The receptacle key slots will mean:
a) no key slots: SAS-1 phy present, only <= 6 m passive
cables supported
b) key slot 1: SAS-2 phy present, > 6 m passive cables
supported
c) key slot 2: power provided. A SAS-2 phy is
probably present, but that's orthogonal.
A SAS-1.x receptacle includes no key
slots.
A SAS-2.x receptacle not providing power will just include
key slot 1.
A SAS-2.1 receptacle providing power will include
both key slots 1 and 2.
The cable keys will mean:
a) none: <= 6 m passive cable
b) key 1: > 6 m passive cable, needs a SAS-2
phy
c) key 2: active cable, needs power
This ensures that:
1. short passive cables plug in
everywhere
2. long passive cables only plug into receptacles with
SAS-2 phys
3. active cables only plug into receptacles with
power
It's up to the
power supply logic behind a receptacle with key slot 2 to determine if the cable
is passive or active and only provide power to an active cable.
(NOTE: the numbers of the key positions may change... e.g.,
these might be slots "1" and "5" in the end)
---
Rob Elliott, HP Industry Standard Server
Storage
During our last SAS phy conference
call, there were separate keys indicated for active cables (see 08-257r0). I am
wondering what the implementation plan is. The keys provide no protection from
plugging in a SAS 1.1 (legacy passive) cable and the phy's should work with the
SAS 2.0 10-meter passive version, so what is the advantage of adding this key? I
guess I am missing something in the planned implementation. Could someone
elaborate?
Alvin Cox
Seagate
Technology, LLC
Office 405-381-8067
Cell 405-206-4809
E-Mail
alvin.cox@seagate.com