Sun external SMD cables

Alan Perry aperry at
Sat Feb 15 01:11:37 CST 2020

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.

> 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.

For grins, I tried powering up the drives. They came up and didn't make 
horrible noises.


> 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

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