<s>
Midrange	B-Device
computers	I-Device
,	O
or	O
midrange	B-Device
systems	I-Device
,	O
were	O
a	O
class	O
of	O
computer	O
systems	O
that	O
fell	O
in	O
between	O
mainframe	B-Architecture
computers	I-Architecture
and	O
microcomputers	B-Architecture
.	O
</s>
<s>
This	O
class	O
of	O
machine	O
emerged	O
in	O
the	O
1960s	O
,	O
with	O
models	O
from	O
Digital	O
Equipment	O
Corporation	O
(	O
PDP	B-Device
line	O
)	O
,	O
Data	O
General	O
(	O
NOVA	O
)	O
,	O
Hewlett-Packard	O
(	O
HP3000	B-Device
)	O
widely	O
used	O
in	O
science	O
and	O
research	O
as	O
well	O
as	O
for	O
business	O
-	O
and	O
referred	O
to	O
as	O
minicomputers	B-Architecture
.	O
</s>
<s>
IBM	O
favored	O
the	O
term	O
"	O
midrange	B-Device
computer	I-Device
"	O
for	O
their	O
comparable	O
,	O
but	O
more	O
business-oriented	O
systems	O
.	O
</s>
<s>
System/32	B-Device
(	O
introduced	O
in	O
1975	O
)	O
was	O
a	O
16-bit	O
single-user	O
system	O
also	O
known	O
as	O
the	O
IBM	B-Device
5320	I-Device
.	O
</s>
<s>
System/34	B-Device
(	O
1977	O
)	O
was	O
intended	O
to	O
be	O
a	O
successor	O
to	O
both	O
the	O
3	O
and	O
the	O
32	O
.	O
</s>
<s>
System/38	B-Device
(	O
1979	O
)	O
was	O
the	O
first	O
midrange	B-Device
system	I-Device
to	O
have	O
an	O
integrated	O
relational	B-Application
database	I-Application
management	I-Application
system	I-Application
(	O
DBMS	O
)	O
.	O
</s>
<s>
The	O
S/38	B-Device
had	O
48-bit	O
addressing	O
,	O
and	O
ran	O
the	O
CPF	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
System/36	B-Device
(	O
1983	O
)	O
had	O
two	O
16-bit	O
processors	O
with	O
an	O
operating	B-General_Concept
system	I-General_Concept
that	O
supported	O
multiprogramming	O
.	O
</s>
<s>
AS/400	B-Device
was	O
introduced	O
under	O
that	O
name	O
in	O
1988	O
,	O
renamed	O
eServer	B-Device
iSeries	I-Device
in	O
2000	O
,	O
and	O
subsequently	O
became	O
the	O
IBM	B-Device
System	I-Device
i	I-Device
in	O
2006	O
.	O
</s>
<s>
It	O
runs	O
the	O
OS/400	B-Application
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
IBM	B-Device
Power	I-Device
Systems	I-Device
were	O
introduced	O
in	O
April	O
2008	O
,	O
a	O
convergence	O
of	O
IBM	B-Device
System	I-Device
i	I-Device
and	O
IBM	B-Device
System	I-Device
p	I-Device
.	O
</s>
<s>
The	O
main	O
similarity	O
of	O
midrange	B-Device
computers	I-Device
and	O
mainframes	B-Architecture
-	O
they	O
are	O
both	O
oriented	O
for	O
decimal-precision	O
computing	O
and	O
high	O
volume	O
input	O
and	O
output	O
(	O
I/O	O
)	O
,	O
but	O
most	O
midrange	B-Device
computers	I-Device
have	O
an	O
(	O
reduced	O
and	O
specially	O
designed	O
)	O
internal	O
architecture	O
with	O
limited	O
compatibility	O
to	O
mainframes	B-Architecture
.	O
</s>
<s>
The	O
low-end	O
mainframe	B-Architecture
can	O
be	O
more	O
affordable	O
and	O
less	O
powerful	O
that	O
a	O
hi-end	O
midrange	B-Device
system	I-Device
,	O
but	O
midrange	B-Device
system	I-Device
still	O
was	O
a	O
"	O
replacement	O
solution	O
"	O
with	O
another	O
service	O
process	O
,	O
different	O
OS	O
and	O
internal	O
architecture	O
.	O
</s>
<s>
The	O
difference	O
between	O
similar-size	O
Midrange	O
and	O
Supermini/Minicomputer	O
-	O
is	O
a	O
computing	O
purposes	O
:	O
Super/mini	O
oriented	O
for	O
float-point	O
scientific	O
computing	O
,	O
midrange	O
-	O
for	O
decimal	O
business-oriented	O
computing	O
,	O
but	O
without	O
clear	O
distinction	O
border	O
between	O
classes	O
.	O
</s>
<s>
Earliest	O
midrange	B-Device
computers	I-Device
was	O
a	O
single-user	O
business	O
calculation	O
machines	O
;	O
the	O
virtualization	O
,	O
typical	O
feature	O
of	O
mainframes	B-Architecture
since	O
1972	O
(	O
partially	O
from	O
1965	O
)	O
,	O
was	O
ported	O
to	O
midrange	B-Device
systems	I-Device
only	O
in	O
1977	O
;	O
the	O
multi-user	O
support	O
was	O
added	O
to	O
midranges	O
in	O
1976	O
instead	O
of	O
1972	O
for	O
mainframes	B-Architecture
(	O
but	O
that	O
's	O
still	O
a	O
significantly	O
earlier	O
that	O
a	O
limited	O
release	O
of	O
x86	O
virtualization	O
(	O
1985/87	O
)	O
or	O
multi-user	O
support	O
(	O
1983	O
)	O
)	O
.	O
</s>
<s>
Latest	O
midrange	B-Device
systems	I-Device
are	O
primarily	O
mid-class	O
multi-user	O
local	O
network	O
servers	O
that	O
can	O
handle	O
the	O
large-scale	O
processing	O
of	O
many	O
business	B-Application
applications	I-Application
.	O
</s>
<s>
Although	O
not	O
as	O
powerful	O
and	O
reliably	O
as	O
full-size	O
mainframe	B-Architecture
computers	I-Architecture
,	O
they	O
are	O
less	O
costly	O
to	O
buy	O
,	O
operate	O
,	O
and	O
maintain	O
than	O
mainframe	B-Architecture
systems	O
and	O
thus	O
meet	O
the	O
computing	O
needs	O
of	O
many	O
organizations	O
.	O
</s>
<s>
Midrange	B-Device
systems	I-Device
was	O
relatively	O
popular	O
as	O
powerful	O
network	O
servers	O
to	O
help	O
manage	O
large	O
Internet	O
Web	O
sites	O
,	O
but	O
more	O
oriented	O
for	O
corporate	O
intranets	O
and	O
extranets	O
,	O
and	O
other	O
networks	O
.	O
</s>
<s>
Today	O
,	O
midrange	B-Device
systems	I-Device
include	O
servers	O
used	O
in	O
industrial	O
process-control	O
and	O
manufacturing	O
plants	O
and	O
play	O
major	O
roles	O
in	O
computer-aided	O
manufacturing	O
(	O
CAM	O
)	O
.	O
</s>
<s>
Midrange	B-Device
system	I-Device
are	O
also	O
used	O
as	O
front-end	O
servers	O
to	O
assist	O
mainframe	B-Architecture
computers	I-Architecture
in	O
telecommunications	O
processing	O
and	O
network	O
management	O
.	O
</s>
<s>
Since	O
the	O
end	O
of	O
1980s	O
,	O
when	O
the	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
model	I-Operating_System
of	O
computing	O
became	O
predominant	O
,	O
computers	O
of	O
the	O
comparable	O
class	O
are	O
instead	O
usually	O
known	O
as	O
workgroup	O
servers	O
and	O
online	B-General_Concept
transaction	I-General_Concept
processing	I-General_Concept
servers	O
to	O
recognize	O
that	O
they	O
usually	O
"	O
serve	O
"	O
end	O
users	O
at	O
their	O
"	O
client	O
"	O
computers	O
.	O
</s>
<s>
For	O
the	O
1990-2000	O
'	O
s	O
,	O
in	O
some	O
non-critical	O
cases	O
both	O
lines	O
were	O
replaced	O
by	O
web	B-Application
servers	I-Application
,	O
oriented	O
for	O
working	O
with	O
global	O
network	O
,	O
but	O
with	O
less	O
security	O
background	O
,	O
and	O
mainly	O
based	O
using	O
General	O
purpose	O
architecture	O
(	O
currently	O
x86	O
or	O
ARM	O
)	O
.	O
</s>
