Archived from groups: alt.comp.periphs.mainboard.supermicro (
More info?)
I know just what you mean. I built my current "main system" that I use in
my house around Supermicro's P8SAA Mobo and their SC742T-550 chassis. This
chassis has 7 SATA HDD blade slots, and I'm using 6 of them. I've only
gotten partial success in getting the LED lights to properly indicate drive
activity. I e-mailed SM while I was laying out the system and already had
the chassis, but nothing else at that time. I asked them about the "pair"
of 5 conductor ribbon cables that were attached to the SATA backplane. Also
note that there are 10 conductors on this Ribbon cable coming from the
backplane, but only 7 SATA blade slots!
Here's what I send:
Dear Supermicro,
Within the last few weeks I made a purchase of your SC742T-550 Chassis. I
must say that the materials, construction, and design of this case are
second to none. However, like so many other computer cases that I have had
to deal with, the documentation is sorely lacking. I'm left to figure most
things out my “looking” or relying on past experience. I'm surprised that
Supermicro would take such an approach to their products.
In this instance my problem is lack of documentation on the included
“CSE-SATA-742” Backplane. My question is just what does the ½” Wide, ten
conductor ribbon cable, with twin five-conductor plugs marked, “1-4,C” &
“5-8,K”, that is connected to the Backplane, do? Where does “it go”? I could
try a plug-and-pray approach, but that is a bit too unprofessional and
dangerous to the electronics. I suspect that it’s related to “Drive
Activity”, but that is just a guess. Please could you help on this question?
I'm hoping that it is not totally proprietary, and of use only on specific
SM Motherboards. Written info on this Backplane would be wonderful. I've
looked everywhere on your web site without any reference to said item.
Perhaps the single most important reason I purchased this Chassis to begin
with was the included 7-SATA bays. I plan to build a personal workstation
containing from between five to seven SATA HDD’s. A perfect match to this
Chassis, if I say so myself.
Here is their response:
Hi,
Yes, the C, 1, 2, 4, 5 and K, 6, 7, 8, 9 are SATA Activity low voltage LED
signal support. The cable must connect to PCI SATA IDE raid controller or
on-board IDE SATA raid controller.
C= Common.
1= Activity LED 1
2= Activity LED 2
3= Activity LED 3
4= Activity LED 4
5= Activity LED 5
K= Key
6= Activity LED 6
7= Activity LED 7
8= Activity LED 8
9= Activity LED 9
The C= Common and K= Key are not use.
Thank you,
DL
Well...that helped some, but it still didn't lay out a map between the SATA
drive (or Blade Number) on the backplane and the exact cable number.
Something tells me they really don't know or worse yet, even care. (NOTE
that the numbers DL listed in his/her response are incorrect. The ribbons
are c/1-thru-4 and k/5-thru-8. There is no "9" on the SC742T-550. Also
there are only 7 drives so where does 8 go?) So here is what I did.
I purchased a "Promise FastTrack S150 SX4 " RAID 5 PCI controller card and
placed it in one of the PCI slots (closest to the PCI-X slots). Now this
controller card has a "set" of 4 pins that are precisely spaced to plug into
one(1) of the ribbon cables coming from the backplane. I used LED numbers 5
thru 8 for these four pins on the Promise card. Works great except that LED
lights "4,5,&6" (they're the top 3) now light up on the front of the chassis
whenever there is any I/O to the RAID system. Why 3 and not 4...I really
don't know. Also this will trigger the drive LED located across the top of
the Chassis.
The Ribbon with numbers C/4, I connected to the P8SAA Mobo. It also has a
four(4) pin output for its own built in SATA controller. With a magnifying
glass I was able to see which pin was labeled "1" and plugged in the Ribbon
cable using only numbers 1-4. Now whenever and one of the drives in blades
0,1,or 2 has I/O all three LEDs light up (they're the bottom 3 on the
chassis). Interesting!
This is where I sit. I can tell RAID activity from System drive activity,
but that's about it. A bit of a let down from when I first obtained the
Chassis. Still I think the SC742T-550 (or the new -650 model) is without a
doubt the finest computer desktop chassis on the market today. Oh, in
summary...I have 4 120GB SATA HDDs in blades 4,5,6, & 7 connected to the
Promise Controller. I have three SATA HDDs in blades 0,1, & 2 connected to
the Mobo (with 0 being the System drive). The Chassis blades are numbered
from 0 to 6 from the bottom up.
Hope this helps some. I know when sometimes the numbering system starts
with "0" and sometimes with "1" can get confusing. I didn't invent the
system!
DER
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