<s>
The	O
Digital	B-Architecture
Storage	I-Architecture
Systems	I-Architecture
Interconnect	I-Architecture
(	O
DSSI	O
)	O
is	O
a	O
computer	B-General_Concept
bus	I-General_Concept
developed	O
by	O
Digital	O
Equipment	O
Corporation	O
for	O
connecting	O
storage	O
devices	O
and	O
clustering	O
VAX	B-Device
systems	O
.	O
</s>
<s>
It	O
was	O
designed	O
as	O
a	O
smaller	O
and	O
lower-cost	O
replacement	O
for	O
the	O
earlier	O
DEC	B-Operating_System
Computer	I-Operating_System
Interconnect	I-Operating_System
that	O
would	O
be	O
more	O
suitable	O
for	O
use	O
in	O
office	O
environments	O
.	O
</s>
<s>
DSSI	O
was	O
superseded	O
by	O
Parallel	O
SCSI	B-Architecture
.	O
</s>
<s>
DSSI	O
support	O
was	O
later	O
extended	O
to	O
MIPS-based	O
DECsystems	B-Device
and	O
DEC	O
Alpha-based	O
AlphaServer	B-Device
systems	O
.	O
</s>
<s>
DSSI	O
peripherals	O
could	O
be	O
distinguished	O
from	O
narrow	O
SCSI	B-Architecture
devices	O
by	O
their	O
characteristic	O
five-conductor	O
power	O
connector	O
featuring	O
an	O
extra	O
lead	O
intended	O
for	O
Battery/UPS	O
connection	O
to	O
power	O
critical	O
components	O
in	O
the	O
event	O
of	O
a	O
power	O
failure	O
.	O
</s>
<s>
"	O
The	O
Q-Bus	B-Architecture
5-Enclosure	O
Rule	O
"	O
:	O
For	O
Q-bus	B-Architecture
VMScluster	B-Operating_System
configurations	O
,	O
a	O
maximum	O
of	O
five	O
enclosures	O
,	O
excluding	O
SF200/210s	O
,	O
can	O
be	O
configured	O
on	O
a	O
single	O
DSSI	O
bus	O
.	O
</s>
<s>
"	O
The	O
VAX	B-Device
6000	I-Device
Cabinet	O
Rule	O
"	O
:	O
For	O
a	O
VAX	B-Device
6000	I-Device
DSSI	O
VMScluster	B-Operating_System
system	O
,	O
a	O
maximum	O
of	O
two	O
or	O
three	O
VAX	B-Device
6000	I-Device
systems	O
and	O
one	O
storage	O
cabinet	O
,	O
typically	O
an	O
SF200	O
or	O
SF210	O
,	O
can	O
be	O
configured	O
on	O
a	O
single	O
DSSI	O
bus	O
.	O
</s>
<s>
DSSI	O
SUPPORT	O
IN	O
OpenVMS	B-Operating_System
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.0-2	O
:	O
</s>
<s>
over	O
the	O
Network	O
Interconnect	B-General_Concept
(	O
NI	O
)	O
for	O
MicroVAX	B-Device
3300/3400	O
.	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.1	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.1-1	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.2	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.3	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.3-2	O
:	O
</s>
<s>
o	O
Support	O
for	O
VAX	B-Device
4000	I-Device
.	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.4-2	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.4-3	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
VAX	B-Device
V5.5-2	O
:	O
</s>
<s>
OpenVMS	B-Operating_System
Alpha	B-Device
V1.5	O
,	O
OpenVMS	B-Operating_System
VAX	B-Device
V6.0	O
:	O
</s>
<s>
o	O
Quad-host	O
DSSI	O
configurations	O
with	O
DEC	B-Device
4000	I-Device
AXP	I-Device
systems	O
supported	O
.	O
</s>
<s>
two	O
VAX	B-Device
systems	O
.	O
</s>
<s>
o	O
KFQSA	O
Q-bus	B-Architecture
to	O
DSSI	O
configurations	O
supported	O
.	O
</s>
<s>
same	O
DSSI	O
bus	O
as	O
DEC	B-Device
4000	I-Device
processors	O
.	O
</s>
<s>
CMD	O
manufactured	O
various	O
models	O
of	O
the	O
CDI-4000	O
which	O
would	O
allow	O
SCSI	B-Architecture
peripherals	O
to	O
be	O
used	O
on	O
a	O
DSSI	O
bus	O
.	O
</s>
