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

Alexop · 08-18-2002, 10:33 PM

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

darkmage · 08-18-2002, 10:54 PM

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.

Alexop · 08-18-2002, 11:22 PM

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?

neo77777 · 08-18-2002, 11:22 PM

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

Alexop · 08-18-2002, 11:25 PM

yes I this cd rom is a liteon burner

neo77777 · 08-18-2002, 11:28 PM

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.

Alexop · 08-18-2002, 11:31 PM

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

neo77777 · 08-19-2002, 01:34 AM

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

Alexop · 08-19-2002, 02:37 PM

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

AndyJ · 02-25-2003, 01:48 PM

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