[Gllug] re: SCSI vs SATA

[Richard Jones]

On Wed, Jun 09, 2004 at 10:47:47AM +0100, t.clarke wrote:
> One thing that always puzzles me is why SCSI isn't inherently at least 8/16
> times faster than SATA, bearing in mind that the data is transferred on SCSI
> over more wires in parallel than SATA (as I understand it !).
> 
> Can anyone explain/point to an explanation ?

In very very hand-waving terms, if you have lots of wires, you need to
make sure the signals arrive simultaneously at the other end of the
cable.  If they might not arrive at the same time, then you need long
setup and hold times at the receiving end, and that slows you down.

Of course the real benefit is cost: to run parallel cables at any
speed you actually need a separate return path for each wire => huge
inflexible expensive cables.  Serial can get away with 2 (?) wires at
a much much lower cost.

Rich.

-- 
Richard Jones. http://www.annexia.org/ http://www.j-london.com/
Merjis Ltd. http://www.merjis.com/ - improving website return on investment
MONOLITH is an advanced framework for writing web applications in C, easier
than using Perl & Java, much faster and smaller, reusable widget-based arch,
database-backed, discussion, chat, calendaring:
http://www.annexia.org/freeware/monolith/
-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug