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  1. Agustin's Linux Manual
  2. Multimedia & Hardware Installation
  3. About the Author
  4. Contents
  5. Multimedia
  6. Default Audio Setting
  7. Audio Application
  8. The Play Directory
  9. The Equalizer
  10. Options Sub-menu
  11. Movies & DVDs
  12. Starting Xine
  13. Video Conferencing
  14. GnomeMeeting's Main Window
  15. The Desktop
  16. Office
  17. Networking
  18. Multimedia Submenu
  19. Web Browsers
  20. Installing New Hardware
  21. Loading Modules for Hardware
  22. Introduction to IDEs
  23. Tweaking the Hard Drive
  24. Setting (U) DMA
  25. Installing a CD/RW
  26. Floppy Disk, Zip Drives
  27. Installing USB Devices
  28. Fire wire IEEE 1394
  29. Using the CD-Writer

Setting (U) DMA

To set DMA mode, the following command is used, the command itself can be used but a combination of X is preferred to ensure that the drive itself is programmed. Read the drive documentation before trying this.

       hdparm -d1 /dev/hda

hdparm -d1 X mdma2 /dev/hda    //setting xfermode (multiword DMA Mode 2)
  • X sdma1 is used to set simple mode DMA transfer
  • -X mdma2 is used to set multiword DMA mode 2
  • -X udma2 is used to set ultra DMA mode 2 transfer (you need to prepare the chipset first)

Note. The X is used to set transfer mode for newer drive (E)IDE use it only when the chipset supports it. Query the setting first before you make changes. New drives may already turn on this PIO modes at power on.

Always query and benchmark the drive after your settings, to ensure that the drive has been programmed the way you want it.

Note. All modifications or setting are not saved permanently. If you reboot the system, the settings are lost. So when you do this make note of the settings, create a file and execute it via bash script, or via /etc/rc.d/ alternatively and probably best, add the line in your /etc/rc.d/rc.local

Installing CD-ROMs

All CD-ROMs, CD Writers, DVDs and IDE ZIPs drives are treated as SCSI devices under Linux. Most CD-ROMs are detected automatically, especially if you are installing Linux from CD-ROMs, when you finish the installation the Drive should be already working.

Make note that even the CD-ROM is configured properly; it may not be available when you need it. A CD-ROM, in order to be accessible needs to be mounted. To find out about the real name of your device type this:

  • ls -l /dev/cdrom
  • dmesg | grep CD

To mount the CD-ROM, use these commands:

  • mount /dev/cdrom /mnt/cdrom
  • mount /dev/scd0 /mnt/cdrom
  • mount /dev/scd1 /mnt/cdrom


  • mount /dev/hdb /mnt/cdrom

Where /mnt/cdrom is a directory to temporarily, read the information contained in your physical CD-ROM. /dev/xxx is your physical device.

Some times you need to eject a CD from the CD-ROM drive, but the drive won't open, it is because it is mounted. In order to remove the CD you have to un-mount the drive first. To un-mount the drive, use this:

  • umount /mnt/cdrom

Note. Mount and umount is executed as root.