Thanks for the info, it is deffinanlty good to know.  I really did wonder
why my old 20 gig IDE that I have clunking around shows up as sdd, and now I
know.  :)

On 1/11/08, Alberto Treviño <[EMAIL PROTECTED]> wrote:
>
> On Thursday 10 January 2008 09:37:08 pm Robert LeBlanc wrote:
> > As Michael said, SCSI has supported hot-swap for year, so has fibre
> > channel. SATA gets sticky because some manufactures use ATA type
> > commands and controller technologies and some use SCSI. A few years
> > ago, some SATA drives showed up as /dev/hd* and some showed up as
> > /dev/sd*. I found this out the hard way when we went to install ESX
> > Server on a SATA drive and it did not show up as /dev/sd*. ESX
> > requires SCSI or FC drives (version 2.5). I think for the most part
> > they show up as SCSI now for both types of implementations.
>
> This really depends the BIOS settings, the kernel, and therefore the
> distribution.  Let me explain.
>
> Some older BIOSes allowed for the IDE emulation of SATA.  That means the
> SATA controller and the drives would appear from a system standpoint as
> IDE drives for compatibility with non-SATA-enabled OS's.
>
> In the Linux kernel, SATA was built upon the SCSI framework because of
> its many similarities.  Hence, any SATA drives that used the correct
> SATA driver (rather than IDE) would show up as /dev/sd*.
>
> In the last little while (and I'm too lazy to look it up), the SATA
> subsystem in the kernel was expanded to deal with PATA (parallel ATA or
> IDE) as well as SATA, often in the same driver (as is the case with
> several Intel chipsets).  What that translates to is having *all* hard
> drives and CD drives appear as SCSI devices, even old IDE drives.  This
> is where distributions come in.  Distributions have the choice of using
> the old legacy IDE subsystem (/dev/hd*) or selecting the newer
> SATA/PATA subsystem (/dev/sd*).
>
> Anyway, sorry for the history lesson, but I think sometimes it is good
> to know what is going on and the context on which it goes on. :-)
>
> --
> Alberto Treviño
> [EMAIL PROTECTED]
> Testing Center
> Brigham Young University
> --------------------
> BYU Unix Users Group
> http://uug.byu.edu/
>
> The opinions expressed in this message are the responsibility of their
> author.  They are not endorsed by BYU, the BYU CS Department or BYU-UUG.
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>



-- 
Jordan Taylor
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