Re: [PATCH] speed up SATA

[Stefan Smietanowski <stesmi@stesmi.com>]

Hi Jeff.

>> What will happen when a PATA disk lies behind a Marvel(ous) bridge, as
>> in most SATA disks today?
> 
> Larger transfers work fine in PATA, too.

Correct me if I'm wrong but wasn't the max number of sectors in a
transfer limited to 255 instead of 256 because there were buggy
drives out there before ? I seem to recall something like that but
I could be wrong.

Of course I hope nobody in his right mind would take those old things,
slap a Marvel chip on it and sell it as new :) But someone else could
buy one of those SATA<->PATA converter cables with a Marvel on it and
run it with the old disk <shudder>. Wouldn't those cases bug out?

>> Is large transfers mandatory in the LBA48 spec and is LBA48 really
>> mandatory in SATA?
> 
> Yes and no, in that order :)  SATA doesn't mandate lba48, but it is 
> highly unlikely that you will see SATA disk without lba48.

Naturally, see my comment above regarding SATA<->PATA converter cables.

> Regardless, libata supports what the drive supports.  Older disks still 
> work just fine.

Or.. should :)

// Stefan