[Leaplist] External eSATA/USB to 2.5"/3.5" SATA/SAS "dock" ...

[Bryan J. Smith]

On Sat, 2/13/10, Damien McKenna <damien at mc-kenna.com> wrote:
> I might have missed something, but why?

On Sat, 2/13/10, Kevin Korb <kmk at sanitarium.net> wrote:
> Yeah.  I have never used or had a need for ESATA
> myself but my understanding is that it is just a SATA
> port for external use.  It should be much faster than
> USB and with the specs of SATA.  Is there a problem I
> have not heard about?

Just lack of specifications, certification, mechanical standards
in cabling, etc...

SATA can go up to 1m.  A few vendors got together and decided to
make a connector for external, add some sort of unspecified
shielding and claim up to 2m lengths, calling it eSATA.  Now
there has been really no formalized recommendations on number of
adapters, EMF/EMI considerations, etc...  Also, it's only
supposed to be 0.5m for SATA/3G and 1m for eSATA/3G, although
most vendors don't mention that either.

End result:  Every single eSATA experience I've had has been a
mess of incorrect cable-to-device mechanical specifications,
high error rates and countless other issues.

I honestly gave up after I inquired Seagate several times for a
"certified cable" for their FreeAgent Pro devices (since they
didn't include one).  Both of my FreeAgent Pro drives have failed
since, so I haven't bothered to try again.  I've run into two
other people trying to use eSATA enclosures and they too had
major issues.

I've had no issue with SAS, but SAS uses twisted pair and other
cabling that allows 8m lengths.  The SAS specification was
designed for external from the get-go, right down to standards
and tested implementations, multi-channel and multi-target, etc...
Of course, SAS is far more expensive and far less commodity logic
(even when the drive implementations themselves are only commodity
5400-7200rpm).

Maybe SATA/6G will solve things, as I understand it's supposed to
adopt twisted pair and other things as standard.  We'll see.  It
will also be interesting to see how USB 3.0 competes.


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