Sun external SMD cables

jim stephens jwsmail at
Sat Feb 15 02:35:35 CST 2020

On 2/14/2020 11:11 PM, Alan Perry via cctech wrote:
> On 2/14/20 1:54 PM, jim stephens via cctech wrote:
>> On 2/14/2020 6:09 AM, Alan Perry via cctalk wrote:
>>>> On Feb 14, 2020, at 04:15, Liam Proven via cctalk 
>>>> <cctalk at> wrote:
>>>> On Thu, 13 Feb 2020 at 19:06, Alan Perry via cctalk
>>>> <cctalk at> 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
>> 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.
>> 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.
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.
>> Here's one example of that term on a page 
>> 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.
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.

> 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.
>>>> -- 
>>>> Liam Proven - Profile:
>>>> Email: lproven at - Google Mail/Hangouts/Plus: 
>>>> lproven at
>>>> Twitter/Facebook/Flickr: lproven - Skype/LinkedIn: liamproven
>>>> UK: +44 7939-087884 - ČR (+ WhatsApp/Telegram/Signal): +420 702 829 
>>>> 053

More information about the cctalk mailing list