CD Rom Drive too slow? September 20, 2005Posted by Carthik in administration, commands, ubuntu.
If your CR Rom drive, or the CD-RW drive, or your DVD reader/writer are slower than their stated speeds for reading or writing (burning), then you may not have DMA (Direct Memory Access) enabled on the drive in question. DMA allows for faster data access for drives that support it by effectively not using CPU time for data transfer to put it really simply.
You can check if the cd drive has the option enabled by doing a:
$sudo hdparm /dev/hdc
Where “hdc” stands for the drive in question – change this if it is different on your machine (you can find out by looking in the /etc/fstab file)
If it says “dma = 0” in the output of the command, then that means that dma is currently disabled for the drive.
You can enable it temporarily for the current session till you shutdown the computer by using the command:
$sudo hdparm -d1 /dev/hdc
This will be reset when you reboot. You can make the change more permanent by editing the file /etc/hdparm.conf, and adding the following to the end of the file:
dma = on
This will turn on dma each time you boot up the computer.
Also, if you cd/dvd writer provides for some form of buffer under-run protection, you can enable nautilus to use this when it writes to the disc by using the “burnfree” option. You can set this option by doing :
$gconftool-2 –set –type boolean /apps/nautilus-cd-burner/burnproof true
Note: Your system BIOS also gets to decide how your drives behave, so check to see if the proper options are enabled in the BIOS upon boot-up.
There! Now you should be able to read/write from optical drives at the best possible speed.