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Re: cdrecord freezes when burning data

On Sat, Feb 01, 2003 at 03:42:04AM +1100, bob parker wrote:
> On Sat, 1 Feb 2003 03:09, Ric Otte wrote:
> > Bob,
> >
> > I tried your suggestion, but it didn't work.
> > But then I got the idea to see if DMA affected it.  So I turned off DMA
> > by typing
> >
> > hdparm  hdparm -d0 /dev/hdc
> >
> > And I was able to burn a couple of data cds.  I reall don't know why
> > this worked (or even what DMA is), and I'm going to see if this
> > continues to work.  It puzzles me, because I believe DMA was on when the
> > cd burner was in my home machine.
> >
> > Thanks for the suggestion,
> >
> > Ric
> I know very little about DMA except that it's supposed to be faster when it 
> works. DMA is off on my machine and I have no freezes or other troubles but 
> my 24 speed burner can't maintain a burn speed > 12. 
> I tried stuffing around with hdparm to get a bit more speed the other night 
> and ended up frozen in kde and had to hit the Windows cure button ( hardware 
> reset ).
> Bob

DMA stands for Direct Memory Access. It means that data is transferred
directly between the drive and memory without the involvement of the

The alternative is PIO - Programmed I/O or something - in which (a)
the processor transfers the data to/from the drive, and (b) it does so
over the I/O bus, which runs at around 11MHz for historical reasons.
Hence, slow.

The common problem with DMA is that VIA chipsets, which are
distressingly common, have DMA bugs. It works OK on my machine, but
a lot of people have had problems. What chipset / MB have you got?


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