Re: SAS overview

[Jeff Garzik <jgarzik@pobox.com>]

Scott M. Ferris wrote:
> For the fast path of queueing and completing commands, I'd expect SAS
> HBAs to work similar to SPI HBAs, where all the HBA driver does is
> queue commands with data buffers, and wait for an interrupt to
> indicate that one or more commands have completed.  For performance,
> the HBA needs to manage the entire lifetime of the command, and DMA
> data back and forth without needing intervention by the HBA driver.

Newer SATA controllers do this for you, but still give you low level 
access to the individual frames being sent on the SATA wire...

	Jeff