DSSI: What was it like?

From: Mzthompson_at_aol.com <(Mzthompson_at_aol.com)>
Date: Sun Oct 15 00:26:04 2000

Bruce Lane <kyrrin_at_bluefeathertech.com> wrote:

> For that matter, what the heck did DSSI abbreviate? My guess:
> Distributed Storage Subsystem Interface.

To which Chuck McManis <cmcmanis_at_mcmanis.com> replied:

> As for the abbreviation DSSI I've heard two different expansions used:
> "Digital Standard Storage Interconnect"
> "Digital Standard System Interconnect"
> I've yet to find something that pins it down definitively.

DEC lists in the manuals for both the DECsystem 5400 and the DECsystem 5500
as:

"Digital Storage System Interconnect"

and states:

The DSSI bus has the following characteristics:

 A 4-Mbytes-per-second bandwidth
 Up to eight nodes
 Eight data lines
 One Parity line
 Eight control lines

And gleened from somewhere a long time ago:

One person wrote:

:DSSI was developed from early SCSI definitions in an attempt to make
:it robust, reliable and versatile (e.g. dual host option was defined
:from the very beginning, while many of today's SCSI controllers still
:can cope with only a single host adapter per bus).

:The additional features made it more expensive then SCSI, and the
:industry decided to go with the cheaper solution.

Another person wrote:

:> Are the two inter-changeable??? (SCSI vs DSSI)

:No. It's interesting, though, that there were vendors whose storage
:controllers had host ports that were software configurable as either
:DSSI or SCSI. I never got close enough to one of these to find out
:if they used the same signal wiring, though [most likely not - it is
:conceivable that logic levels were compatible enough that one could
:use the same line drivers and receivers, but they would still have had
:to have a way to choose connectors that matched the interface type].

FWIW

Mike
Received on Sun Oct 15 2000 - 00:26:04 BST