" is a scsi harddisk (from IBM).

If you write data to the wrong device, you overwrite the
original content of it and probably irrecoverable damage
your system. Believe me, it already happened to me by accident.

Be careful.

3.2. Collect software

Usally this takes up longer than one expects. Remember that
missing files cannot be added once the CD is written. :-)

Also keep in mind that a certain amount of the free space
of a CD is used for storing the information of the
iso9660-filesystem (usally a few MB).

3.3. Storing data on a CD.

The term "iso9660" refers to the format in which data is
organised on the CD. To be more precise: it's the filesystem on
the CD.

Of course the appearance of files stored in this format is
unified by the Linux-kernel as for every other filesystem, too.
So if you mount a CD into the directory tree, you cannot
distinguish it's files from other files ... beside the fact
that they are not writeable ... even not for root. :-)
(The mechanism used to unify the appearance of files is called
"virtual filesystem", short "VFS".)

The features of the iso9660 filesystem are not so rich compared
to those of the extended-2 filesystem which is normally used
under Linux. On the other hand, the CD is only writable once and
some features make no sense anyway.
The limitations of the iso9660-filesystem are:

- only 8 levels of sub-directories allowed (counted from
the top-level directory of the CD)

- maximum length for filenames: 32 characters

- 650 MB capacity

3.4. Create an iso9660 filesystem

Before any storage medium (e.g. floppy disk, harddisk or CD)
can be used, it must get a filesystem (DOS speak: get formatted).
This filesystem is responsible for organising and incorporating
the files that should be stored on the medium.

Well, the writable CDs are only writable _once_ so if we would
write an empty filesystem to them they would get formated - but
remain completely empty forever. :-)

So what we need is a tool that creates the filesystem while
copying the files to the CD. This tool is called "mkisofs".
A sample usage looks as follows:

mkisofs -r -K -o cd_image private_collection/
`---------' `-----------------'
| |
write output to take directory as "input"

The option '-r' sets the permissions of all files to be public
readable on the CD and enables Rock Ridge extensions. That is
what one usually wants and use of this option is recommended
until you know what you're doing (hint: without '-r' the mount-point
gets the permissions of "private_collection"!).
The option '-K' fixes a bug in the Linux kernel and prevents the
last file on the CD from being "destroyed" (not really, but Linux
can't read it). This option is equivalent to the option '-P' of
"cdwrite".
Please see the manual-page of "mkisofs" for details.

"mkisofs" will try to map all filenames to the 8.3-format used
by DOS to ensure highest possible compatibility. In case of
naming conflicts (different files have the same 8.3-name),
numbers are used in the filenames and information about the
chosen filename is printed via stderr (usually the screen).

DON'T PANIC:

Under Linux you will never see these 8.3 filenames
because Linux makes use of the Rock Ridge extensions
which contain the original file-information (permissions,
filename, etc.).

Now you may wonder why the output of "mkisofs" is not directly
sent to the writer-device. This has two reasons:

(1) "mkisofs" knows nothing about driving CD-writers (see
section 2.3.)
(2) It would not be reliable (see section 4.)

Because the timing of the CD-writer is a critical point, we
don't feed it directly from "mkisofs" (remember Linux is not
a real-time operating system and tasks can be timed badly).
Instead it is recommended to store the output of "mkisofs"
in a separate file on the harddisk.
This file is then an 1:1-image of the later CD and is actually
written to the CD with the tool "cdwrite" in a second step.

The 1:1-image gets stored in a huge file so you need the same
amount of free disk space that your collected software already
eats up. That's a drawback.
One could think of creating an extra partition for that and
writing the image to that partition instead to a file. I vote
against such a strategy because if you write to the wrong
partition (due to a typo), you can lose your complete
Linux-system.
Furthermore, it's a waste of disk-space because the CD-image is
temporary data that can be deleted after writing the CD.

3.5. Test the CD-image

Linux has the ability to mount files as if they were
disk-partitions. This feature is useful to check the directory
layout of the CD-image is ok.

To mount the file "cd_image" created above on the directory
"/cdrom", give the command

mount -t iso9660 -o ro,loop=/dev/loop0 cd_image /cdrom

Now you can inspect the files under /cdrom - they appear
exactly as they were on a "real" CD. To umount the CD-image,
just say "umount /cdrom".
Warning: If you did not use the option "-K" for mkisofs then the
last file on /cdrom is not fully readable.

Note: some ancient versions of "mount" are not able to deal
with loopback-devices. If you have such an old version
of "mount" it is a hint to upgrade your Linux-system.

Several people already suggested to put information
about how to get the newest mount-utilities into this
mini-HOWTO. I always refuse this.
If your Linux-Distribution ships with an ancient "mount":
report it as a bug.
If your Linux-Distribution is not easily upgradable:
report it as a bug.

If I included all the information that is necessary
to work around bugs in bad designed Linux-Distributions,
this mini-HOWTO would be a lot bigger and harder to read.

3.6. Remarks on the blank CD-Recordable discs

The german computer magazine "c't" has a list of tips regarding
the blank CDs in their november 1996 issue:

- "no-name" discs are generally not of highest quality
and should better not be used

- if a recordable CD is defective, this is likely to
apply to the whole batch (if you bought more than one at
a time); maybe you are lucky and can at least use the
first 500MB of such CDs ...

- don't touch the CDs at their shimmering side before
writing

3.7. Write the CD-image to a CD

Not much more left to do. Before showing you the last command,
let me warn you that CD-writers want to be fed with a constant
stream of data because they have no (or only small) data-buffers.
So the process of writing the CD-image to the CD mustn't be
interupted or a corrupt CD will be the result.

To be sure nothing can interupt this process, throw all users
of the system and unplug the ethernet-cable ...
Read the "Bastard operator from hell" to learn about the right
attitude to do so. ;-)

If you are mentally prepared, dress up in a black robe, multiply
the SCSI-id of the CD-writer with it's SCSI-revision and light
as many candles, speak two verses of the ASR-FAQ and finally type

cdwrite --device /dev/sgd cd_image

Of course you have to replace "/dev/sgd" with the generic
SCSI-device your writer is connected to.

Please note that no writer can re-position it's laser and can't
continue at the original spot on the CD when it gets disturbed.
Therefore any strong vibrations or even a shock will
completly destroy the CD you are writing.

3.8. If something goes wrong ...

... remember you can still use corrupt CDs as coasters. :-)

4. Frequently asked questions with answers

4.1. "How sensitive is the burning process?"

Answer: that depends on your writer. Modern ones should have a
data-buffer of 1MB or such and can live 1-2 seconds without data.
See the manuals or ask your manufacturer if you want to know
the details.
Regardless of the size of those data-buffers you must guarantee
a constant throughput of 300kb/s or 600kb/s in the long time run.

Disk intensive processes such as updating the "locate"-database
lower the maximum flow-rate will surely corrupt the CD; you
better check such processes are not started via "cron", "at" or
"anacron".

On the other hand, people reported that they compiled a kernel
while burning a CD without a glitch. Of course you need a _very_
fast machine for such experiments.

4.2. "Has fragmentation a bad impact on the throughput?"

Fragmentation is usally so low that it's impact isn't noticed.

If you're uncertain than look at the messages printed while
booting, the percentage of fragmentation is reported while
checking the filesystems. You can check for this value with
the very dangerous command

bash> e2fsck -n /dev/sda5 # '-n' is important!
[stuff deleted - ignore any errors]
/dev/sda5: 73/12288 files (12.3% non-contiguous)

In this example the fragmentation seems to be very high - but
there are only 73 very small files on this filesystem (used as
"/tmp") so the value is _not_ alarming.

4.3. "Is it possible to store the CD-image on an UMSDOS-filesystem?"

Yes. The only filesystem that isn't reliable and fast enough
for writing CDs from is NFS ("network filesystem").

I'm using UMSDOS myself to share the disk-space between Linux
and DOS/Win on a PC (486/66) dedicated for writing CDs.

4.4. "Isn't there some way to get around the iso9660 limitations?"

Yes. You can put any filesystem you like on the CD. But other
Operating systems than Linux won't be able to deal with this
CD.

Here goes the recipe:

(a) Create an empty file of 650MB size.

dd if=/dev/zero of="empty_file" bs=1024k count=650

(b) Create an extended-2 filesystem on this file

bash> /sbin/mke2fs empty_file
empty_file is not a block special device.
Proceed anyway? (y,n) y

(c) Mount this empty file through the loopback-devices

mount -t ext2 -o loop=/dev/loop1 empty_file /mnt

(d) Copy files to /mnt and umount it afterwards.

(e) Use "cdwrite" on empty_file as if it were an
iso9660-image. Use '-P' as an option to "cdwrite".

If you want to make an entry in /etc/fstab for such a CD, disable
the checking of it, e.g.:

/dev/cdrom /cdrom ext2 defaults,ro 0 0

The first 0 means "don't include in dumps", the second (=important)
one means "don't check for errors on startup".

4.5. "How to read and write audio CDs?"

Please get the packages "cdda2wav" and "sox", available from
sunsite and it's mirrors:

ftp://sunsite.unc.edu/pub/Linux/apps/sound/cds/cdda2wav0.71.src.tar.gz
ftp://sunsite.unc.edu/pub/Linux/apps/sound/convert/sox-11gamma-cb2.tar.gz

"cdda2wav" enables you to get a specific interval (or a whole
track) from your audio CD and converts it into a .wav-file.
"sox" converts the wav-files back into the (audio-CD) cdda-format
so it can be written to the CD-R using "cdwrite".

4.6. "How to probe for SCSI-devices after boot?"

The file "drivers/scsi/scsi.c" contains the information

/*
* Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
* with "0 1 2 3" replaced by your "Host Channel Id Lun".
* Consider this feature BETA.
* CAUTION: This is not for hotplugging your peripherals. As
* SCSI was not designed for this you could damage your
* hardware !
* However perhaps it is legal to switch on an
* already connected device. It is perhaps not
* guaranteed this device doesn't corrupt an ongoing data transfer.
*/

4.7. "Is it possible to make a 1:1 copy of a CD?"

Yes. First case: you have a CD-writer and a seperate CD-ROM
drive. By issuing the command

cdwrite -v -D /dev/sgc --pad -b `isosize /dev/scd0` /dev/scd0

you read the data stream from the CD-ROM drive attached as
/dev/scd0 and write it directly through /dev/sgc to the CD-R.

Second case: you don't have a seperate CD-ROM drive. You have
to use the writer to read out the CD-ROM in this case:

dd if=/dev/scd0 of=cdimage bs=1c count=`isosize /dev/scd0`

This command is equivalent to the result of "mkisofs", so you
should procede as described in chapter 3.

5. Credits

Andreas Erdmann <[email protected]>
provided the example with the YAMAHA-writer

Art Stone <[email protected]>
had the idea to put non-iso9660 filesystems on a CD

Bernhard Gubanka <[email protected]>
noticed the need of a recent version of mount to
utilize the loopback device

Brian H. Toby
polished the wording.

Bruce Perens <[email protected]>
gave information about the cdwrite-mailinglist

Dale Scheetz <[email protected]>
helped improving the section about creating the cdimage.

Edwin H. Kribbs
reported that '-K' requires a patch for mkisofs

Gerald C Snyder <[email protected]>
tested writing of an ext2 CD-ROM (see 4.4)

Ingo Fischenisch <[email protected]>
provided the example with 2 controllers hosting 2 devices

Pierre Pfister <[email protected]>
helped to develop the recipe on 1:1 copies.

Stephan Noy <[email protected]>
information and experience about writing audio-CDs

Stephen Harris <[email protected]>
contributed hint about writing audio-CDs

The Sheepy One <[email protected]>
suggested using defective CDs as coasters for drinks

Volker Kuhlmann <[email protected]>
noticed that the "cdwrite"-package does not contain
"mkisofs"

End of the Linux CD-Writing mini-HOWTO