Messages in this thread | | | Date | Tue, 9 Apr 2002 11:32:06 +0200 (CEST) | From | Wojtek Pilorz <> | Subject | Re: PROMBLEM: CD burning at 16x uses excessive CPU, although DMA is enabled |
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On Tue, 9 Apr 2002, Anssi Saari wrote:
> Date: Tue, 9 Apr 2002 11:32:43 +0300 > From: Anssi Saari <as@sci.fi> > To: Mark Mielke <mark@mark.mielke.cc> > Cc: linux-kernel@vger.kernel.org > Subject: Re: PROMBLEM: CD burning at 16x uses excessive CPU, > although DMA is enabled > > On Mon, Apr 08, 2002 at 05:45:29PM -0400, Mark Mielke wrote: > > > The question is, how is CD burning of raw data different from > > CD burning of ISO images, in respect to Linux drivers for the > > hardware > > As far as I know, when burning an ISO image, the image has 2048 byte > sectors to which the CD writer adds error correction data so that the > individual sector becomes 2352 bytes. A raw data image includes 2352 byte > sectors. The obvious difference would be a higher data rate (2352/2048 > or 1.15x more) from computer to writer. > I have seen something similar when reading CD-Rs (with ISO image burnt); After I burn a CD I run readcd -c2scan to see if I get any C2 errors; I am using ASUS 50x CD drive, usually setting the speed to 45x before the operation (my TEAC CD-RW drive always run at 4x when doing readcd -c2scan, which is too slow for my patience).
The interesting thing is that while reading ISO image with dd the system works fine, readcd -c2scan makes it often very unresponsible (just switching between virtual desktops in KDE may take up to several seconds).
The system is Pentium III running at 720 MHz, ABIT RAID-133 motherboard, hard disk connected to HPT-370A, CD and CD-RW drived on separate channels, kernel 2.2.19 + IDE patches, 768 MB RAM.
I am wondering if you could possibly compare the system behaviour with Linux and FreeBSD when using readcd -c2scan (assuming readcd -c2scan works with your drives at some reasonable speeds).
Best regards,
Wojtek
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