1. Introduction¶

The ide-cd driver should work with all ATAPI ver 1.2 to ATAPI 2.6 compliantCDROM drives which attach to an IDE interface. Note that some CDROM vendors(including Mitsumi, Sony, Creative, Aztech, and Goldstar) have madeboth ATAPI-compliant drives and drives which use a proprietaryinterface. If your drive uses one of those proprietary interfaces,this driver will not work with it (but one of the other CDROM driversprobably will). This driver will not work withATAPI drives whichattach to the parallel port. In addition, there is at least one drive(CyCDROM CR520ie) which attaches to the IDE port but is not ATAPI;this driver will not work with drives like that either (but see theaztcd driver).

This driver provides the following features:

• Reading from data tracks, and mounting ISO 9660 filesystems.
• Playing audio tracks. Most of the CDROM player programs floatingaround should work; I usually use Workman.
• Multisession support.
• On drives which support it, reading digital audio data directlyfrom audio tracks. The program cdda2wav can be used for this.Note, however, that only some drives actually support this.
• There is now support for CDROM changers which comply with theATAPI 2.6 draft standard (such as the NEC CDR-251). This additionalfunctionality includes a function call to query which slot is thecurrently selected slot, a function call to query which slots containCDs, etc. A sample program which demonstrates this functionality isappended to the end of this file. The Sanyo 3-disc changer(which does not conform to the standard) is also now supported.Please note the driver refers to the first CD as slot # 0.

2. Installation¶

0. The ide-cd relies on the ide disk driver. SeeDocumentation/ide/ide.rst for up-to-date information on the idedriver.

1. Make sure that the ide and ide-cd drivers are compiled into thekernel you’re using. When configuring the kernel, in the sectionentitled “Floppy, IDE, and other block devices”, say eitherY(which will compile the support directly into the kernel) orM(to compile support as a module which can be loaded and unloaded)to the options:

   ATA/ATAPI/MFM/RLL supportInclude IDE/ATAPI CDROM support

   Depending on what type of IDE interface you have, you may need tospecify additional configuration options. SeeDocumentation/ide/ide.rst.

2. You should also ensure that the iso9660 filesystem is eithercompiled into the kernel or available as a loadable module. Youcan see if a filesystem is known to the kernel by catting/proc/filesystems.

3. The CDROM drive should be connected to the host on an IDEinterface. Each interface on a system is defined by an I/O portaddress and an IRQ number, the standard assignments being0x1f0 and 14 for the primary interface and 0x170 and 15 for thesecondary interface. Each interface can control up to two devices,where each device can be a hard drive, a CDROM drive, a floppy drive,or a tape drive. The two devices on an interface are calledmasterandslave; this is usually selectable via a jumper on the drive.

   Linux names these devices as follows. The master and slave deviceson the primary IDE interface are calledhda andhdb,respectively. The drives on the secondary interface are calledhdc andhdd. (Interfaces at other locations get other lettersin the third position; see Documentation/ide/ide.rst.)

   If you want your CDROM drive to be found automatically by thedriver, you should make sure your IDE interface uses either theprimary or secondary addresses mentioned above. In addition, ifthe CDROM drive is the only device on the IDE interface, it shouldbe jumpered asmaster. (If for some reason you cannot configureyour system in this manner, you can probably still use the driver.You may have to pass extra configuration information to the kernelwhen you boot, however. See Documentation/ide/ide.rst for moreinformation.)

4. Boot the system. If the drive is recognized, you should see amessage which looks like:

   hdb: NEC CD-ROM DRIVE:260, ATAPI CDROM drive

   If you do not see this, see section 5 below.

5. You may want to create a symbolic link /dev/cdrom pointing to theactual device. You can do this with the command:

   ln -s  /dev/hdX  /dev/cdrom

   where X should be replaced by the letter indicating where yourdrive is installed.

6. You should be able to see any error messages from the driver withthedmesg command.

3. Basic usage¶

An ISO 9660 CDROM can be mounted by putting the disc in the drive andtyping (as root):

mount -t iso9660 /dev/cdrom /mnt/cdrom

where it is assumed that /dev/cdrom is a link pointing to the actualdevice (as described in step 5 of the last section) and /mnt/cdrom isan empty directory. You should now be able to see the contents of theCDROM under the /mnt/cdrom directory. If you want to eject the CDROM,you must first dismount it with a command like:

umount /mnt/cdrom

Note that audio CDs cannot be mounted.

Some distributions set up /etc/fstab to always try to mount a CDROMfilesystem on bootup. It is not required to mount the CDROM in thismanner, though, and it may be a nuisance if you change CDROMs often.You should feel free to remove the cdrom line from /etc/fstab andmount CDROMs manually if that suits you better.

Multisession and photocd discs should work with no special handling.The hpcdtoppm package (ftp.gwdg.de:/pub/linux/hpcdtoppm/) may beuseful for reading photocds.

To play an audio CD, you should first unmount and remove any dataCDROM. Any of the CDROM player programs should then work (workman,workbone, cdplayer, etc.).

On a few drives, you can read digital audio directly using a programsuch as cdda2wav. The only types of drive which I’ve heard supportthis are Sony and Toshiba drives. You will get errors if you try touse this function on a drive which does not support it.

For supported changers, you can use thecdchange program (appended tothe end of this file) to switch between changer slots. Note that thedrive should be unmounted before attempting this. The program takestwo arguments: the CDROM device, and the slot number to which you wishto change. If the slot number is -1, the drive is unloaded.

4. Common problems¶

This section discusses some common problems encountered when trying touse the driver, and some possible solutions. Note that if you areexperiencing problems, you should probably also reviewDocumentation/ide/ide.rst for current information about the underlyingIDE support code. Some of these items apply only to earlier versionsof the driver, but are mentioned here for completeness.

In most cases, you should probably check withdmesg for any errorsfrom the driver.

1. Drive is not detected during booting.

   • Review the configuration instructions above and inDocumentation/ide/ide.rst, and check how your hardware isconfigured.

   • If your drive is the only device on an IDE interface, it shouldbe jumpered as master, if at all possible.

   • If your IDE interface is not at the standard addresses of 0x170or 0x1f0, you’ll need to explicitly inform the driver using alilo option. See Documentation/ide/ide.rst. (This feature wasadded around kernel version 1.3.30.)

   • If the autoprobing is not finding your drive, you can tell thedriver to assume that one exists by using a lilo option of theformhdX=cdrom, where X is the drive letter corresponding towhere your drive is installed. Note that if you do this and yousee a boot message like:

     hdX: ATAPI cdrom (?)

     this does _not_ mean that the driver has successfully detectedthe drive; rather, it means that the driver has not detected adrive, but is assuming there’s one there anyway because you toldit so. If you actually try to do I/O to a drive defined at anonexistent or nonresponding I/O address, you’ll probably geterrors with a status value of 0xff.

   • Some IDE adapters require a nonstandard initialization sequencebefore they’ll function properly. (If this is the case, therewill often be a separate MS-DOS driver just for the controller.)IDE interfaces on sound cards often fall into this category.

     Support for some interfaces needing extra initialization isprovided in later 1.3.x kernels. You may need to turn onadditional kernel configuration options to get them to work;see Documentation/ide/ide.rst.

     Even if support is not available for your interface, you may beable to get it to work with the following procedure. First bootMS-DOS and load the appropriate drivers. Then warm-boot linux(i.e., without powering off). If this works, it can be automatedby running loadlin from the MS-DOS autoexec.

2. Timeout/IRQ errors.

• If you always get timeout errors, interrupts from the drive areprobably not making it to the host.
• IRQ problems may also be indicated by the messageIRQ probe failed (<n>) while booting. If <n> is zero, thatmeans that the system did not see an interrupt from the drive whenit was expecting one (on any feasible IRQ). If <n> is negative,that means the system saw interrupts on multiple IRQ lines, whenit was expecting to receive just one from the CDROM drive.
• Double-check your hardware configuration to make sure that the IRQnumber of your IDE interface matches what the driver expects.(The usual assignments are 14 for the primary (0x1f0) interfaceand 15 for the secondary (0x170) interface.) Also be sure thatyou don’t have some other hardware which might be conflicting withthe IRQ you’re using. Also check the BIOS setup for your system;some have the ability to disable individual IRQ levels, and I’vehad one report of a system which was shipped with IRQ 15 disabledby default.
• Note that many MS-DOS CDROM drivers will still function even ifthere are hardware problems with the interrupt setup; theyapparently don’t use interrupts.
• If you own a Pioneer DR-A24X, you _will_ get nasty error messageson boot such as “irq timeout: status=0x50 { DriveReady SeekComplete }”The Pioneer DR-A24X CDROM drives are fairly popular these days.Unfortunately, these drives seem to become very confused when we performthe standard Linux ATA disk drive probe. If you own one of these drives,you can bypass the ATA probing which confuses these CDROM drives, byaddingappend=”hdX=noprobe hdX=cdrom” to your lilo.conf file and runninglilo (again where X is the drive letter corresponding to where your driveis installed.)

3. System hangups.

• If the system locks up when you try to access the CDROM, the mostlikely cause is that you have a buggy IDE adapter which doesn’tproperly handle simultaneous transactions on multiple interfaces.The most notorious of these is the CMD640B chip. This problem canbe worked around by specifying theserialize option whenbooting. Recent kernels should be able to detect the need forthis automatically in most cases, but the detection is notfoolproof. See Documentation/ide/ide.rst for more informationabout theserialize option and the CMD640B.
• Note that many MS-DOS CDROM drivers will work with such buggyhardware, apparently because they never attempt to overlap CDROMoperations with other disk activity.

4. Can’t mount a CDROM.

• If you get errors from mount, it may help to checkdmesg to seeif there are any more specific errors from the driver or from thefilesystem.

• Make sure there’s a CDROM loaded in the drive, and that’s it’s anISO 9660 disc. You can’t mount an audio CD.

• With the CDROM in the drive and unmounted, try something like:

  cat /dev/cdrom | od | more

  If you see a dump, then the drive and driver are probably workingOK, and the problem is at the filesystem level (i.e., the CDROM isnot ISO 9660 or has errors in the filesystem structure).

• If you seenot a block device errors, check that the definitionsof the device special files are correct. They should be asfollows:

  brw-rw----   1 root     disk       3,   0 Nov 11 18:48 /dev/hdabrw-rw----   1 root     disk       3,  64 Nov 11 18:48 /dev/hdbbrw-rw----   1 root     disk      22,   0 Nov 11 18:48 /dev/hdcbrw-rw----   1 root     disk      22,  64 Nov 11 18:48 /dev/hdd

  Some early Slackware releases had these defined incorrectly. Ifthese are wrong, you can remake them by running the scriptscripts/MAKEDEV.ide. (You may have to make it executablewith chmod first.)

  If you have a /dev/cdrom symbolic link, check that it is pointingto the correct device file.

  If you hear people talking of the deviceshd1a andhd1b, thesewere old names for what are now called hdc and hdd. Those namesshould be considered obsolete.

• If mount is complaining that the iso9660 filesystem is notavailable, but you know it is (check /proc/filesystems), youprobably need a newer version of mount. Early versions would notalways give meaningful error messages.

5. Directory listings are unpredictably truncated, anddmesg showsbuffer botch error messages from the driver.

• There was a bug in the version of the driver in 1.2.x kernelswhich could cause this. It was fixed in 1.3.0. If you can’tupgrade, you can probably work around the problem by specifying ablocksize of 2048 when mounting. (Note that you won’t be able todirectly execute binaries off the CDROM in that case.)

  If you see this in kernels later than 1.3.0, please report it as abug.

6. Data corruption.

• Random data corruption was occasionally observed with the HitachiCDR-7730 CDROM. If you experience data corruption, using “hdx=slow”as a command line parameter may work around the problem, at theexpense of low system performance.

5. cdchange.c¶

/* * cdchange.c  [-v]  <device>  [<slot>] * * This loads a CDROM from a specified slot in a changer, and displays * information about the changer status.  The drive should be unmounted before * using this program. * * Changer information is displayed if either the -v flag is specified * or no slot was specified. * * Based on code originally from Gerhard Zuber <zuber@berlin.snafu.de>. * Changer status information, and rewrite for the new Uniform CDROM driver * interface by Erik Andersen <andersee@debian.org>. */#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <unistd.h>#include <fcntl.h>#include <sys/ioctl.h>#include <linux/cdrom.h>intmain (int argc, char **argv){      char *program;      char *device;      int fd;           /* file descriptor for CD-ROM device */      int status;       /* return status for system calls */      int verbose = 0;      int slot=-1, x_slot;      int total_slots_available;      program = argv[0];      ++argv;      --argc;      if (argc < 1 || argc > 3) {              fprintf (stderr, "usage: %s [-v] <device> [<slot>]\n",                       program);              fprintf (stderr, "       Slots are numbered 1 -- n.\n");              exit (1);      }     if (strcmp (argv[0], "-v") == 0) {              verbose = 1;              ++argv;              --argc;      }      device = argv[0];      if (argc == 2)              slot = atoi (argv[1]) - 1;      /* open device */      fd = open(device, O_RDONLY | O_NONBLOCK);      if (fd < 0) {              fprintf (stderr, "%s: open failed for `%s`: %s\n",                       program, device, strerror (errno));              exit (1);      }      /* Check CD player status */      total_slots_available = ioctl (fd, CDROM_CHANGER_NSLOTS);      if (total_slots_available <= 1 ) {              fprintf (stderr, "%s: Device `%s` is not an ATAPI "                      "compliant CD changer.\n", program, device);              exit (1);      }      if (slot >= 0) {              if (slot >= total_slots_available) {                      fprintf (stderr, "Bad slot number.  "                               "Should be 1 -- %d.\n",                               total_slots_available);                      exit (1);              }              /* load */              slot=ioctl (fd, CDROM_SELECT_DISC, slot);              if (slot<0) {                      fflush(stdout);                              perror ("CDROM_SELECT_DISC ");                      exit(1);              }      }      if (slot < 0 || verbose) {              status=ioctl (fd, CDROM_SELECT_DISC, CDSL_CURRENT);              if (status<0) {                      fflush(stdout);                      perror (" CDROM_SELECT_DISC");                      exit(1);              }              slot=status;              printf ("Current slot: %d\n", slot+1);              printf ("Total slots available: %d\n",                      total_slots_available);              printf ("Drive status: ");              status = ioctl (fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);              if (status<0) {                perror(" CDROM_DRIVE_STATUS");              } else switch(status) {              case CDS_DISC_OK:                      printf ("Ready.\n");                      break;              case CDS_TRAY_OPEN:                      printf ("Tray Open.\n");                      break;              case CDS_DRIVE_NOT_READY:                      printf ("Drive Not Ready.\n");                      break;              default:                      printf ("This Should not happen!\n");                      break;              }              for (x_slot=0; x_slot<total_slots_available; x_slot++) {                      printf ("Slot %2d: ", x_slot+1);                      status = ioctl (fd, CDROM_DRIVE_STATUS, x_slot);                      if (status<0) {                           perror(" CDROM_DRIVE_STATUS");                      } else switch(status) {                      case CDS_DISC_OK:                              printf ("Disc present.");                              break;                      case CDS_NO_DISC:                              printf ("Empty slot.");                              break;                      case CDS_TRAY_OPEN:                              printf ("CD-ROM tray open.\n");                              break;                      case CDS_DRIVE_NOT_READY:                              printf ("CD-ROM drive not ready.\n");                              break;                      case CDS_NO_INFO:                              printf ("No Information available.");                              break;                      default:                              printf ("This Should not happen!\n");                              break;                      }                if (slot == x_slot) {                status = ioctl (fd, CDROM_DISC_STATUS);                if (status<0) {                      perror(" CDROM_DISC_STATUS");                }                switch (status) {                      case CDS_AUDIO:                              printf ("\tAudio disc.\t");                              break;                      case CDS_DATA_1:                      case CDS_DATA_2:                              printf ("\tData disc type %d.\t", status-CDS_DATA_1+1);                              break;                      case CDS_XA_2_1:                      case CDS_XA_2_2:                              printf ("\tXA data disc type %d.\t", status-CDS_XA_2_1+1);                              break;                      default:                              printf ("\tUnknown disc type 0x%x!\t", status);                              break;                      }                      }                      status = ioctl (fd, CDROM_MEDIA_CHANGED, x_slot);                      if (status<0) {                              perror(" CDROM_MEDIA_CHANGED");                      }                      switch (status) {                      case 1:                              printf ("Changed.\n");                              break;                      default:                              printf ("\n");                              break;                      }              }      }      /* close device */      status = close (fd);      if (status != 0) {              fprintf (stderr, "%s: close failed for `%s`: %s\n",                       program, device, strerror (errno));              exit (1);      }      exit (0);}