15 Feb
2020
15 Feb
'20
12:35 a.m.
On 2/14/2020 11:11 PM, Alan Perry via cctech wrote:
The drives usually had two 60 pin IDC's one in front of the other. You'd
usually put a terminator for the daisy chain of the 60 pin bus cable in
the outer cable, and there was enough space between them to put the
ribbon cable.? They used braided cables most times I ever saw them.
The radial cable had a ground plane type ribbon cable with flat parallel
conductors composting the rest of the 26 pin cable.? Had to have one for
each drive from the controller to each drive.
I was going to suggest replacing the sun mess of cables with just one 60
pin cable and a 26 pin cable, and run with one drive, but realize you
probably only have the sun method of terminating the bus (60 pin)
cable.? it needs termination at the controller, and on the last drive.?
Since your system was set up with the sun connection and cabling, you
don't have a standalone SMD terminator, which is a small 60 pin thingie
that looks a lot lie the Single Ended SCSI terminator for the 50 pin
SCSI IDC cabling arrangement.
On 2/14/20 1:54 PM, jim stephens via cctech wrote:
They used the exact same name as the SMD drives you have.? But as you
say they are SAS, which are the somewhat older cousins of SATA drives,
and nothing to do with your dries.
On 2/14/2020 6:09 AM, Alan Perry via cctalk wrote:
The SCSI spec and cabling have a specific way that the conductors
have to be rolled to make a round cable.? Each cable type has a
recommended way that signal and grounds should be paired and in what
proximity in the cable.
For SMD I never saw a formal spec with as much detail as the SCSI
spec, and I don't know if they standardized the cabling. Mainly to
speculate about whether you can use a generic 25-25 or 37-37 straight
thru.
I opened up the drive pedestal chassis. At the panel, a 60-pin ribbon
cable is split between the two D-sub connectors, 36 (with the #1 pin)
on the 37-pin D-sub and 24 on the 25-pin D-sub. The ribbon cable
disappears into the chassis, but there are two 60-pin ribbon cables
come out, one connected to each drive.
As far as the data connectors, I can only access the connector on one
drive. On the drive is a 26-pin IDC connector. The ribbon cable
attached to the connector is 25-pin and each drive has it own 25-pin
D-sub on the back panel.
On Feb 14, 2020, at 04:15, Liam Proven via cctalk
<cctalk at classiccmp.org> wrote:
?On Thu, 13 Feb 2020 at 19:06, Alan Perry via cctalk
<cctalk at classiccmp.org> wrote:
> I supplied part numbers. How can I be more specific?
Oddly, some of us do not have a mental look-up table of Sun part
numbers. In fact I think I can safely say that I could not identify a
single cable of any form for any machine ever made by its part number.
If you can, good for you.
I read the label attached to the cable.
I could tell you what connectors are at each end of the cable, but I
couldn?t tell you how they are wired together and, having no docs on
the cable or an example to check, am dependent on the part number to
tell me that.
alan
I suspect the 25-25 would be sensitive to the type of conductor
pairing and fabrication would work.? The 37-37 bus connector probably
would work with looser electrical specs to substitute in different
cabling.
Also just to make things more entertaining on the Oracle site for sun
hardware they are using the term "Storage Module Drive" to refer to
6g/s SAS drives installed in individual blades for a blade server
system. So the term appears frequently in their online docs, and
including old documents and current documents.
When I was searching the Interwebs by part number, I found something
that categorized the cables as SAS cables, even though the official
name associated with the part number says SMD.
Here's one
example of that term on a page
https://docs.oracle.com/cd/E19452-01/html/821-0911/gkfcf.html
If I'm not far off base, I ran across two vendors who may have made
the controller if they aren't sun, Interphase, and Xylogics.? Also an
article referred to the Sun boards as Eurocard from Xylogics.
Xylogics 753.
The SMD controller is a Xylogics 451. It is a Multibus card, so there
is a Multibus-VME on the VME board between it and the backplane. The
control connector is a 60-pin IDC to ribbon cable split between two
D-sub connectors as above. The data connectors is as above, 26-pin
IDCs to 25-pin ribbon to 25-pin D-sub.
For grins, I tried powering up the drives. They came
up and didn't
make horrible noises.
alan
Thanks
Jim
But if
someone, say, told me "I need some SCSI cables: a MD50 to MD68
cable, 2 ? MD68 to MD68, an MD50 terminator and ideally a DB25 to
MD50," then I would be able to say "yes, I have some of those".
However, since Jim has been a bit more forthcoming, it sounds like I
can't help you.
--
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