SCSI Emulation w/ DMA

Hi everyone,

I have SCSI emulation on my CDR drive in order to burn and the like, but I was confused by the following entries in /var/log/messages...

----------------------------------------------------------------------

Aug  5 12:18:48 localhost kernel: SCSI subsystem driver Revision: 1.00
Aug  5 12:18:19 localhost rc.sysinit: Setting clock  (localtime): Mon
Aug  5 12:18:13 UTC 2002 succeeded
Aug  5 12:18:49 localhost kernel: scsi0 : SCSI host adapter emulation
for IDE ATAPI devices
Aug  5 12:18:19 localhost rc.sysinit: Loading default keymap succeeded
Aug  5 12:18:49 localhost kernel:   Vendor: LITE-ON   Model: LTR-24102B
        Rev: 5S0J
Aug  5 12:18:19 localhost rc.sysinit: Setting default font (lat0-sun16):
  succeeded
Aug  5 12:18:49 localhost kernel:   Type:   CD-ROM        ANSI SCSI
revision: 02
Aug  5 12:18:19 localhost rc.sysinit: Activating swap partitions:  succeeded
Aug  5 12:18:49 localhost kernel: hdc: DMA disabled

-----------------------------------------------------------------------

The last line says that DMA is disabled, but it refers to hdc. Since my /dev/cdrom is linked to /dev/scd0, and /dev/cdrecorder is linked to /dev/sg0, does that mean DMA is working anyhow? How can I tell?

(I was prompted into peeking around after burning seemed a little slow..)

Thanks in advance,
Dave.

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Even though you have scsi emulation enabled, there is an ide driver hidden in the demimonde of your system that the scsi emulator communicates through. It is the ide driver, the part that actually talks to the hardware, that either has DMA on or off.

Almost surely, the message you are seeing means that DMA is off. To check it, run "hdparm /dev/hdc" and see that the resulting report says about DMA. If you want to turn it on, run (as root) "hdparm -d 1 /dev/hdc". If you always want it on, add that line to one of the system's init scripts (probably whatever corresponds to rclocal on your system).

Now I am not at all sure about this next part ... but I doubt that the DMA setting is what is making your CD burns slow. How are you burning (what is the actual command-line string you send)? What speed is your drive? How long is it taking to burn (your "a little slow" could be someone else's "fast")? What are you burning (iso images? copies of music CDs? VCDs?)

--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski -- Han Solo
Palo Alto, California, USA [email protected]
-------------------------------------------------------------------------------

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Hello all:

I've got a notebook that I will be hooking an external display to from time to time. Of course the external display has totally different settings than the notebook's native display (native display is limited to 800x600 res, for example). For this reason, I'd like to be able to start X with one of 2 differing XF86Config files, depending on whether I'll be using the notebook's own monitor or the external one. I've got working XF86Config files for both the external and native displays. What I'm having some trouble with is figuring out how to invoke one or the other XF86Config file when I start X. Any suggestions on how to go about this?

Thanks, James

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Never needed to do this myself, but the man page for "XF86Config" says you can specify an alternate file with the "-xf86config" argument on the command line. The man page is a bit unclear as to what command it associates this aggument with, and you don't say how you are starting X anyway ... but I'd *try* passing it as a server argument to startx ("startx -- -xf86config appropriate_file_name") and seeing it that did the trick.

If that's not quite it, perhaps this is enough of a start that you can use the man system to track down the right way to pass this argument yourself.

--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski -- Han Solo
Palo Alto, California, USA [email protected]
-------------------------------------------------------------------------------

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

don't know if this is considered a "bad approach", but another way to do this is to simply name your working XF86Config files appropriately and then just create a symlink to whichever file it is your using.

matthias

the

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Hmmm. This I don't understand. What would be the purpose of symlinking, and from where (i.e., what point in the Linux startup process) would the symlink get used? Are you talking about creating a symlink pointing to the desired XF86Config and calling it "XF86Config" each time I am preparing to start X? I can see how that would work, but it seems about the same amount of time and trouble as renaming XF86Configs each time I wish to start X. I guess I'm looking for a more elegant and less time-consuming solution. So far, Ray's looks best.

Thanks, James

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Use your imaganation, create a script, call it what you want, i will call it GoX

#!/bin/sh

case "$1" in

1)

	/bin/ln -s /etc/X11/XF86Config-1 /etc/X11/XF86Config
	/usr/X11R6/bin/startx
	;;
  2)
	/bin/ln -s /etc/X11/XF86Config-2 /etc/X11/XF86Config
	/usr/X11R6/bin/startx
	;;

*)
/bin/echo "USAGE: GoX 1 or GoX 2 "
esac

#------------------------------

No use the command;
'chmod a+x GoX'
To make it executable.

Its all so easy...

Regards Richard
[email protected]
http://people.zeelandnet.nl/pa3gcu/

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Ray:

Thanks for your answer. I'm starting X from the cli - "startx". Is there some other way it could be started, offering a choice of XF86Configs?

James

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Not that I know of. I already suggested a cli method of selecting the config file when running X via startx, and someone sles suggested the alternative of using symlinks and changing the symlink depending on what display you are using. I suppose you could write a wrapper program for startx (or even modify startx to do this; startx is just a bash script that calls xinit) that asked you what file you wanted to use, then passed on the appropriate command-line argument.

I was mainly trying to make sure you were not starting X with xdm. I don't know how one would pass command-line arguments with xdm, since there is no command line in that case.

--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski -- Han Solo
Palo Alto, California, USA [email protected]
-------------------------------------------------------------------------------

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

Thanks for the help Ray...

To answer your questions:
I'm using a Plextor 24X with the command, 'cdrdao write toc.file', and I'm burning a mix of isos and music cds.
Under Windows, this process never seemed to take more than three and a half minutes, but with Linux, average burn times hover around four and change. Now I know, thirty seconds isn't much to whine over, but I was just curious to see if it was something I had failed to do. I read both the CD-ROM HOW-TO, and the CD-Writing HOW-TO, but I must have missed the illuminating section.

More interestingly, the burner I have at work is a generic Lite-On 24/10/40, and it usually takes anywhere from 8-10 minutes to burn a cd, under both Windows and Linux. I never gave it much thought, however, because hey I'm at work, and I might as well take the opportunity to grab a coffee and a cigarette.

Dave.

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs

I'm not sure what would qualify here as "illuminating". I don't use cdrdao myself (I use cdrecord), but in my CD burnings, I notice two things that might be relevant:

1. cdrecord waits about 10 seconds before it starts burning, with a countdown on the screen, to give me an option to abort the burn.

2. I too have a 24x burner (a Sony), and I tell this to cdrecord. Nonetheless, it always tells me that it is burning (iso images) at 12x, not 24x.

Since the discrepancies you are seeing between Windows and Linux are so small, they are probably the result of some subtlety in the way the two apps work (possibly including what each does before and after you start the clock -- with differences that small, asking how exact your timings are is a reasonable thing to do). I mentioned those two not to diagnose your situation, but as examples of the kinds of things that might be going on. either in your home setting or in the work one you describe below.

[rest deleted]

--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski -- Han Solo
Palo Alto, California, USA [email protected]
-------------------------------------------------------------------------------

-
To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.linux-learn.org/faqs