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CD-Writing HOWTO Winfried Trⁿmper <winni@xpilot.org> v2.7, 11 April 1999 This document explains how to write CD-ROMs under Linux. ______________________________________________________________________ Table of Contents 1. Introduction 1.1 Copyright, license and terms of usage 1.2 Suggested readings 1.3 Terminology ... lasers at maximum ... fire! 1.4 Supported CD-Writers 1.5 Supported "features" 1.6 Mailinglists 1.7 Availability 2. Setup Linux-system for writing CD-ROMs 2.1 Set up the Linux-kernel 2.1.1 Special hints for the 2.2-series 2.1.2 Special hints for the 2.0-series 2.2 Hardware and devicefiles 2.2.1 IDE/ATAPI CD-writers 2.2.2 SCSI CD-Writers 2.2.2.1 Generic SCSI devices 2.2.3 CD-Writers for the parallel port 2.3 Get the user-software for burning CD-Rs 2.3.1 Command line utilities 2.3.2 Graphical user interfaces (optional) 3. Burning CD-Rs 3.1 Writing CD-ROMs (pure data) 3.1.1 Creating an image of the later CD-ROM 3.1.2 Test the CD-image 3.1.3 Write the CD-image to a CD 3.2 Writing audio CDs 3.3 Mixed mode CD-ROMs 4. Frequently asked questions with answers 4.1 "How sensitive is the burning process?" 4.2 "Has fragmentation a bad impact on the throughput?" 4.3 "Is it possible to store the CD-image on an UMSDOS-filesystem?" 4.4 "Isn't there some way to get around the ISO-9660 limitations?" 4.5 "How to read the tracks from audio CDs?" 4.6 "How to probe for SCSI-devices after boot?" 4.7 "Is it possible to make a 1:1 copy of a data CD?" 4.8 "Can Linux read Joliet CD-ROMs?" 4.9 "How do I read/mount CD-ROMs with the CD-writer?" 4.10 "How to put even more data on the CD-R?" 4.11 "How to make bootable CD-ROMs?" 4.12 "How to make CD-ROMs writable somehow?" 4.13 "Is it possible to use several writers at once?" 4.14 "Which media is the best?" 5. Troubleshooting 5.1 It doesn't work: under Linux 5.2 Error-message: No read access for 'dev=2,0'. 5.3 It doesn't work: under DOS and friends 5.4 SCSI errors during the burning phase 6. Credits ______________________________________________________________________ 1. Introduction Many people use Linux to burn CD-ROMs, because it is reliable and easy. No bluescreens while burning and no headaches about getting the right combination of hard- and software. It just works once properly set up. The CD-writing HOWTO explains the setup, how to put data on the media and gives some interesting applications kindly submitted by the readers. 1.1. Copyright, license and terms of usage Copyright Winfried Trⁿmper 1996,1997,1998,1999. All rights reserved. Redistribution and use, with or without modification, are permitted provided that the name of the author may not be used to endorse or promote products derived from this software without specific prior written permission. The author disclaims all warranties with regard to this document, including all implied warranties of merchantability and fitness for a certain purpose; in no event shall the author 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. 1.2. Suggested readings The CD-R FAQ <http://www.fadden.com/cdrfaq/> is a general FAQ about compact-disk recordables (CD-R), CD-writers and the required software. As most CD-writers can be used to read CD-ROMs, too, you may want to read the Linux CD-ROM HOWTO, the Linux SCSI HOWTO and the Linux Kernel HOWTO. 1.3. 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 silver aluminium layer a CD-R 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, although you can leave out some areas for later writing, creating a so called multi-session CD. The CD-ROM rewritable (short: CD-RW) was developed to come around the limitation of CD-R media. Here the laser can not even burn pits into the media, but it can also melt the media back into it's original state. This is possible, because the laser does not really burn holes into the media - you do not see a puff of smoke while burning and no voice from above tells you "target destroyed". What the laser really does is to trigger a phase change, thus the name "phase change devices" for CD-RW-writers. An example for a very similar technique used in daily life is the cleaning car in an ice-hockey stadion: during the pauses of the game, the car drives over the ice and fills the scratches in the ice (-> bits containing some sort of information about the game... hehehe) with melted splinter. This HOWTO deals with the task of writing CD-Rs and CD-RWs. Welcome on board, captain. 1.4. Supported CD-Writers The detailed list of models which have been reported to work or not to work under various Unix-like operating systems is available online from <http://www.guug.de:8080/cgi-bin/winni/lsc.pl>. Here is a comprehensive summary of drives known to work with cdrecord: Acer: CDRW 6206A BTC: BCE 621E (IDE) Compro: CW-7502, CW-7502B Dysan: CRW-1622 Elite: Elite b444.41 Grundig: CDR 100 IPW Guillemot: Maxi CD-R 4X/8X HP: SureStore 4020i, SureStore 6020i, C4324, C4325 CD-Writer+ 7100, CD-Writer+ 7200i, CD-Writer+ 8100i, CD-Writer+ 8110i, Hi-Val: CDD-3610 JVC: XR-W2001, XR-W2010, XR-W2042, R-2626 Kodak: PCD 200, PCD 225, PCD 260, PCD 600 Matsushita: CW-7502 Memorex: CRW-620, CRW-1622 Microboards: PlayWrite 2000, PlayWrite 4000RW, PlayWrite 4001RW MicroNet: MasterCD Plus 4x4, MasterCD Plus 4x6 Mitsubishi: CDRW-226 Mitsumi: CR-2401-TS, CR-2600 TE, CR-2801 TE, CR-4801 TE Nomai: 680.RW OTI: CDRW 965 Olympus: CDS 615E, CDS 620E Optima: DisKovery 650 CD-R OTI: CDRW 965 Panasonic: CW-7502, CW-7582 Philips: CDD-521/10, CDD-522 CDD-2000, CDD-2600, CDD-3600, CDD-3610 Omniwriter 26, Omniwriter 26A Plasmon: CDR 480, CDR 4220, RF-4100, RF-4102, CDR 4400 Plextor: CDR PX-24 CS, PX-412 C, PX-R412 C PX-R810Ti, PleXwriter 412C Procom: PCDR 4 Ricoh: RO-1420C+, MP 1420C, MP 6200S, MP 6201S Sanyo: CRD-R24S Smart and Friendly: CD-RW226, CD-R1002, CD-R1002/PRO, CD-R1004, CD-R2004, CD-R2006 PLUS, CD-R2006 PRO, CD-R4000, CD-R4006, CD-R4012 Sony: CDU 920S, CDU 924, CDU 926S, CDU-928E, CDU 948S, CDRX 100E Taiyo Yuden: EW-50 TEAC: CD-R50S, CD-R55S, CDR-55S Traxdata: CRW 2260, CDR 4120, CDRW 4260, Turtle Beach: 2040R WPI (Wearnes): CDRW-622, CDR-632P YAMAHA: CDR-100, CDR 102, CDR-200, CDR-200t, CDR-200tx CDR-400, CDR-400c, CDR-400t, CDR-400tx, CDR-400Atx CRW-2260, CRW-2260t, CRW-4250tx, CRW-4260 t, CRW-4260 tx, CRW-4261, CRW-4416 S If your hardware isn't supported you can still use Linux to create an image of the later CD. You may wish to do so because most DOS-software cannot deal with RockRidge-Extensions. But then you have to use DOS- Software to write the image to the CD-R. 1.5. Supported "features" There are two classes of utilities for writing CD-Rs: the hardware- drivers and the data-formatters. The hardware drivers support the following features: Supported Feature cdwrite-2.1 cdrecord-1.6 ------------------------------------------------ IDE/ATAPI no yes Parallel Port no yes CD-RW no yes Multisession only partial yes cdwrite is an old software only referenced for completeness. Please use cdrecord instead, as it supports a wider range of hardware and has significantly more features. The purpose of the data-formatters is to organise the data on the media ("put a filesystem on it"). Feature mkisofs mkhybrid -------------------------------------------- ISO 9660 yes yes RockRidge yes yes El Torito yes yes HFS no yes Joliet no yes The most obvious difference of the ISO 9660 filesystem compared to the Extended-2 filesystem is, that you can't modify files once they are written to the media. The limitations of the ISO-9660-filesystem are: ╖ only 8 levels of sub-directories allowed (counted from the top- level directory of the CD) (use RockRidge Extensions to enlarge this number) ╖ maximum length for filenames: 32 characters ╖ 650 MB capacity RockRidge is an extension to allow longer filenames and a deeper directory hierarchy for the ISO-9660 filesystem. These extensions are not available when reading the CD-ROM under DOS or the Windows-family of operating systems. El Torito can be used to produce bootable CD-ROMs. The BIOS of your PC must support this feature, too. Roughly speaking, the first 1.44 Mbyte of the CD-ROM contain a floppy-disk image supplied by you. This image is treated like a floppy by the BIOS and booted from. HFS lets a Macintosh read the CD-ROM as if it were an HFS volume (the native filesystem for MacOS). Joliet brings long filenames (among other things) to newer variants of Windows (95, 98, NT). The author knows of no tool to have long filenames under plain DOS or Windows 3.11. Section 2.8 lists the availability of the mentioned software. 1.6. Mailinglists If you want to join the development team (with the intention to actively help them), send e-mail to cdwrite-request@other.debian.org and put the word subscribe in body of the message. 1.7. Availability The newest version of this document is always available from <http://www.guug.de/~winni/linux/>. 2. Setup Linux-system for writing CD-ROMs If you succeed setting up your hardware and the rest of your Linux- system, the command cdrecord -scanbus shows you a list of devices available for writing. The goal of this chapter is to guide you in setting up your Linux-system, so that you finally end up seeing something like: shell> cdrecord -scanbus Cdrecord release 1.7a1 Copyright (C) 1995-1998 J÷rg Schilling scsibus0: 0) 'Quantum ' 'XP34300 ' 'F76D' Disk 1) 'SEAGATE ' 'ST11200N ' '8334' Disk 2) * 3) 'TOSHIBA ' 'MK537FB/ ' '6258' Disk 4) 'WANGTEK ' '5150ES SCSI-36 ' 'ESB6' Removable Tape 5) 'EXABYTE ' 'EXB-8500-85QUE ' '0428' Removable Tape 6) 'TOSHIBA ' 'XM-3401TASUNSLCD' '3593' Removable CD-ROM 7) * scsibus1: 100) 'Quantum ' 'XP31070W ' 'L912' Disk 101) * 102) * 103) 'TEAC ' 'CD-R55S ' '1.0H' Removable CD-ROM 104) 'MATSHITA' 'CD-R CW-7502 ' '4.02' Removable CD-ROM 105) * 106) 'YAMAHA ' 'CDR400t ' '1.0d' Removable CD-ROM 107) * The example was provided by J÷rg Schilling and shows a total of four cd-writers. You cannot distinguish ordinary CD-ROM drives from those CD-ROM drives with burning capability. But the product identification often has hints about the feature in form of a R, -R or -RW. 2.1. Set up the Linux-kernel The Linux-kernel can be equipped with drivers for various features. You can compile the drivers into the kernel-image statically or you can compile them as a module for loading on-demand. The last method is preferred for drivers not essential for bringing your Linux-system into life. Example: if your system lives on a IDE-harddisk, you must have the driver for IDE-harddisks in the kernel (and not as a module). There are three different types of CD-writers: SCSI, IDE/ATAPI and external writers for the parallel port. Table 4 shows how to configure the Linux-kernel for those hardware types. The first column of the table is the section of the configuration menu, where you can find the setting. The second column is the description of the feature. The third column gives the name of the resulting module. Y stands for yes and means you should put the beast into the kernel. M stands for module and means you should compile this feature as a module. Y/M gives you the option to decide between both. Empty settings don't need to be modified and not changing them increases the chance that the resulting kernel will work for you (if it did before...). To check which drivers are active (provided by both, statical and dynamical drivers) in your running kernel, you can read the file /proc/devices. To check which modules are loaded, issue the command 'lsmod'. To check which modules are available for loading, issue the command 'modprobe -l'. If you need a module not available on your system, you must recompile and reinstall the kernel. Please read the Kernel-HOWTO for more information upon this. The most recent information about handling of kernel-modules can be read in the Module-HOWTO. Sect. Description Module SCSI IDE PP ------------------------------------------------------------ BLOCK Enhanced IDE/MFM/RLL... Y BLOCK IDE/ATAPI CDROM ide-cd M/N/Y BLOCK SCSI hostadaptor emulation ide-scsi M BLOCK Loopback device loop M M M PARIDE Parallel port IDE device paride Y/M PARIDE Parallel port ATAPI CD-ROMs M PARIDE Parallel port generic ATAPI M PARIDE (select a low-level driver) Y SCSI SCSI support scsi_mod Y/M Y/M SCSI SCSI CD-ROM support sr_mod Y/M Y/M SCSI Enable vendor-specific Y Y SCSI SCSI generic support sg Y/M Y/M SCSI (select a low-level driver) Y FS ISO 9660 CDROM filesystem iso9660 Y Y Y FS Microsoft Joliet cdrom... joliet M M M If you have success in building or finding the required modules, either add their names to /etc/modules or let an automatic facility (kmod, kerneld) load them. Consult the documentation of your Linux- distribution if you are unsure. The feature "SCSI hostadaptor emulation" was named "SCSI emulation" in earlier kernels (around 2.0.36). If your kernel allows it, compile the driver for IDE/ATAPI CD-ROMs as a module. If not, disable it (N) and use the driver for SCSI-CD-ROMs instead. For the 2.2 series of the Linux kernel, it is no longer possible to run the drivers for IDE and SCSI on the same physical device at the same time (if you still have 2.0.36, read below). The loopback device is an optional feature, which helps you to test the image before writing it to the media. If you want to be able to read CD-ROMs, you need support for the ISO 9660 filesystem. This driver automatically includes RockRidge Extensions. If you want to have MS Joliet cdrom extensions, compile them as a module and load them. In any case, you need a low-level driver for your hardware. Low-level refers to the driver, which interacts directly with the hardware. For SCSI and the parallel port, there are a lot of low-level drivers available, which are described below. 2.1.1. Special hints for the 2.2-series With kernel-version 2.2.1, don't enable CONFIG_SCSI_MULTI_LUN ('probe for multiple luns') and ide-scsi support at the same time, there is an ide-scsi bug that prevents this. Anyway, it is recommended to upgrade to 2.2.5. Some users reported conflicts with pre-compiled binaries and the 2.2-release. This is a problem of the Linux-kernel. Solutions: ╖ It may go away if you recompile cdrecord so that it adopts to the actual values in linux/include/scsi/sg.h. These values must be the values of the runing kernel due to the dumb sg user interface. ╖ It may be caused by a loabdable sg driver which cannot get enough memory that is suitable for DMA. Get the sg_buffer patch from J÷rg Schillings FTP-site: <ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/alpha/> 2.1.2. Special hints for the 2.0-series Kernels prior to 2.0.31 have several bugs and can't read the last file on a CD-ROM. Please upgrade to 2.0.36. With 2.0.36 and above, you can select which driver (IDE or SCSI) to use for which ATAPI-device. To be more precise, you can add the feature "SCSI emulation" to your kernel and activate the emulation for specific devices on the kernel commandline (before/while booting). For example, if your cd-writer has the devicefile /dev/hdb, then add the statement hdb=ide-scsi. image=/boot/zImage-2.0.36 label=Linux read-only append="hdb=ide-scsi" linux "Linux 2.0.36" { image=/boot/zImage-2.0.36 cmdline= root=/dev/hda5 readonly hdb=ide-scsi } 2.2. Hardware and devicefiles After you have installed all necassary drivers, boot the new kernel. It should have all the features you need for the following sections. [Users of devfs need not to care about the following steps of manually setting up device files. If you use devfs, everything will automacigally appear on the right place.] 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: shell> cd /dev shell> ls loop* loop0 loop1 loop2 loop3 loop4 loop5 loop6 loop7 If you don't have those device-files, then create them by using the /dev/MAKEDEV-script: shell> cd /dev/ shell> modprobe loop shell> ./MAKEDEV loop The last command only succeeds if you have the loop-module in your kernel. What you read so far about handling of loop-devicefiles can be applied to all other devicefiles (sg*, pg*, hd*, ...) and is not explicitely mentioned in the following. 2.2.1. IDE/ATAPI CD-writers ATAPI means "SCSI-commands over the IDE-bus". In other words, your IDE/ATAPI-drives speak the SCSI-protocol (with some limitations) and thus can act as if they were SCSI-drives. Under Linux you can make your IDE-writer appear as a SCSI-devices using the kernel-features "SCSI (hostadaptor) emulation". So activate the associated kernel module ide-scsi like described above and proceed as if you had a SCSI-writer. 2.2.2. SCSI CD-Writers Please make sure that your writer is recognized by the BIOS of your computer. It makes no sense to proceed if your computer does not accept the hardware (the fact that it doesn't spit it out is no confirmation; a message on the screen is required). If you plan to connect your SCSI-drive to your parallel port, you need a special active cable and a special kernel-driver. Read read <http://www.torque.net/parport/parscsi.html> to learn more about this option. 2.2.2.1. Generic SCSI devices The devicefiles /dev/sd* and /dev/sr* for accessing SCSI harddisks and SCSI CD-ROM drives are limited to block-oriented data transfer. This makes them so fast and idealy suited for data storage. Driving the laser of a CD-writer is a more complicated task and requires more than block-oriented data transfer. To keep the sd* and sr* devices clean and fast, a new type of SCSI-devices was introduced, the so called generic SCSI-devices. As everthing can be done to SCSI-hardware through the generic devices they are not fixed to a certain purpose - therefore the name generic. As true for other devices, you should find them in the /dev directory (by convention): shell> cd /dev shell> ls sg* sg0 sg1 sg2 sg3 sg4 sg5 sg6 sg7 If you don't have those device-files then create them by using the /dev/MAKEDEV-script: shell> cd /dev/ shell> ./MAKEDEV sg 2.2.3. CD-Writers for the parallel port I have no clue about this, sorry. Please read <http://www.torque.net/parport/paride.html> or your local file /usr/src/linux/Documentation/paride.txt. 2.3. Get the user-software for burning CD-Rs A survey of tools related to produce CD-ROMs is available from <http://www.fokus.gmd.de/research/cc/glone/employees/joerg.schilling/private/cdb.html>.The CD building project for UNIX 2.3.1. Command line utilities One of the following packages are required to generate prototypes of CD-Rs: <ftp://tsx-11.mit.edu/pub/linux/packages/mkisofs/> (mkisofs) <ftp://ftp.ge.ucl.ac.uk/pub/mkhfs> (mkhybrid) Depending on the model of your CD-writer (see 1.3), one of the following software for writing prototypes to CD-Rs is required: <ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/> (cdrecord) Don't trust the man-page of (old) mkisofs which states you need version 1.5 of cdwrite. Just use cdrecord and you are fine. Please note that use the mkisofs shipped with cdrecord has a few extensions (referenced in the documentation of cdrecord). 2.3.2. Graphical user interfaces (optional) Front-ends are really front-ends under Linux. That means, you still have to install the command-line utilities, but you access them in a better looking manner. X-CD-Roast is a program-package dedicated to easy CD creation under Linux. It combines command line tools like cdrecord and mkisofs into a nice graphical user interface. <http://www.fh-muenchen.de/home/ze/rz/services/pro¡ jects/xcdroast/e_overview.html> BurnIT is a JAVA front-end to cdrecord, mksiofs and cdda2wav-0.95 making it a complete package for burning CD's on the Unix platform. It's available from <http://sunsite.auc.dk/BurnIT/> 3. Burning CD-Rs "If to smoke you turn I shall not cease to fiddle while you burn." (Roman emperor Nero about burning his own classic- CDs, AD64. He misunderstood it completely.) Writing CD-ROMs consists of two steps under Linux: ╖ packaging the desired data (files, music or both) into files with special formats ╖ writing the data from the files to the CD-R with the utility cdrecord This chapter describes the steps for data- and audio-CDs in greater detail. 3.1. Writing CD-ROMs (pure data) Note that collecting the software usually takes up longer than one expects. Consider that missing files cannot be added once the CD is written and fixated. Also keep in mind that a certain amount of the free space of a CD is used for storing the information of the ISO-9660-filesystem (usually a few MB). 620 MB data will always fit on a 650 MB CD-R. 3.1.1. Creating an image of the later CD-ROM Before any storage medium (e.g. floppy disk, harddisk or CD) can be used, it must get a filesystem (DOS speak: get formatted). The filesystem is responsible for organising and incorporating the files that should be stored on the medium. The usal utilities for creating filesystems on harddisk partitions write an empty filesystem onto them, which is then mounted and filled with files by the user as he needs it. A writable CD is only writable once so if we would write an empty filesystem to it, it would get formated - but remain completely empty forever. This is also true for rewritable media, as you cannot change arbritary sectors, but you must erase their whole content. 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 -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!). 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: ╖ mkisofs knows nothing about driving CD-writers. ╖ You may want to test the image before burning it. ╖ On slow machines it would not be reliable (see section 4.). The method to write a CD-R in one go will be described below. One also could think of creating an extra partition 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 (read: that happened to me...). Furthermore, it's a waste of disk-space because the CD-image is temporary data that can be deleted after writing the CD. However, using raw partitions saves you the time for deleting files of 650 MB size. (However, if you have enough disk-space, an extra partition may save you the time of deleting the image.) 3.1.2. Test the CD-image Linux has the ability to mount files as if they were disk-partitions. This feature is useful to check that the directory layout and file access permissions of the CD-image matches your wishes. Although media is very cheap today, the writing process is still time-consuming, and you may at least want to save your time by doing a quick test. 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: On Linux-kernels prior to 2.0.31 the last file on /cdrom may not be fully readable. Please use more recent kernels like 2.0.36. The option -pad for cdrecord applies to audio-CDs only and the optional option -pad for mkisofs requires a patch, which is as much work to apply than to upgrade to a bug-free Linux-kernel.) 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 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 had included all the information that is necessary to work around bugs in bad designed Linux-Distributions, this HOWTO would be a lot bigger and harder to read. 3.1.3. Write the CD-image to a CD Not much more left to do. If you didn't already tried, it's a good time for the command cdrecord -scanbus This will tell you to which SCSI-device your cd-writer is attached to. All other methods of guessing the information printed so nicely by cdrecord have been removed from the HOWTO (especially the somewhat dangerous naming scheme for generic SCSI devices). 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 only small data-buffers. So the process of writing the CD-image to the CD must not be interupted or a corrupt CD will be the result. It's easy to interrupt the data-stream by deleting a very large file. Example: if you delete a file of 650 Mbyte size, the kernel must update information about 650.000 blocks on the harddisk (assumed you have a blocksize of 1 Kbyte for your filesystem). That takes some time and is very likely to slow down disk-activity long enough for the data stream to pause a few seconds. However, reading mail, browsing the web or even compiling a kernel generally do not affect the writing process on fast machines. 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 other mechanical shocks will probably destroy the CD you are writing. 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 (newsgroup alt.sysadmin.recovery) and finally type: shell> SCSI_BUS=0 # taken from listing 1 "scsibus0:" shell> SCSI_ID=6 # taken from listing 1 "TOSHIBA XM-3401" shell> SCSI_LUN=0 shell> cdrecord -v speed=2 dev=$SCSI_BUS,$SCSI_ID,$SCSI_LUN \ -data cd_image # same as above, but shorter: shell> cdrecord -v speed=2 dev=0,6,0 -data cd_image For better readability, the coordinates of the writer are stored in three environment variables with speaking names: SCSI_BUS, SCSI_ID, SCSI_LUN. The option -data is non-mandatory but is given to make the commandline comparable to the one used for writing audio-CDs. If you use cdrecord to overwrite a CD-RW, you must add the option "blank=..." to erase the old content. Please read the man-page to learn more about the various methods to blank the CD-RW. In times where everybody except me owns a 400 Mhz machine, people feed the output of mkisofs directly into cdrecord: shell> IMG_SIZE=`mkisofs -R -q -print-size private_collection/` shell> mkisofs -r private_collection/ \ |cdrecord speed=2 dev=0,6,0 tsize=${IMG_SIZE}s -data - # don't forget the s --^ ^-- read data from STDIN The first command is an empty run to determine the size of the image (you need the mkisofs from the cdrecord-distribution for this to work). Maybe your writer does not need to know the size of the image to be written, so you can leave this out. The printed sized must be passed as a tsize-parameter to cdrecord (it's stored in the enviroment variable IMG_SIZE). The last command is a sequence of mkisofs and cdrecord, coupled via a pipe. 3.2. Writing audio CDs To write audio-CDs is very similar compared to the steps described above. The two main differences are, that the audio-CD consists of audio-tracks, which are organized in separate images. So if you want to have ten tracks on your CD, you have to make ten images. The other differnce is, that the format of the images is not ISO-9660 (or whatever filesystem you prefer), but it is "16 bit stereo samples in PCM coding at 44100 samples/second (44,1 kHz)". One utility to convert your soundfiles into the required format is sox. It's usage is straightforward: shell> sox killing-my-software.wav killing-my-software.cdr This command would convert the song killing-my-software from the WAV- format into the CDR-format. See the man-page for sox for more details about formats and filename-extensions sox recognizes. Because the conversion takes up much diskspace, it was made a built-in feature of cdrecord for the formats WAV and AU. So as long as your soundfiles have the extensions .wav or .au (and the samplerate "stereo, 16 bit, 44,1 kHz"), you can use them as images without manual conversion. Cdrecord writes the images as audio-tracks, if the option -audio is specified. The other options are identical to those used for writing data-CDs (unless you have very special requirements). Three examples all doing the same, but reading the tracks from different soundfile- formats: shell> cdrecord -v speed=2 dev=0,6,0 -audio track1.cdr track2.cdr... shell> cdrecord -v speed=2 dev=0,6,0 -audio track1.wav track2.wav... shell> cdrecord -v speed=2 dev=0,6,0 -audio track1.au track2.au... A special case are the MPEG3-files, which can be converted to the required format with the command "mpg123 -s track1.mp3 > track1.cdr". The other direction can be done with "8hz-mp3" for WAV-files. Currently you will produce an audio-CD, which has a 2 seconds pause between two audio tracks. If your burner supports to write the mode "disc at once" (DAO), you can try the newest version of cdrecord to get rid of the pauses. 3.3. Mixed mode CD-ROMs Not much left to say. Just indicate the type of the (subsequent) images with the options -data and -audio. Example: cdrecord -v dev=0,6,0 -data cd_image -audio track*.cdr 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 larger 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 may corrupt the CD; you better check such processes are not started via cron, at or anacron while you burn CD- Rs. On the other hand, people reported that they compiled a kernel while burning a CD without a glitch. Of course you need a fast machine for such experiments. 4.2. "Has fragmentation a bad impact on the throughput?" Fragmentation is usually so low that it's impact isn't noticed. However, you can easily construct pathological cases of fragmentation, which lower the throughput of your harddisks under 100 kbyte/second. So don't do that. :-) Yes, files on a harddisk get fragmented over the years. The faster, the fuller the filesystem is. Always leave 10% or 20% free space, and you should run fine with respect to writing CD-Rs. If you're uncertain then 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 shell> 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. There is an experimental utility called e2defrag to defragment extended-2 filesystems. The current version does not work reliable enough yet, to use it even for private environments. If you really want to defragment your filesystem, make a backup copy (better: two copies), practise restoring the data, then create a new filesystem (will destroy the old) and restore the data. In a few words, this is currently the safest technique. 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 CD-ROMs from is the network filesystem (NFS). I'm using UMSDOS myself to share the disk-space between Linux and DOS/Win on a PC (486/66) dedicated for writing CD-ROMs. 4.4. "Isn't there some way to get around the ISO-9660 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: ╖ Create an empty file of 650MB size. dd if=/dev/zero of="empty_file" bs=1024k count=650 ╖ Create an extended-2 filesystem on this file shell> /sbin/mke2fs -b 2048 empty_file empty_file is not a block special device. Proceed anyway? (y,n) y ╖ Mount this empty file through the loopback-devices mount -t ext2 -o loop=/dev/loop1 empty_file /mnt ╖ Copy files to /mnt and umount it afterwards. ╖ Use cdrecord on empty_file (which is no longer empty) as if it were an ISO-9660-image. 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" (fsck will fail to check the CD for errors). 4.5. "How to read the tracks from audio CDs?" There are several software packages available. The newest one is "cdpranoia" and can be downloaded from <http://www.mit.edu/afs/sipb/user/xiphmont/cdpara¡ noia/index.html> Or you want to try the combination of "cdda2wav" and "sox", available from sunsite and it's mirrors: <ftp://sun¡ site.unc.edu/pub/Linux/apps/sound/cdrom/cdda2wav0.71.src.tar.gz> <ftp://sunsite.unc.edu/pub/Linux/apps/sound/convert/sox-11gamma- cb3.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 cdrecord. You don't necassarily need sox if you use a recent version of cdrecord, because it has built-in support for .au and .wav files. 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. */ Please note that this should only be used if your add SCSI-devices at the end of the chain. Inserting new SCSI-devices into an existing chain disturbs the naming of devices (directory /dev) and may destroy the complete content of your harddisk. 4.7. "Is it possible to make a 1:1 copy of a data CD?" Yes. But you should be aware of the fact that any errors while reading the original (due to dust or scratches) will result in a defective copy. First case: you have a CD-writer and a separate CD-ROM drive. By issuing the command cdrecord -v dev=3,0 speed=2 -isosize /dev/scd0 you read the data stream from the CD-ROM drive attached as /dev/scd0 and write it directly through the SCSI-device with ID 3 to the CD-R. Second case: you don't have a separate CD-ROM drive. You have to use the writer to read out the CD-ROM in this case: dd if=/dev/scd0 of=cdimage This command is equivalent to the result of mkisofs, so you should procede as described in chapter 3. Please note that this method will fail on audio CDs! 4.8. "Can Linux read Joliet CD-ROMs?" Yes. Newer Kernels (2.0.36 and the upcoming 2.2) have built-in support for the joliet format. Remember you have to use both options in your /etc/fstab: the keywords iso9660 and joliet (later is really an extension). For more details, see <http://www- plateau.cs.berkeley.edu/people/chaffee/joliet.html>. 4.9. "How do I read/mount CD-ROMs with the CD-writer?" Just as you do with regular CD-ROM drives. No tricks at all. Note that you have to use the scd-devices (SCSI CD-ROM) to mount CD-ROMs for reading. Example-entry for /etc/fstab: /dev/scd0 /cdrom iso9660 ro,user,noauto 0 0 4.10. "How to put even more data on the CD-R?" Use bzip2 instead of any other compressor like gzip or pkzip. It will save you up to 30% of disk-space for larger (>100kb) files. You can download it from <http://www.muraroa.demon.co.uk/> Instead of writing a true audio-CD, you can optionally convert your wav-audio-files into mp3-audio-files and store them on a ISO-9660 filesystem as regular files. Usually MPEG III gives you a compression of 1:10. Of course, most CD-players are not able to read files... this is the drawback. On the other hand, why not running the music for your next party from harddisk? 18 Gbyte are enough for 3000-4000 titles. :-) A software MPEG III-encoder is available from <http://www.stud.ifi.uio.no/~larsi/other/8hz- mp3-cheng.tar.gz> A MPEG III-player is available from <http://homepages.uni-tuebingen.de/stu¡ dent/michael.hipp/mpg123/> For recorded speech, you may want to try to reduce its size using shorten or "GSM lossy speech compression": <ftp://svr-ftp.eng.cam.ac.uk/pub/comp.speech/> <http://kbs.cs.tu-berlin.de/~jutta/toast.html> 4.11. "How to make bootable CD-ROMs?" You must have an 1.44 MB bootable floppy-disk. Create an exact image of this floppy-disk by issuing the command dd if=/dev/fd0 of=boot.img bs=18k Place this floppy-image into the directory holding the collection of your files (or into a subdirectory of it, just as you like). Tell mkisofs about this file with the option '-b' and also use '-c'. For details read the file README.eltorito in the mkisofs-distribution. An interesting application for a custom bootable CD is as a virus-safe DOS- or Windows-system. It saves you the money for the harddisks (if you have a network and use samba to put the user-data on a fileserver). However, this is purely theoretical as nobody reported an actual recipe to me. Some details about the bootable RedHat CD-ROM is available from <http://www.channel1.com/users/rodsmith/rhjol-technical.html>. 4.12. "How to make CD-ROMs writable somehow?" There is an overlay-filesystem available for Linux, which is mounted over the CD-ROM and intercepts all writing operations. New and modified files are stored elsewhere, but for the user it looks like the CD-ROM is modified. For more information, see <http://home.att.net/~artnaseef/ovlfs/ovlfs.html>. If that is not enough for your needs: wait for the UDF-filesystem to be supported by Linux or help developing it (see <http://trylinux.com/projects/udf/>. 4.13. "Is it possible to use several writers at once?" Yes. However, it has been only tested with two writers yet. And you need a kernel patch for more buffers in the SCSI-generic driver ( <ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/alpha>). 4.14. "Which media is the best?" The german computer magazine "c't" had a list of tips regarding the blank CD-Rs 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 CD-Rs ... ╖ Don't touch the CD-Rs at their shimmering side before writing. 5. Troubleshooting Always remember, that you can still use corrupt CD-ROMs as coasters. :-) 5.1. It doesn't work: under Linux Please check first if the writer works under other operating systems. Concretely: ╖ Does the controller recognize the writer as a SCSI device? ╖ Does the driver software recognize the writer? ╖ Is it possible to make a CD using the accompanied software? If "it doesn't work" even under other operating systems you have a hardware conflict or defective hardware. If it works under the other operating system and you use loadlin to boot Linux, then that is your problem. Loadlin makes a warm-boot with most of the hardware already initialized and that confuses the Linux- kernel. 5.2. Error-message: No read access for 'dev=2,0'. Under Linux, some versions of the C-library are incompatible (buggy), so that an application linked against one version will not work with another. An example for an error triggered by pre-compiled binaries is the following: [root@Blue /dev]# cdrecord -eject dev=2,0 cdrecord: No such file or directory. No read access for 'dev=2,0'. 5.3. It doesn't work: under DOS and friends Try to use Linux. Installation and configuration of SCSI-drivers for DOS is the hell. Linux is too complicated? Ha! 5.4. SCSI errors during the burning phase Most likely those errors are caused by ╖ missing dis-/reconnect feature on the SCSI bus ╖ unsufficiently cooled hardware ╖ defective hardware (should be detected by 5.1.) Under various circumstances SCSI devices dis- and reconnect themselves (electronically) from the SCSI bus. If this feature is not available (check controller and kernel parameters) some writers run into trouble during burning or fixating the CD-R. Especially the NCR 53c7,8xx SCSI driver has the feature disabled by default, so you might want to check it first: NCR53c7,8xx SCSI support [N/y/m/?] y always negotiate synchronous transfers [N/y/?] (NEW) n allow FAST-SCSI [10MHz] [N/y/?] (NEW) y allow DISCONNECT [N/y/?] (NEW) y 6. Credits Alan Brown <alan@manawatu.net.nz> Art Stone <stone@math.ubc.ca> had the idea to put non-ISO-9660 filesystems on a CD Bartosz Maruszewski <B.Maruszewski@zsmeie.torun.pl> reported spelling mistakes Bernhard Gubanka <beg@ipp-garching.mpg.de> noticed the need of a recent version of mount to utilize the loopback device Robert Doolittle <bob.doolittle@sun.com> good arguments for dropping cdwrite from the HOWTO Brian H. Toby polished the wording. Martin Schulze <joey@Infodrom.North.DE> gave information about the cdwrite-mailinglist Dale Scheetz <dwarf@polaris.net> helped improving the section about creating the cdimage. Don H. Olive <don@andromeda.campbellsvil.edu> URL of the mkhybrid tool Erwin Zoer <ezoer@wxs.nl> Gerald C Snyder <gcsnyd@loop.com> tested writing of an ext2 CD-ROM (see 4.4) Janne Himanka <shem@oyt.oulu.fi> pointer to kernel patch to read Joliet CD-ROMs Joerg Schilling <schilling@fokus.gmd.de> information about cdrecord Jos van Geffen <jos@tnj.phys.tue.nl> noted the problem in 4.9. Markus Dickebohm <m.dickebohm@uni-koeln.de> Jesper Pedersen <jews@imada.ou.dk> Pierre Pfister <pp@uplift.fr> helped to develop the recipe on 1:1 copies. Rick Cochran <rick@msc.cornell.edu> hint about dis-/reconnect disabled by default in the ncr driver Stephan Noy <stnoy@mi.uni-koeln.de> information and experience about writing audio-CDs Stephen Harris <sweh@mpn.com> contributed hint about writing audio-CDs The Sheepy One <kero@escape.com> suggested using defective CD-ROMs as coasters for drinks Martti.Rahkila@hut.fi Reported problem with pre-initialized writers when booting via loadlin. End of the Linux CD-Writing HOWTO