<s>
The	O
IBM	B-Device
System/390	I-Device
is	O
a	O
discontinued	O
mainframe	B-Device
product	O
family	O
implementing	O
the	O
ESA/390	O
,	O
the	O
fifth	O
generation	O
of	O
the	O
System/360	B-Application
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
.	O
</s>
<s>
The	O
first	O
computers	O
to	O
use	O
the	O
ESA/390	O
were	O
the	O
Enterprise	B-Device
System/9000	I-Device
(	O
ES/9000	B-Device
)	O
family	O
,	O
which	O
were	O
introduced	O
in	O
1990	O
.	O
</s>
<s>
These	O
were	O
followed	O
by	O
the	O
9672	O
,	O
Multiprise	B-Device
,	O
and	O
Integrated	O
Server	O
families	O
of	O
System/390	B-Device
in	O
1994	O
–	O
1999	O
,	O
using	O
CMOS	B-Device
microprocessors	O
.	O
</s>
<s>
The	O
ESA/390	O
succeeded	O
the	O
ESA/370	O
used	O
in	O
the	O
Enhanced	O
3090	B-Device
and	O
4381	O
"	O
E	O
"	O
models	O
,	O
and	O
the	O
System/370	B-Device
architecture	O
last	O
used	O
in	O
the	O
IBM	B-Device
9370	I-Device
low-end	O
mainframe	B-Device
.	O
</s>
<s>
The	O
ESA/390	O
was	O
succeeded	O
by	O
the	O
64-bit	B-Device
z/Architecture	B-Device
in	O
2000	O
.	O
</s>
<s>
Enterprise	O
Systems	O
Architecture/370	O
(	O
ESA/370	O
)	O
for	O
3090	B-Device
enhanced	O
(	O
"	O
E	O
"	O
)	O
models	O
and	O
for	O
4381	O
model	O
groups	O
91E	O
and	O
92E	O
.	O
</s>
<s>
In	O
additional	O
to	O
the	O
primary	O
and	O
secondary	O
addressing	O
modes	O
that	O
System/370	B-Device
Extended	O
Architecture	O
(	O
S/370	B-Device
-XA	I-Device
)	O
supports	O
,	O
ESA	O
has	O
an	O
access	B-Application
register	I-Application
mode	O
in	O
which	O
each	O
use	O
of	O
general	O
register	O
1-15	O
as	O
a	O
base	O
register	O
uses	O
an	O
associated	O
access	B-Application
register	I-Application
to	O
select	O
an	O
address	O
space	O
.	O
</s>
<s>
System/390	B-Device
(	O
S/390	B-Device
)	O
,	O
as	O
in	O
360	O
for	O
1960s	O
,	O
370	O
for	O
1970s	O
.	O
</s>
<s>
Enterprise	B-Device
System/9000	I-Device
(	O
ES/9000	B-Device
)	O
,	O
as	O
in	O
360	O
for	O
1960s	O
,	O
370	O
for	O
1970s	O
.	O
</s>
<s>
Enterprise	B-Device
Systems	I-Device
Architecture/390	I-Device
(	O
ESA/390	O
)	O
was	O
IBM	O
's	O
last	O
31-bit-address/32	O
-bit-data	O
mainframe	B-Architecture
computing	I-Architecture
design	O
,	O
copied	O
by	O
Amdahl	O
,	O
Hitachi	O
,	O
and	O
Fujitsu	O
among	O
other	O
competitors	O
.	O
</s>
<s>
It	O
was	O
the	O
successor	O
of	O
ESA/370	O
and	O
,	O
in	O
turn	O
,	O
was	O
succeeded	O
by	O
the	O
64-bit	B-Device
z/Architecture	B-Device
in	O
2000	O
.	O
</s>
<s>
Among	O
other	O
things	O
,	O
ESA/390	O
added	O
fiber	O
optics	O
channels	B-Device
,	O
known	O
as	O
Enterprise	B-Device
Systems	I-Device
Connection	I-Device
(	O
ESCON	B-Device
)	O
channels	B-Device
,	O
to	O
the	O
parallel	O
(	O
Bus	B-Device
and	I-Device
Tag	I-Device
)	O
channels	B-Device
of	O
ESA/370	O
.	O
</s>
<s>
Despite	O
the	O
fact	O
that	O
IBM	O
mentioned	O
the	O
9000	O
family	O
first	O
in	O
some	O
of	O
the	O
day	O
's	O
announcements	O
,	O
it	O
was	O
clear	O
"	O
by	O
the	O
end	O
of	O
the	O
day	O
"	O
that	O
it	O
was	O
"	O
for	O
System/390	B-Device
,	O
"	O
although	O
it	O
was	O
a	O
shortened	O
name	O
,	O
S/390	B-Device
,	O
that	O
was	O
placed	O
on	O
some	O
of	O
the	O
actual	O
"	O
boxes	O
"	O
later	O
shipped	O
.	O
</s>
<s>
The	O
ES/9000	B-Device
include	O
rack-mounted	O
models	O
,	O
free	O
standing	O
air	O
cooled	O
models	O
and	O
water	O
cooled	O
models	O
.	O
</s>
<s>
The	O
low	O
end	O
models	O
were	O
substantially	O
less	O
expensive	O
than	O
the	O
3090	B-Device
or	O
4381	O
previously	O
needed	O
to	O
run	O
MVS/ESA	O
,	O
and	O
could	O
also	O
run	O
VM/ESA	B-Application
and	O
VSE/ESA	O
,	O
which	O
IBM	O
announced	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Machines	O
supporting	O
the	O
architecture	O
were	O
sold	O
under	O
the	O
brand	O
System/390	B-Device
(	O
S/390	B-Device
)	O
from	O
September	O
1990	O
.	O
</s>
<s>
The	O
9672	O
implementations	O
of	O
System/390	B-Device
were	O
the	O
first	O
high-end	O
IBM	B-Device
mainframe	I-Device
architecture	O
implemented	O
first	O
with	O
CMOS	B-Device
CPU	O
electronics	O
rather	O
than	O
the	O
traditional	O
bipolar	O
logic	O
.	O
</s>
<s>
The	O
IBM	O
z13	O
was	O
the	O
last	O
z	B-Device
Systems	I-Device
server	O
to	O
support	O
running	O
an	O
operating	O
system	O
in	O
ESA/390	O
architecture	O
mode	O
.	O
</s>
<s>
The	O
architecture	O
(	O
the	O
Linux	O
kernel	O
architecture	O
designation	O
is	O
"	O
s390	B-Device
"	O
;	O
"	O
s390x	O
"	O
designates	O
the	O
64-bit	B-Device
z/Architecture	B-Device
)	O
employs	O
a	O
channel	B-Device
I/O	I-Device
subsystem	O
in	O
the	O
System/370	B-Device
Extended	O
Architecture	O
(	O
S/370	B-Device
-XA	I-Device
)	O
tradition	O
,	O
offloading	O
almost	O
all	O
I/O	O
activity	O
to	O
specialized	O
hardware	O
more	O
sophisticated	O
than	O
the	O
S/360	B-Application
and	O
S/370	B-Device
I/O	B-Device
channels	I-Device
.	O
</s>
<s>
The	O
architecture	O
maintains	O
problem	O
state	O
backward	B-General_Concept
compatibility	I-General_Concept
back	O
to	O
1964	O
with	O
the	O
24-bit-address/32	O
-bit-data	O
(	O
System/360	B-Application
and	O
System/370	B-Device
)	O
and	O
subsequent	O
24/31-bit-address/32	O
-bit-data	O
architectures	O
(	O
System/370	B-Device
-XA	I-Device
and	O
ESA/370	O
)	O
.	O
</s>
<s>
However	O
,	O
the	O
I/O	O
subsystem	O
is	O
based	O
on	O
System/370	B-Device
Extended	O
Architecture	O
(	O
S/370	B-Device
-XA	I-Device
)	O
,	O
not	O
on	O
the	O
original	O
S/370	B-Device
I/O	O
instructions	O
.	O
</s>
<s>
ESA/390	O
is	O
essentially	O
a	O
32-bit	O
architecture	O
;	O
as	O
with	O
System/360	B-Application
,	O
System/370	B-Device
,	O
370-XA	O
,	O
and	O
ESA/370	O
,	O
the	O
general-purpose	O
registers	O
are	O
32	O
bits	O
long	O
,	O
and	O
the	O
arithmetic	O
instructions	O
support	O
32-bit	O
arithmetic	O
.	O
</s>
<s>
In	O
the	O
ES/9000	B-Device
the	O
Central	O
Storage	O
is	O
limited	O
to	O
2GB	O
,	O
but	O
additional	O
memory	O
can	O
be	O
configured	O
as	O
expanded	O
storage	O
.	O
</s>
<s>
Expanded	O
Storage	O
can	O
be	O
used	O
for	O
ultra-fast	O
paging	B-Architecture
,	O
for	O
disk	O
caching	O
,	O
and	O
for	O
virtual	O
disks	O
within	O
the	O
VM/CMS	B-Application
operating	O
system	O
.	O
</s>
<s>
Under	O
Linux/390	B-Application
this	O
memory	O
cannot	O
be	O
used	O
for	O
disk	O
caching	O
;	O
instead	O
,	O
it	O
is	O
supported	O
by	O
a	O
block	O
device	O
driver	O
,	O
allowing	O
to	O
use	O
it	O
as	O
ultra-fast	O
swap	O
space	O
and	O
for	O
RAM	B-Application
drives	I-Application
.	O
</s>
<s>
In	O
addition	O
,	O
a	O
machine	O
may	O
be	O
divided	O
into	O
Logical	B-Device
Partitions	I-Device
(	O
LPARs	B-Device
)	O
,	O
each	O
with	O
its	O
own	O
virtual	O
system	O
memory	O
so	O
that	O
multiple	O
operating	O
systems	O
may	O
run	O
concurrently	O
on	O
one	O
machine	O
.	O
</s>
<s>
An	O
important	O
capability	O
to	O
form	O
a	O
Parallel	B-Operating_System
Sysplex	I-Operating_System
was	O
added	O
to	O
the	O
architecture	O
in	O
1994	O
.	O
</s>
<s>
Some	O
PC-based	B-Operating_System
IBM-compatible	I-Operating_System
mainframes	I-Operating_System
which	O
provide	O
ESA/390	O
processors	O
in	O
smaller	O
machines	O
have	O
been	O
released	O
over	O
time	O
,	O
but	O
are	O
only	O
intended	O
for	O
software	O
development	O
.	O
</s>
<s>
The	O
Hercules	B-Application
emulator	I-Application
is	O
a	O
portable	O
ESA/390	O
and	O
z/Architecture	B-Device
machine	O
emulator	O
which	O
supports	O
enough	O
devices	O
to	O
boot	O
many	O
ESA/390	O
operating	O
systems	O
.	O
</s>
<s>
Since	O
it	O
is	O
written	O
in	O
pure	O
C	O
,	O
it	O
has	O
been	O
ported	O
to	O
many	O
platforms	O
,	O
including	O
S/390	B-Device
itself	O
.	O
</s>
<s>
A	O
commercial	O
emulation	O
product	O
for	O
IBM	B-Operating_System
xSeries	I-Operating_System
with	O
higher	O
execution	O
speed	O
is	O
also	O
available	O
.	O
</s>
<s>
Specific	O
I/O	O
-Device	O
Commands	O
in	O
Enterprise	B-Device
Systems	I-Device
Architecture/390	I-Device
Common	O
I/O	O
-Device	O
Commands	O
shows	O
the	O
following	O
commands	O
.	O
</s>
<s>
Eighteen	O
models	O
were	O
announced	O
September	O
5	O
,	O
1990	O
for	O
the	O
ES/9000	B-Device
in	O
three	O
form	O
factors	O
;	O
the	O
water-cooled	O
9021	O
to	O
succeed	O
the	O
IBM	B-Device
3090	I-Device
,	O
and	O
the	O
air-cooled	O
standalone	O
9121	O
and	O
rack-mounted	O
9221	O
to	O
succeed	O
the	O
IBM	O
4381	O
and	O
9370	B-Device
respectively	O
.	O
</s>
<s>
The	O
9221	O
models	O
120	O
,	O
130	O
and	O
150	O
were	O
initially	O
available	O
only	O
with	O
the	O
"	O
System/370	B-Device
Base	O
Option	O
"	O
;	O
the	O
"	O
ESA	O
Option	O
"	O
shipped	O
in	O
July	O
1991	O
.	O
</s>
<s>
The	O
9221	O
processors	O
were	O
made	O
of	O
VLSI	O
CMOS	B-Device
chips	O
designed	O
in	O
Böblingen	O
,	O
Germany	O
,	O
whence	O
the	O
9672	O
line	O
later	O
originated	O
.	O
</s>
<s>
The	O
lower	O
6	O
of	O
the	O
8	O
water-cooled	O
models	O
(	O
codenamed	O
H0	O
)	O
were	O
immediately	O
available	O
,	O
but	O
used	O
the	O
same	O
processor	O
as	O
the	O
3090-J	O
,	O
still	O
at	O
the	O
69MHz	O
(	O
14.5ns	O
)	O
maximum	O
frequency	O
and	O
thus	O
with	O
unchanged	O
performance	O
.	O
</s>
<s>
Those	O
models	O
 '	O
main	O
difference	O
from	O
the	O
3090-J	O
was	O
the	O
optional	O
addition	O
of	O
ESCON	B-Device
,	O
Sysplex	O
and	O
Integrated	O
Cryptographic	O
Feature	O
.	O
</s>
<s>
Only	O
the	O
models	O
900	O
and	O
820	O
had	O
an	O
all-new	O
design	O
(	O
codenamed	O
H2	O
)	O
,	O
featuring	O
private	O
split	O
I+D	O
128+128	O
KB	O
L1	O
caches	O
and	O
a	O
shared	O
4MB	O
L2	O
cache	O
(	O
2MB	O
per	O
side	O
)	O
with	O
11-cycle	O
latency	O
,	O
more	O
direct	O
interconnects	O
between	O
the	O
processors	O
,	O
multi-level	O
TLBs	B-Architecture
,	O
branch	B-General_Concept
target	I-General_Concept
buffer	I-General_Concept
and	O
111MHz	O
(	O
9ns	O
)	O
clock	O
frequency	O
.	O
</s>
<s>
These	O
were	O
the	O
first	O
models	O
with	O
out-of-order	B-General_Concept
execution	I-General_Concept
since	O
the	O
System/370	B-Device
-195	O
of	O
1973	O
.	O
</s>
<s>
However	O
unlike	O
the	O
old	O
S/360	O
-91-derived	O
systems	O
,	O
the	O
models	O
900	O
and	O
820	O
had	O
full	O
out-of-order	B-General_Concept
execution	I-General_Concept
for	O
both	O
integer	O
and	O
floating-point	O
units	O
,	O
with	O
precise	O
exception	O
handling	O
,	O
and	O
a	O
fully	O
superscalar	B-General_Concept
pipeline	O
.	O
</s>
<s>
These	O
models	O
,	O
codenamed	O
H5	O
,	O
had	O
double	O
the	O
L2	O
cache	O
and	O
30%	O
higher	O
per-processor	O
performance	O
than	O
the	O
H2	O
line	O
,	O
and	O
added	O
a	O
hardware	O
data	B-Algorithm
compression	I-Algorithm
.	O
</s>
<s>
In	O
April	O
1994	O
,	O
alongside	O
the	O
CMOS-based	O
new	O
9672	O
series	O
and	O
improved	O
9221	O
models	O
,	O
IBM	O
announced	O
also	O
their	O
ultimate	O
bipolar	O
model	O
,	O
the	O
10-processor	O
model	O
9X2	O
rated	O
at	O
468	O
MIPS	O
,	O
to	O
become	O
available	O
in	O
October	O
.	O
</s>
<s>
+	O
ES/9000	B-Device
air-cooled	O
standalone	O
models	O
(	O
9121-	O
###	O
)	O
Model	O
CPUs	O
Sides	O
Max	O
storage( main	O
+	O
expanded	O
)	O
Max	O
channels(Max ESCON )	O
Shipping	O
from	O
320-based	O
models	O
Note	O
that	O
the	O
"	O
Mb	O
"	O
here	O
means	O
megabyte	O
,	O
not	O
megabit	O
.	O
</s>
<s>
Vector	B-Operating_System
Facility	I-Operating_System
:	O
up	O
to	O
one	O
vector	B-Operating_System
processor	I-Operating_System
per	O
Central	O
Processor	O
available	O
on	O
the	O
9021	O
and	O
9121	O
.	O
</s>
<s>
First	O
used	O
on	O
the	O
3090	B-Device
to	O
replace	O
the	O
IBM	O
3838	O
array	B-Operating_System
processor	I-Operating_System
announced	O
in	O
1976	O
for	O
System/370	B-Device
.	O
</s>
<s>
(	O
Each	O
Central	O
Processor	O
accommodates	O
one	O
coprocessor	B-General_Concept
at	O
a	O
time	O
;	O
the	O
combined	O
number	O
of	O
installed	O
Vector	B-Operating_System
Facilities	I-Operating_System
and	O
ICRFs	O
cannot	O
exceed	O
the	O
number	O
of	O
Central	O
Processors	O
.	O
)	O
</s>
<s>
The	O
new	O
models	O
of	O
the	O
9021	O
and	O
9121	O
from	O
1993	O
feature	O
data	B-Algorithm
compression	I-Algorithm
hardware	O
.	O
</s>
<s>
Previously	O
available	O
only	O
on	O
IBM	B-Device
3090	I-Device
,	O
Logical	B-Device
Partitions	I-Device
(	O
LPARs	B-Device
)	O
are	O
a	O
standard	O
feature	O
of	O
the	O
ES/9000	B-Device
processors	O
whereby	O
IBM	O
's	O
Processor	B-Device
Resource/Systems	I-Device
Manager	I-Device
(	O
PR/SM	B-Device
)	O
hypervisor	B-Operating_System
allows	O
different	O
operating	O
systems	O
to	O
run	O
concurrently	O
in	O
separate	O
logical	B-Device
partitions	I-Device
(	O
LPARs	B-Device
)	O
,	O
with	O
a	O
high	O
degree	O
of	O
isolation	O
.	O
</s>
<s>
Initially	O
7	O
partitions	B-Device
per	O
a	O
disconnected	O
side	O
were	O
supported	O
.	O
</s>
<s>
In	O
December	O
1992	O
the	O
LPAR	B-Device
capacity	O
of	O
the	O
H2	O
(	O
520-based	O
)	O
models	O
was	O
increased	O
to	O
10	O
per	O
a	O
disconnected	O
side	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
two-processor	O
model	O
660	O
could	O
now	O
support	O
up	O
to	O
20	O
partitions	B-Device
instead	O
of	O
14	O
,	O
if	O
the	O
two	O
sides	O
(	O
each	O
with	O
one	O
processor	O
)	O
are	O
electrically	O
isolated	O
.	O
</s>
<s>
Launched	O
in	O
1994	O
first	O
as	O
the	O
"	O
Parallel	O
Transaction	O
Server	O
"	O
(	O
alongside	O
the	O
9673	O
"	O
Parallel	O
Query	O
Server	O
"	O
)	O
,	O
subsumed	O
by	O
the	O
"	O
Parallel	O
Enterprise	O
Server	O
"	O
launched	O
later	O
in	O
the	O
year	O
,	O
the	O
six	O
generations	O
of	O
the	O
IBM	O
9672	O
machines	O
transitioned	O
IBM	O
's	O
mainframes	B-Architecture
fully	O
to	O
CMOS	B-Device
microprocessors	O
,	O
as	O
by	O
a	O
strategic	O
decision	O
no	O
more	O
ES/9000	B-Device
(	O
bipolar-based	O
except	O
the	O
9221	O
)	O
models	O
would	O
be	O
released	O
after	O
1994	O
.	O
</s>
<s>
The	O
initial	O
generations	O
of	O
9672	O
were	O
slower	O
than	O
the	O
largest	O
ES/9000	B-Device
sold	O
in	O
parallel	O
,	O
but	O
the	O
fifth	O
and	O
sixth	O
generations	O
were	O
the	O
most	O
powerful	O
and	O
capable	O
ESA/390	O
machines	O
built	O
by	O
IBM	O
.	O
</s>
<s>
At	O
370	O
MHz	O
it	O
was	O
the	O
second-highest	O
clocked	O
microprocessor	O
at	O
the	O
time	O
,	O
after	O
the	O
Alpha	B-General_Concept
21164	I-General_Concept
of	O
DEC	O
.	O
</s>
<s>
Arriving	O
in	O
late	O
September	O
1998	O
,	O
the	O
G5	O
more	O
than	O
doubled	O
the	O
performance	O
over	O
any	O
previous	O
IBM	B-Device
mainframe	I-Device
,	O
and	O
restored	O
IBM	O
's	O
performance	O
lead	O
that	O
had	O
been	O
lost	O
to	O
Hitachi	O
's	O
Skyline	O
mainframes	B-Architecture
in	O
1995	O
.	O
</s>
<s>
The	O
thousandth	O
G5	O
system	O
shipped	O
less	O
than	O
100	O
days	O
after	O
the	O
manufacturing	O
began	O
;	O
the	O
greatest	O
ramping	O
of	O
production	O
in	O
S/390	B-Device
'	O
s	O
history	O
.	O
</s>
<s>
In	O
September	O
1996	O
IBM	O
launched	O
the	O
S/390	B-Device
Multiprise	B-Device
2000	I-Device
,	O
positioned	O
below	O
the	O
9672	O
.	O
</s>
<s>
The	O
9672	O
G3	O
and	O
the	O
Multiprise	B-Device
2000	I-Device
were	O
the	O
last	O
versions	O
to	O
support	O
pre-XA	O
System/370	B-Device
mode	O
.	O
</s>
<s>
In	O
October	O
1997	O
models	O
of	O
Multiprise	B-Device
2000	I-Device
with	O
an	O
11%	O
higher	O
performance	O
were	O
launched	O
.	O
</s>
<s>
The	O
Multiprise	B-Device
3000	I-Device
,	O
based	O
on	O
the	O
9672	O
G5	O
,	O
became	O
available	O
in	O
September	O
1999	O
,	O
featuring	O
PCI	B-Protocol
buses	O
.	O
</s>
<s>
The	O
S/390	B-Operating_System
Integrated	I-Operating_System
Server	I-Operating_System
,	O
an	O
even	O
lower-end	O
S/390	B-Device
system	O
than	O
Multiprise	B-Device
,	O
shipped	O
by	O
the	O
end	O
of	O
1998	O
.	O
</s>
<s>
It	O
emerged	O
from	O
a	O
line	O
of	O
S/390-compatibility/coprocessor	O
cards	O
for	O
PCs	O
,	O
but	O
is	O
a	O
true	O
S/390	B-Device
system	O
capable	O
of	O
server	O
duties	O
,	O
having	O
relegated	O
the	O
Pentium	O
II	O
to	O
the	O
role	O
of	O
an	O
I/O	O
coprocessor	B-General_Concept
.	O
</s>
<s>
It	O
was	O
the	O
first	O
S/390	B-Device
server	O
to	O
support	O
PCI	B-Protocol
.	O
</s>
<s>
From	O
1997	O
IBM	O
also	O
offered	O
a	O
"	O
S/390	B-Device
Application	O
StarterPak	O
"	O
,	O
intended	O
as	O
a	O
devkit	B-Application
for	O
developing	O
and	O
testing	O
mainframe	B-Device
software	O
.	O
</s>
