<s>
Aleph	O
is	O
a	O
discontinued	O
operating	B-General_Concept
system	I-General_Concept
kernel	O
developed	O
at	O
the	O
University	O
of	O
Rochester	O
as	O
part	O
of	O
their	O
Rochester	O
's	O
Intelligent	O
Gateway	O
(	O
RIG	O
)	O
project	O
in	O
1975	O
.	O
</s>
<s>
Aleph	O
was	O
an	O
early	O
step	O
on	O
the	O
road	O
to	O
the	O
creation	O
of	O
the	O
first	O
practical	O
microkernel	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
,	O
Mach	B-Operating_System
.	O
</s>
<s>
Aleph	O
used	O
inter-process	B-Operating_System
communications	I-Operating_System
to	O
move	O
data	O
between	O
programs	O
and	O
the	O
kernel	O
,	O
so	O
applications	O
could	O
transparently	O
access	O
resources	O
on	O
any	O
machine	O
on	O
the	O
local	O
area	O
network	O
(	O
which	O
at	O
the	O
time	O
was	O
a	O
3-Mbit/s	O
experimental	O
Xerox	O
Ethernet	O
)	O
.	O
</s>
<s>
The	O
project	O
eventually	O
petered	O
out	O
after	O
several	O
years	O
due	O
to	O
rapid	O
changes	O
in	O
the	O
computer	O
hardware	O
market	O
,	O
but	O
the	O
ideas	O
led	O
to	O
the	O
creation	O
of	O
Accent	B-Operating_System
at	O
Carnegie	O
Mellon	O
University	O
,	O
leading	O
in	O
turn	O
to	O
Mach	B-Operating_System
.	O
</s>
<s>
Ports	O
were	O
essentially	O
message	O
queues	O
that	O
were	O
maintained	O
by	O
the	O
Aleph	B-Operating_System
kernel	I-Operating_System
,	O
identified	O
by	O
a	O
machine	O
unique	O
(	O
as	O
opposed	O
to	O
globally	O
unique	O
)	O
ID	O
consisting	O
of	O
a	O
process	O
id	O
,	O
port	O
id	O
pair	O
.	O
</s>
<s>
RIG	O
was	O
implemented	O
on	O
a	O
number	O
of	O
Data	B-Device
General	I-Device
Eclipse	I-Device
minicomputers	B-Architecture
.	O
</s>
