Re: Compact Flash performance...

[Willy Tarreau]

On Thu, May 31, 2007 at 06:43:46PM -0400, Mark Lord wrote:
> Jeff Garzik wrote:
> >Mark Lord wrote:
> >>Some cards may perform better when their "memory" interface is used
> >>instead of the "I/O" interface, or vice-versa.  I'm not sure which
> >>of the two methods was selected by libata (probably the "memory" 
> >>interface).
> >
> >I am very CF-ignorant.  How does libata select a memory or I/O interface 
> >on a CF device?
> 
> Right.  Usually we cannot select them, as it's the wires between
> the ATA chipset (motherboard) and the CFCARD that determine this.

CF cards support 3 modes (MEM, I/O and True IDE), and neither MEM nor I/O
modes can talk IDE. Most often, the PIN 9 is simply shorted to the ground
at the connector to set the card in True IDE mode, which makes it emulate
a standard IDE disk.

Cheers,
Willy

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