<s>
The	O
IBM	B-Device
System/36	I-Device
(	O
often	O
abbreviated	O
as	O
S/36	B-Device
)	O
was	O
a	O
midrange	B-Device
computer	I-Device
marketed	O
by	O
IBM	O
from	O
1983	O
to	O
2000	O
-	O
a	O
multi-user	B-Operating_System
,	O
multi-tasking	B-Operating_System
successor	O
to	O
the	O
System/34	B-Device
.	O
</s>
<s>
Like	O
the	O
System/34	B-Device
and	O
the	O
older	O
System/32	B-Device
,	O
the	O
System/36	B-Device
was	O
primarily	O
programmed	O
in	O
the	O
RPG	B-Language
II	I-Language
language	O
.	O
</s>
<s>
One	O
of	O
the	O
machine	O
's	O
optional	O
features	O
was	O
an	O
off-line	O
storage	O
mechanism	O
(	O
on	O
the	O
5360	O
model	O
)	O
that	O
utilized	O
"	O
magazines	O
"	O
–	O
boxes	O
of	O
8-inch	O
floppies	B-Device
that	O
the	O
machine	O
could	O
load	O
and	O
eject	O
in	O
a	O
nonsequential	O
fashion	O
.	O
</s>
<s>
The	O
System/36	B-Device
also	O
had	O
many	O
mainframe	O
features	O
such	O
as	O
programmable	O
job	O
queues	O
and	O
scheduling	O
priority	O
levels	O
.	O
</s>
<s>
While	O
these	O
systems	O
were	O
similar	O
to	O
other	O
manufacturer	O
's	O
minicomputers	B-Architecture
,	O
IBM	O
themselves	O
described	O
the	O
System/32	B-Device
,	O
System/34	B-Device
and	O
System/36	B-Device
as	O
"	O
small	O
systems	O
"	O
and	O
later	O
as	O
midrange	B-Device
computers	I-Device
along	O
with	O
the	O
System/38	B-Device
and	O
succeeding	O
IBM	B-Device
AS/400	I-Device
range	O
.	O
</s>
<s>
The	O
AS/400	B-Device
series	O
and	O
IBM	B-Device
Power	I-Device
Systems	I-Device
running	O
IBM	B-Application
i	I-Application
can	O
run	O
System/36	B-Device
code	O
in	O
the	O
System/36	B-Device
Environment	O
,	O
although	O
the	O
code	O
needs	O
to	O
be	O
recompiled	O
on	O
IBM	B-Application
i	I-Application
first	O
.	O
</s>
<s>
The	O
IBM	B-Device
System/36	I-Device
was	O
a	O
popular	O
small	O
business	O
computer	O
system	O
,	O
first	O
announced	O
on	O
16	O
May	O
1983	O
and	O
shipped	O
later	O
that	O
year	O
.	O
</s>
<s>
The	O
first	O
model	O
of	O
the	O
System/36	B-Device
was	O
the	O
5360	O
.	O
</s>
<s>
At	O
this	O
time	O
,	O
IBM	O
had	O
been	O
about	O
to	O
consolidate	O
its	O
entire	O
line	O
(	O
System/370	B-Device
,	O
4300	B-Device
,	O
System/32	B-Device
,	O
System/34	B-Device
,	O
System/38	B-Device
)	O
into	O
one	O
"	O
family	O
"	O
of	O
computers	O
with	O
the	O
same	O
ISAM	B-Application
database	O
technology	O
,	O
programming	O
languages	O
,	O
and	O
hardware	B-General_Concept
architecture	I-General_Concept
.	O
</s>
<s>
After	O
the	O
lawsuit	O
was	O
filed	O
,	O
IBM	O
decided	O
it	O
would	O
have	O
two	O
families	O
:	O
the	O
System/38	B-Device
line	O
,	O
intended	O
for	O
large	O
companies	O
and	O
representing	O
IBM	O
's	O
future	O
direction	O
,	O
and	O
the	O
System/36	B-Device
line	O
,	O
intended	O
for	O
small	O
companies	O
who	O
had	O
used	O
the	O
company	O
's	O
legacy	O
System/32/34	O
computers	O
.	O
</s>
<s>
In	O
the	O
late	O
1980s	O
the	O
lawsuit	O
was	O
dropped	O
,	O
and	O
IBM	O
decided	O
to	O
recombine	O
the	O
two	O
product	O
lines	O
,	O
creating	O
the	O
AS/400	B-Device
-	O
which	O
replaced	O
both	O
the	O
System/36	B-Device
and	O
System/38	B-Device
.	O
</s>
<s>
The	O
System/36	B-Device
used	O
virtually	O
the	O
same	O
RPG	B-Language
II	I-Language
,	O
Screen	B-Application
Design	I-Application
Aid	I-Application
,	O
OCL	B-Language
,	O
and	O
other	O
technologies	O
that	O
the	O
System/34	B-Device
used	O
,	O
though	O
it	O
was	O
object-code	O
incompatible	O
.	O
</s>
<s>
The	O
S/36	B-Device
was	O
a	O
small	O
business	O
computer	O
;	O
it	O
had	O
an	O
8-inch	O
diskette	B-Device
drive	I-Device
,	O
between	O
one	O
and	O
four	O
hard	B-Device
drives	I-Device
in	O
sizes	O
of	O
30	O
to	O
716	O
MB	O
,	O
and	O
memory	O
from	O
128K	O
up	O
to	O
7MB	O
.	O
</s>
<s>
Tape	O
drives	O
were	O
available	O
as	O
backup	O
devices	O
;	O
the	O
6157	O
QIC	B-Device
(	O
quarter-inch	B-Device
cartridge	I-Device
)	O
and	O
the	O
reel-to-reel	O
8809	O
both	O
had	O
capacities	O
of	O
roughly	O
60MB	O
.	O
</s>
<s>
The	O
Advanced/36	B-Device
9402	O
tape	O
drive	O
had	O
a	O
capacity	O
of	O
2.5GB	O
.	O
</s>
<s>
The	O
IBM	B-Device
5250	I-Device
series	O
of	O
terminals	B-General_Concept
were	O
the	O
primary	O
interface	O
to	O
the	O
System/36	B-Device
.	O
</s>
<s>
S/36s	B-Device
had	O
two	O
sixteen-bit	O
processors	O
,	O
the	O
CSP	O
or	O
Control	O
Storage	O
Processor	O
,	O
and	O
the	O
MSP	O
or	O
Main	O
Storage	O
Processor	O
.	O
</s>
<s>
As	O
with	O
the	O
earlier	O
System/32	B-Device
and	O
System/34	B-Device
hardware	O
,	O
the	O
execution	O
of	O
so-called	O
"	O
scientific	O
instructions	O
"	O
(	O
i.e.	O
</s>
<s>
floating-point	B-Algorithm
operations	I-Algorithm
)	O
was	O
implemented	O
in	O
software	O
on	O
the	O
CSP	O
.	O
</s>
<s>
The	O
first	O
System/36	B-Device
models	O
(	O
the	O
5360-A	O
)	O
had	O
a	O
4MHz	O
CSP	O
and	O
a	O
1MHz	O
MSP	O
.	O
</s>
<s>
If	O
the	O
operator	O
"	O
dialed	O
up	O
"	O
the	O
combination	O
F-F-0-0	O
before	O
performing	O
an	O
Initial	O
Program	O
Load	O
(	O
IPL	O
,	O
or	O
system	B-Operating_System
boot	I-Operating_System
)	O
,	O
many	O
diagnostics	O
were	O
skipped	O
,	O
causing	O
the	O
duration	O
of	O
the	O
IPL	O
to	O
be	O
about	O
a	O
minute	O
instead	O
of	O
about	O
10	O
minutes	O
.	O
</s>
<s>
Of	O
course	O
part	O
of	O
the	O
IPL	O
was	O
typically	O
keysorting	O
the	O
indexed	B-Language
files	I-Language
and	O
if	O
the	O
machine	O
had	O
been	O
shut	O
down	O
without	O
a	O
"	O
keysort	O
"	O
(	O
performed	O
part	O
of	O
the	O
P	O
S	O
(	O
or	O
STOP	O
SYSTEM	O
)	O
then	O
depending	O
on	O
the	O
number	O
of	O
indexed	B-Language
files	I-Language
(	O
and	O
their	O
sizes	O
)	O
it	O
could	O
take	O
upwards	O
of	O
an	O
hour	O
to	O
come	O
back	O
up	O
.	O
</s>
<s>
The	O
smallest	O
S/36	B-Device
had	O
128K	O
of	O
RAM	O
and	O
a	O
30	O
MB	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
The	O
largest	O
configured	O
S/36	B-Device
could	O
support	O
7MB	O
of	O
RAM	O
and	O
1478MB	O
of	O
disk	O
space	O
.	O
</s>
<s>
S/36	B-Device
hard	B-Device
drives	I-Device
contained	O
a	O
feature	O
called	O
"	O
the	O
extra	O
cylinder	O
,	O
"	O
so	O
that	O
bad	O
spots	O
on	O
the	O
drive	O
were	O
detected	O
and	O
dynamically	O
mapped	O
out	O
to	O
good	O
spots	O
on	O
the	O
extra	O
cylinder	O
.	O
</s>
<s>
It	O
is	O
therefore	O
possible	O
for	O
the	O
S/36	B-Device
to	O
use	O
more	O
space	O
than	O
it	O
can	O
technically	O
address	O
.	O
</s>
<s>
Disk	O
address	O
sizes	O
limit	O
the	O
size	O
of	O
the	O
active	O
S/36	B-Device
partition	O
to	O
about	O
2GB	O
;	O
however	O
,	O
the	O
Advanced/36	B-Device
Large	O
Package	O
had	O
a	O
4GB	O
hard	B-Device
drive	I-Device
which	O
could	O
contain	O
up	O
to	O
three	O
(	O
emulated	O
)	O
S/36s	B-Device
,	O
and	O
Advanced/36	B-Device
computers	O
had	O
more	O
memory	O
than	O
SSP	O
could	O
address	O
(	O
32MB	O
to	O
96MB	O
)	O
which	O
was	O
used	O
to	O
increase	O
disk	O
caching	O
.	O
</s>
<s>
Disk	O
space	O
on	O
the	O
System/36	B-Device
was	O
organized	O
by	O
blocks	O
,	O
with	O
one	O
block	O
consisting	O
of	O
2560	O
bytes	O
.	O
</s>
<s>
The	O
System/36	B-Device
supported	O
memory	B-Architecture
paging	I-Architecture
,	O
referring	O
to	O
as	O
"	O
swapping	O
"	O
.	O
</s>
<s>
The	O
System	B-Operating_System
Support	I-Operating_System
Program	I-Operating_System
(	O
SSP	O
)	O
was	O
the	O
only	O
operating	B-General_Concept
system	I-General_Concept
of	O
the	O
S/36	B-Device
.	O
</s>
<s>
It	O
contained	O
support	O
for	O
multiprogramming	O
,	O
multiple	O
processors	O
,	O
80	O
devices	O
,	O
job	O
queues	O
,	O
printer	O
queues	O
,	O
security	O
,	O
indexed	B-Language
file	I-Language
support	O
,	O
and	O
fully	O
installed	O
,	O
it	O
was	O
about	O
10MB	O
.	O
</s>
<s>
On	O
the	O
Advanced/36	B-Device
,	O
the	O
number	O
of	O
workstations/printers	O
was	O
increased	O
to	O
160	O
.	O
</s>
<s>
In	O
the	O
Guest/36	O
environment	O
of	O
certain	O
OS/400	B-Application
releases	O
,	O
up	O
to	O
216	O
devices	O
were	O
supported	O
.	O
</s>
<s>
The	O
S/36	B-Device
could	O
compile	O
and	O
run	O
programs	O
up	O
to	O
64	O
kB	O
in	O
size	O
,	O
although	O
most	O
were	O
not	O
this	O
large	O
.	O
</s>
<s>
With	O
the	O
Advanced/36	B-Device
,	O
there	O
were	O
features	O
added	O
to	O
the	O
SSP	O
operating	B-General_Concept
system	I-General_Concept
including	O
the	O
ability	O
to	O
call	O
other	O
programs	O
from	O
within	O
.	O
</s>
<s>
This	O
call/parm	O
had	O
been	O
available	O
with	O
third-party	O
packages	O
on	O
the	O
System/36	B-Device
but	O
not	O
widely	O
used	O
until	O
the	O
feature	O
was	O
put	O
in	O
7.1	O
and	O
7.5	O
of	O
SSP	O
on	O
the	O
Advanced/36	B-Device
.	O
</s>
<s>
The	O
System/36	B-Device
5360	O
was	O
the	O
first	O
model	O
of	O
System/36	B-Device
.	O
</s>
<s>
The	O
five	O
red	O
lights	O
on	O
the	O
System/36	B-Device
were	O
as	O
follows	O
:	O
</s>
<s>
It	O
used	O
14	O
"	O
fixed	B-Device
disks	I-Device
(	O
30	O
or	O
60MB	O
)	O
and	O
could	O
support	O
up	O
to	O
two	O
;	O
main	O
storage	O
ranged	O
from	O
128KB	O
to	O
512	O
KB	O
.	O
</s>
<s>
One	O
8	B-Device
"	I-Device
floppy	B-Device
diskette	I-Device
drive	O
was	O
built	O
in	O
.	O
</s>
<s>
The	O
model	O
5364	O
was	O
called	O
the	O
"	O
System/36	B-Device
PC	O
"	O
or	O
"	O
Desktop	O
36	O
"	O
(	O
and	O
also	O
,	O
informally	O
,	O
the	O
"	O
Baby/36	O
"	O
by	O
some	O
–	O
but	O
this	O
name	O
was	O
later	O
attached	O
to	O
a	O
software	O
program	O
produced	O
by	O
California	O
Software	O
Products	O
,	O
Inc	O
.	O
)	O
.	O
</s>
<s>
The	O
5364	O
was	O
a	O
June	O
1985	O
attempt	O
by	O
IBM	O
to	O
implement	O
a	O
System/36	B-Device
on	O
PC-sized	O
hardware	O
.	O
</s>
<s>
Inside	O
,	O
there	O
were	O
IBM	O
chips	O
,	O
but	O
the	O
cabinet	O
size	O
was	O
reminiscent	O
of	O
an	O
IBM	B-Operating_System
PC/AT	I-Operating_System
of	O
the	O
period	O
.	O
</s>
<s>
The	O
machine	O
had	O
a	O
1.2	O
MB	O
5.25-inch	O
diskette	B-Device
drive	I-Device
,	O
which	O
was	O
incompatible	O
with	O
PCs	O
and	O
with	O
other	O
S/36s	B-Device
.	O
</s>
<s>
The	O
control	O
panel/system	O
console	O
(	O
connected	O
via	O
an	O
expansion	O
card	O
)	O
was	O
an	O
IBM	B-Device
PC	I-Device
with	O
at	O
least	O
256KB	O
RAM	O
.	O
</s>
<s>
It	O
featured	O
updated	O
hardware	O
using	O
newer	O
,	O
smaller	O
hard	B-Device
drive	I-Device
platters	O
,	O
a	O
5	O
"	O
diskette	B-Device
drive	I-Device
,	O
and	O
a	O
revised	O
distribution	O
of	O
the	O
SSP	O
.	O
</s>
<s>
The	O
System/36	B-Device
Environment	O
of	O
IBM	B-Application
i	I-Application
(	O
previously	O
OS/400	B-Application
)	O
is	O
a	O
feature	O
which	O
provides	O
a	O
number	O
of	O
SSP	O
utilities	O
,	O
as	O
well	O
as	O
RPG	B-Language
II	I-Language
and	O
OCL	B-Language
support	O
.	O
</s>
<s>
It	O
does	O
not	O
implement	O
binary	O
compatibility	O
with	O
the	O
System/36	B-Device
-	O
instead	O
it	O
allows	O
programmers	O
to	O
port	O
System/36	B-Device
applications	O
to	O
IBM	B-Application
i	I-Application
by	O
recompiling	O
the	O
code	O
on	O
top	O
of	O
the	O
System/36	B-Device
Environment	O
,	O
generating	O
programs	O
which	O
use	O
the	O
native	O
IBM	B-Application
i	I-Application
APIs	O
.	O
</s>
<s>
From	O
V3R6	O
to	O
V4R4	O
,	O
OS/400	B-Application
was	O
capable	O
of	O
running	O
up	O
to	O
three	O
instances	O
of	O
SSP	O
inside	O
virtual	B-Architecture
machines	I-Architecture
known	O
as	O
Advanced	O
36	O
Machines	O
.	O
</s>
<s>
This	O
relied	O
on	O
emulation	O
of	O
emulation	O
of	O
the	O
MSP	O
implemented	O
by	O
the	O
OS/400	B-Application
SLIC	O
,	O
and	O
thus	O
provided	O
binary	O
compatibility	O
with	O
SSP	O
programs	O
.	O
</s>
<s>
The	O
AS/Entry	O
was	O
just	O
a	O
stripped-down	O
AS/400	B-Device
,	O
first	O
model	O
was	O
based	O
on	O
a	O
AS/400	B-Device
9401-P03	O
.	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
was	O
SSP	O
Release	O
6	O
.	O
</s>
<s>
This	O
machine	O
was	O
offered	O
c.1991	O
to	O
target	O
customers	O
who	O
had	O
a	O
S/36	B-Device
and	O
wanted	O
to	O
one	O
day	O
migrate	O
to	O
an	O
AS/400	B-Device
,	O
but	O
did	O
not	O
want	O
a	O
large	O
investment	O
in	O
an	O
AS/400	B-Device
.	O
</s>
<s>
The	O
entry	O
line	O
was	O
later	O
upgraded	O
to	O
AS/400	B-Device
9401-150	O
hardware	O
.	O
</s>
<s>
In	O
1994	O
,	O
IBM	O
released	O
the	O
AS/400	B-Device
Advanced/36	B-Device
with	O
two	O
models	O
(	O
9402-236	O
and	O
9402-436	O
)	O
.	O
</s>
<s>
Priced	O
as	O
low	O
as	O
$7995	O
,	O
it	O
was	O
a	O
machine	O
that	O
allowed	O
System/36	B-Device
users	O
to	O
get	O
faster	O
and	O
more	O
modern	O
hardware	O
while	O
"	O
staying	O
36.	O
"	O
</s>
<s>
Based	O
on	O
standard	O
AS/400	B-Device
hardware	O
,	O
the	O
Advanced/36	B-Device
could	O
run	O
SSP	O
,	O
the	O
operating	B-General_Concept
system	I-General_Concept
of	O
the	O
System/36	B-Device
,	O
alone	O
,	O
or	O
within	O
AS/400	B-Device
'	O
s	O
OS/400	B-Application
as	O
a	O
virtual	B-Architecture
machine	I-Architecture
so	O
that	O
it	O
could	O
be	O
upgraded	O
to	O
a	O
full-blown	O
AS/400	B-Device
for	O
just	O
extra	O
licensing	O
costs	O
.	O
</s>
<s>
The	O
Advanced/36	B-Device
bought	O
the	O
world	O
of	O
System/36	B-Device
and	O
SSP	O
about	O
five	O
more	O
years	O
in	O
the	O
marketplace	O
,	O
but	O
by	O
the	O
end	O
of	O
the	O
20th	O
century	O
,	O
the	O
marketplace	O
for	O
the	O
System/36	B-Device
was	O
almost	O
unrecognizable	O
.	O
</s>
<s>
Twinaxial	O
cable	O
had	O
disappeared	O
in	O
favor	O
of	O
cheap	O
adapters	O
and	O
standard	B-Protocol
telephone	I-Protocol
wire	I-Protocol
.	O
</s>
<s>
The	O
System/36	B-Device
was	O
eventually	O
replaced	O
by	O
AS/400s	B-Device
at	O
the	O
high	O
end	O
and	O
PCs	O
at	O
the	O
low	O
end	O
.	O
</s>
<s>
The	O
Advanced	O
line	O
was	O
later	O
upgraded	O
to	O
AS/400	B-Device
9406-170	O
hardware	O
.	O
</s>
<s>
By	O
2000	O
,	O
the	O
Advanced/36	B-Device
was	O
withdrawn	O
from	O
marketing	O
.	O
</s>
