SMD disks

Glen Slick glen.slick at
Fri Aug 30 00:56:49 CDT 2019

On Thu, Aug 29, 2019, 9:27 PM Alan Perry via cctalk <cctalk at>

> On 8/29/19 9:17 PM, Glen Slick via cctalk wrote:
> > On Thu, Aug 29, 2019 at 4:53 PM Alan Perry via cctalk
> > <cctalk at> wrote:
> >>
> >> My Sun 3/260 came with a pair of 8-inch SMD disks in a separate cabinet.
> >>
> >> 1. Anyone have a pointer to docs that describe cabling and configuring
> >> SMD disks? My Google-fu has failed here.
> >>
> >> 2. The system came with no cables (external cables between cabinets).
> >> Are these standard cables or will they be Sun-specific?
> >>
> >> 3. The system "ran when parked" about a dozen years ago, but it was left
> >> in an open barn after that. How likely is it that the disks will work
> >> and be readable? One is a Fujitsu M2333; don't recall what they other
> >> one is.
> >>
> >> alan
> >
> > It has been over 5 years now since I had a Sun 4/280. I gave that away
> > to someone else on the list.
> >
> > That system had an Xylogics 7053 SMD controller with a couple of
> > Hitachi 900MB DK815-10 SMD-E ~8-inch drives. I forget the details now.
> >  From a quick look online the Xylogics 7053 SMD controller has a CMD
> > port, and a DATA 0,1 and a DATA 2,3 port. If I remember right the CMD
> > port was cabled to the CMD in port of the first drive, then the CMD
> > out port of the first drive was cabled to the CMD in port of the
> > second drive, then the CMD out port of the second drive was
> > terminated. The DATA 0,1 port must have had a Y-cable that was split
> > to the DATA ports of each drive.
> On the controller side, there are two command connectors, one wider than
> the other, as well as two data connectors.  On the disk cabinet side,
> there is a connector marked 'data 0', connected to one HDD, another
> marked 'data 1', connected to the other HDD, and two pairs of command
> connectors, one marked 'in' and the other 'out'. I haven't yet followed
> the command cabling to see what the connectors connect to.
> >
> > There were other Xylogics SMD controllers as well. Which controller do
> > you have in your system?
> Xylogics 451.

The diagram on this page it shows that the 60-pin SMD Command connector of
the Xylogics 461 is split into two connectors on the bulkhead panel:

My guess is that it was easier in some way to have two smaller connectors
and cables than a single larger connector and cable. I can't remember now
if the Xylogics 7053 did the same thing with split Command cables.

I assume that in the disk cabinet the two Command In connectors join back
into a standard 60-pin SMD Control connection to the first disk, which is
then chained to the second disk, which is the chained and split again to
the two Command Out connectors.


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