<s>
PL360	B-Language
(	O
or	O
PL/360	B-Language
)	O
is	O
a	O
system	B-Language
programming	I-Language
language	I-Language
designed	O
by	O
Niklaus	O
Wirth	O
and	O
written	O
by	O
Wirth	O
,	O
Joseph	O
W	O
.	O
Wells	O
Jr.	O
,	O
and	O
Edwin	O
Satterthwaite	O
Jr.	O
for	O
the	O
IBM	B-Application
System/360	I-Application
computer	O
at	O
Stanford	O
University	O
.	O
</s>
<s>
A	O
description	O
of	O
PL360	B-Language
was	O
published	O
in	O
early	O
1968	O
,	O
although	O
the	O
implementation	O
was	O
probably	O
completed	O
before	O
Wirth	O
left	O
Stanford	O
in	O
1967	O
.	O
</s>
<s>
PL/360	B-Language
is	O
a	O
one	O
pass	O
compiler	B-Language
with	O
a	O
syntax	O
similar	O
to	O
ALGOL	B-Language
that	O
provides	O
facilities	O
for	O
specifying	O
exact	O
machine	B-Language
code	I-Language
(	O
language	O
)	O
instructions	O
and	O
registers	O
similar	O
to	O
assembly	B-Language
language	I-Language
,	O
but	O
also	O
provides	O
features	O
commonly	O
found	O
in	O
high-level	B-Language
programming	I-Language
languages	I-Language
,	O
such	O
as	O
complex	O
arithmetic	O
expressions	O
and	O
control	O
structures	O
.	O
</s>
<s>
Wirth	O
used	O
PL360	B-Language
to	O
create	O
ALGOL	B-Language
W	I-Language
.	O
</s>
<s>
Individual	O
System/360	B-Application
instructions	O
can	O
be	O
generated	O
inline	O
using	O
the	O
PL360	B-Language
"	O
function	O
statement	O
"	O
that	O
defined	O
an	O
instruction	O
by	O
format	O
and	O
operation	O
code	O
.	O
</s>
<s>
Wirth	O
was	O
at	O
Stanford	O
between	O
1963	O
and	O
1967	O
,	O
during	O
the	O
earlier	O
part	O
of	O
which	O
he	O
was	O
developing	O
his	O
Euler	B-Language
compiler	B-Language
and	O
interpreter	O
,	O
the	O
sources	O
of	O
which	O
are	O
dated	O
1965	O
.	O
</s>
<s>
Also	O
in	O
1965	O
,	O
Stanford	O
updated	O
their	O
drum	B-General_Concept
memory	I-General_Concept
based	O
Burroughs	B-Device
large	I-Device
systems	I-Device
B5000	O
to	O
a	O
disk	B-Device
storage	I-Device
based	O
B5500	O
.	O
</s>
<s>
Since	O
the	O
target	O
IBM	B-Application
S/360	I-Application
(	O
which	O
was	O
to	O
replace	O
an	O
existing	O
IBM	B-Device
7090	I-Device
)	O
was	O
not	O
installed	O
until	O
1967	O
,	O
the	O
initial	O
implementation	O
of	O
PL360	B-Language
was	O
written	O
in	O
ALGOL	B-Language
and	O
tested	O
on	O
Stanford	O
's	O
B5500	O
.	O
</s>
<s>
Once	O
working	O
,	O
the	O
compiler	B-Language
was	O
then	O
recoded	O
in	O
PL360	B-Language
,	O
recompiled	B-Language
on	O
the	O
Burroughs	O
system	O
,	O
and	O
moved	O
as	O
a	O
binary	O
file	O
to	O
the	O
S/360	B-Application
.	O
</s>
<s>
The	O
B5500	O
is	O
programmed	O
in	O
a	O
high-level	O
ALGOL-derived	O
language	O
Executive	B-Language
Systems	I-Language
Problem	I-Language
Oriented	I-Language
Language	I-Language
(	O
ESPOL	B-Language
)	O
,	O
and	O
PL360	B-Language
was	O
intended	O
to	O
bring	O
a	O
comparable	O
facility	O
to	O
the	O
IBM	O
mainframe	O
architecture	O
,	O
although	O
it	O
was	O
lacking	O
major	O
facilities	O
of	O
both	O
Assembler	B-Language
F	O
and	O
ESPOL	B-Language
.	O
</s>
<s>
This	O
intent	O
was	O
largely	O
ignored	O
,	O
with	O
programmers	O
continuing	O
to	O
use	O
implementations	O
of	O
IBM	O
's	O
macro	B-Language
assemblers	I-Language
.	O
</s>
<s>
However	O
,	O
in	O
the	O
early	O
1970s	O
,	O
PL360	B-Language
was	O
extended	O
to	O
provide	O
more	O
capabilities	O
,	O
and	O
was	O
the	O
programming	O
language	O
of	O
choice	O
for	O
developing	O
Stanford	O
Physics	O
Information	O
Retrieval	O
System	O
(	O
SPIRES	O
)	O
,	O
Stanford	O
's	O
Database	O
Management	O
System	O
.	O
</s>
