Re: PATA-disk named sda

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Friday 06 July 2007, Mark Lord wrote:
> Robert Hancock wrote:
> >..
> > Currently the DMA, multi-sector mode, etc. are not controllable with 
> > hdparm with libata. libata is designed to use the fastest settings 
> > possible by default. In a lot of cases this messing with hdparm was only 
> > needed because of stupidity with the old IDE code (like DMA not being 
> > automatically enabled if the low-level driver was built modular).
> 
> Actually, most of the hdparm flags were put there to help test the IDE
> subsystem and to help debug the much stranger hardware it had to deal with.
> 
> "DMA off by default" was a Linus Torvalds request, to help ensure data safety
> with all of the weird and wonderful crap pre-standardization.

Exactly as Mark says.

I just want to add that "DMA off by default" hasn't been a case for a long
time now and since 2.6.21 the config option for "DMA on by default" is also
finally gone (to make a long story short: this was the best way to fix some
bugs while not causing regressions, not to mention that it was defaulting
to Y for years).

Thanks,
Bart