why my Slave ATAPI IDE CDROM recognized as /dev/scd0
 

hi
why my Slave ATAPI IDE CDROM recognized as /dev/scd0
how I can check how it is working ? how to peed up it? because Hdparm does not work with it
thanks

It's recognized as scd0 because some distributions of Linux turn on scsi emulation support for any ATAPI device. To see if its working type "cdrecord -scanbus" and you should see your cdrom on the first line. You could then try to play music cds by pointing the media player at /dev/scd0. Hdparm is for tweaking and testing hard drive performance.

yes it is in the list
it is working fine howether I was under impression that hdparm working with any IDE devices for exaple it should be able tochange DMA mode of CDrom or DVD and other option as well... and I did change somesetting on my DVD. so is it possible to make this cdrom whichis now /dev/scd0 something like /dev/hdd?

Aha, I track down this post from the linux-general, let's see - do you have a CD-burner on your system?

yes I this cd rom is a liteon burner

That's why, linux requires the burner to be a SCSI device to work as a burner, so smart ppl came up with idea to fool linux system to think that your ATAPI IDE cd-r/rw is a SCSI device, it is done thru ide-scsi emulation.

is there any way to check in what mode it is working what DMA etc? and maybe change it?

is it a primary slave? then run /sbin/hdparm -I /dev/hdb
if it is supports mdma or sdma then you can turn it on if it isn't on already with
/sbin/hdparm -d1 /dev/hdb you must be root to accomplish this task

hi thaks so much. you are right. even curently my liteon is working as /dev/scd0 it is also can be accesssed as /dev/hdd as a secondary slave and so speedup as /dev/hdd
thans

Interesting thread - I was looking for answers to exactly the same question as Alexop.

I'm very new to Linux too. I ran the hdparm command as suggested and noted, amongst other things, DMA settings of "sdma0 sdma1 sdma2 mdma0 mdma1 *mdma2".

Q1) I'm presuming that the * indicates that DMA is enabled on the device?

Like Alexop the hardware is listed as (within KDE Control Module):
PCRW804
/dev/hdd
configured=Y, available=N, needed=N
Philips PCRW804
/dev/sr0
configured=N, available=Y, needed=N

I only installed last night so haven't checked the functionality of everything but I can mount and view CDs (haven't tried burning or playing music though)

Q2) Should I be overly concerned, if at all, with these settings? KDE Control Module shows hdd with a red cross next to it and sr0 with a spanner?

Q3/4) When Alexop referred to using it as hdd is there a choice of how to mount it? Do I have a reason to care?

thanks