Re: [Dvdrtools-users] Re: [Fwd: Re: Is my MSI DR8-A2 broken?]

[Svante Signell]

On Tue, 2006-01-03 at 08:24 -0800, Bryan J. Smith wrote:
> Svante Signell <address@hidden> wrote:
> > No I did not, The file size is 4685914112 bytes which is
> > less than 4.7 GB. 
> 
> Is that the size of the ISO file?
> Or is that the size cdrecord reports?

In fact the file size given was with a DVD structure on the hard disk
and the size was given by du -sb dir_name. I don't have the .iso file
saved any longer, but it was created from the same file structure as
above, with mkisofs -dvd-video -o file.img. I did manage to burn this
image to a DVD+RW, but DVD+-R failed due to the broken MSI burner. 

> > Do you say that if I write a file located in /dev/hdc and
> > the writer is at /dev/hdd, i should disable DMA for both
> > drives?
> 
> Not exactly.
> 
> What I said was you should _never_ put DMA devices in a
> master/slave relationship, but 1 device per channel.

The drive can only be mounted with Master/Slave straps set or in Cable
Select. Are you proposing Cable Select here?? I don't think so!

> > This would then apply to all burners installed in PC, Linux
> > Windows, etc computers.
> 
> Yes!  ATA in DMA mode means the Integrated Drive Electronics
> (IDE) of the drive is talking directly to the system memory. 
> That's why you should _never_ have more than 1 device per
> channel.  Because it requires a major change in the bus
> operation, which often results in bus resets.
> 
> > What about the case of copying files from one hard disk to
> > another, for example /dev/hda to /dev/hdb? In that case the
> > file transfers should never finish.
> 
> Huh?  How did you get that logic?  I never even suggested
> such.
> 
> /dev/hda takes control of the bus, negotitates DMA and writes
> to memory.  /dev/hdb then takes control of the bus,
> negotiates DMA and reads from memory.  Just because the
> operation requires a major context switch and cannot occur
> simultaneously doesn't mean it doesn't finish.
> 
> It just doesn't happen simultaneously.  If you have a
> real-time process like DVD recording, then that's a serious
> issue.
> 

Can you explain the difference with file transfer between /dev/hda
and /dev/hdb using DMA with writing a file on /dev/hdc to a burner
at /dev/hdd using DMA then!  

Thanks,
-- 
Svante Signell <address@hidden>