Friday afternoon hardware questions

[Ben Scott]

On Jan 23, 2008 6:07 PM, Bill McGonigle <bill at bfccomputing.com> wrote:
>> I've also heard of multiport(path?) where 1 SATA port goes to 4-5 devices.
>
> Yeah, like Jarod said, this is just 4x4 (e.)SATA.

  Perhaps not.  From what I've read, there is a standard way to
connect multiple logical devices in a single SATA cable.  This
facilitates a device called a "SATA port multiplier".  You have run a
single (e)SATA cable from the host adapter to the port multiplier.
The multiplier offers physical connections to some number of drives,
and has silicon to multiplex the drives into the single SATA cable.
So run one eSATA cable out of your computer and into the external
enclosure, and put a port multiplier in the enclosure.  This isn't a
performance problem, because 3 gigabit/sec is still *way* faster than
any physical disk can serve up.  Google found a good page:

http://www.sata-io.org/portmultiplier.asp

  It says you can put up to 15 logical devices in one SATA cable.

  All that said, it wouldn't surprise me if the
silicon/firmware/drivers for some SATA host adapters don't implement
that standard.  (Drives don't care; they just see a single device
connection to the port multiplier.)

  SATA really has far more in common with SCSI than the ATA of old.
In effect, SCSI won the "IDE vs SCSI" war by marketing.  "People won't
accept SCSI?  No problem; we'll just call it 'SATA' and everybody will
be happy."  ;-)

-- Ben