On Tuesday, July 16, 2019 at 4:26:46 AM UTC-7, Paul wrote:
Robert in CA wrote:
I see what you mean by the 'L' now.... I'll
open the 780 up and have a look and take pics
but the OKGear Sata cable still only (1) HD
connection and we need (2).
Robert
Your motherboard has four SATA connectors total,
that I can see in a picture of the motherboard.
The data cables have a *one-to-one* relationship.
SATA1 --------------- HDD1
SATA2 --------------- HDD2
SATA3 --------------- Optical drive
SATA4 --------------- Optical drive
Therefore, we want a data cable with *one* connector
on each end.
Unlike the ribbon cable era, with two connectors on
the end of the ribbon, SATA has only *one*. It's point
to point, high speed serial. That's why the cable can
be thin.
*******
SATA does support FIS, which allows more than one
drive to be put on a single cable. The standard
supports up to 15 drives off one cable. The
silicon available for this, supports 5 drives
as a practical choice (from a bandwidth perspective).
The hardware is a small box, which would not be
a convenient formfactor for inside a PC.
Mobo SATA --------- FIS ------ SATA1
Box ------ SATA2
------ SATA3
------ SATA4
------ SATA5
The cables are *still* one-to-one. But the box
handles "fan-out". It allows a motherboard
with four SATA connectors, to support *20*
drives total.
I have yet to run into someone who has bought
one of those boxes. I think the boxes were
around $100 each when they were new.
This shows the printed circuit board of a
port multiplier. With the one chip that multiplexes
things. These only work with FIS-capable SATA ports
on other pieces of equipment. Not only do you
have to look up and see whether your computer
has that... but you also have to test that it
really works.
https://www.amazon.com/Misszhang-US-.../dp/B07NW7XD9Z
When Port Multipliers first came out, they were
packaged like this.
http://www.satacable.com/cosapomubrso.html
Paul
Oh, I get it now,.. here are some pics of the end
of the cable.
https://postimg.cc/Cz488RDY
https://postimg.cc/CzDgr8JT
https://postimg.cc/JHH55MNm
https://postimg.cc/5YTw0TZr
Robert