<s>
A	O
system	B-Language
programming	I-Language
language	I-Language
is	O
a	O
programming	O
language	O
used	O
for	O
system	B-Application
programming	I-Application
;	O
such	O
languages	O
are	O
designed	O
for	O
writing	O
system	B-Application
software	I-Application
,	O
which	O
usually	O
requires	O
different	O
development	O
approaches	O
when	O
compared	O
with	O
application	O
software	O
.	O
</s>
<s>
Examples	O
of	O
such	O
languages	O
include	O
ALGOL	B-Language
and	O
Pascal	B-Application
.	O
</s>
<s>
System	B-Application
languages	I-Application
,	O
in	O
contrast	O
,	O
are	O
designed	O
not	O
for	O
compatibility	O
,	O
but	O
for	O
performance	O
and	O
ease	O
of	O
access	O
to	O
the	O
underlying	O
hardware	O
while	O
still	O
providing	O
high-level	O
programming	O
concepts	O
like	O
structured	B-Language
programming	I-Language
.	O
</s>
<s>
Examples	O
include	O
SPL	B-Language
and	O
ESPOL	B-Language
,	O
both	O
of	O
which	O
are	O
similar	O
to	O
ALGOL	B-Language
in	O
syntax	O
but	O
tuned	O
to	O
their	O
respective	O
platforms	O
.	O
</s>
<s>
Others	O
are	O
cross-platform	O
but	O
designed	O
to	O
work	O
close	O
to	O
the	O
hardware	O
,	O
like	O
BLISS	B-Language
,	O
JOVIAL	B-Language
and	O
BCPL	B-Language
.	O
</s>
<s>
The	O
canonical	O
example	O
is	O
C	B-Language
,	O
which	O
is	O
used	O
widely	O
for	O
both	O
system	O
and	O
application	O
programming	O
.	O
</s>
<s>
Some	O
modern	O
languages	O
also	O
do	O
this	O
such	O
as	O
Rust	B-Application
and	O
Swift	B-Application
.	O
</s>
<s>
In	O
contrast	O
with	O
application	O
languages	O
,	O
system	B-Language
programming	I-Language
languages	I-Language
typically	O
offer	O
more-direct	O
access	O
to	O
the	O
physical	O
hardware	O
of	O
the	O
machine	O
:	O
an	O
archetypical	O
system	B-Language
programming	I-Language
language	I-Language
in	O
this	O
sense	O
was	O
BCPL	B-Language
.	O
</s>
<s>
System	B-Language
programming	I-Language
languages	I-Language
often	O
lack	O
built-in	O
input/output	B-General_Concept
(	O
I/O	B-General_Concept
)	O
facilities	O
because	O
a	O
system-software	O
project	O
usually	O
develops	O
its	O
own	O
I/O	B-General_Concept
mechanisms	O
or	O
builds	O
on	O
basic	O
monitor	O
I/O	B-General_Concept
or	O
screen	O
management	O
facilities	O
.	O
</s>
<s>
The	O
distinction	O
between	O
languages	O
used	O
for	O
system	B-Application
programming	I-Application
and	O
application	O
programming	O
became	O
blurred	O
over	O
time	O
with	O
the	O
widespread	O
popularity	O
of	O
PL/I	B-Language
,	O
C	B-Language
and	O
Pascal	B-Application
.	O
</s>
<s>
The	O
earliest	O
system	B-Application
software	I-Application
was	O
written	O
in	O
assembly	B-Language
language	I-Language
primarily	O
because	O
there	O
was	O
no	O
alternative	O
,	O
but	O
also	O
for	O
reasons	O
including	O
efficiency	O
of	O
object	O
code	O
,	O
compilation	B-Language
time	O
,	O
and	O
ease	O
of	O
debugging	O
.	O
</s>
<s>
Application	O
languages	O
such	O
as	O
FORTRAN	B-Application
were	O
used	O
for	O
system	B-Application
programming	I-Application
,	O
although	O
they	O
usually	O
still	O
required	O
some	O
routines	O
to	O
be	O
written	O
in	O
assembly	B-Language
language	I-Language
.	O
</s>
<s>
Mid-level	O
languages	O
"	O
have	O
much	O
of	O
the	O
syntax	O
and	O
facilities	O
of	O
a	O
higher	O
level	O
language	O
,	O
but	O
also	O
provide	O
direct	O
access	O
in	O
the	O
language	O
(	O
as	O
well	O
as	O
providing	O
assembly	B-Language
language	I-Language
)	O
to	O
machine	O
features.	O
"	O
</s>
<s>
The	O
earliest	O
of	O
these	O
was	O
ESPOL	B-Language
on	O
Burroughs	O
mainframes	O
in	O
about	O
1960	O
,	O
followed	O
by	O
Niklaus	O
Wirth	O
's	O
PL360	B-Language
(	O
first	O
written	O
on	O
a	O
Burroughs	O
system	O
as	O
a	O
cross	B-Application
compiler	I-Application
)	O
,	O
which	O
had	O
the	O
general	O
syntax	O
of	O
ALGOL	B-Language
60	I-Language
but	O
whose	O
statements	O
directly	O
manipulated	O
CPU	O
registers	O
and	O
memory	O
.	O
</s>
<s>
Other	O
languages	O
in	O
this	O
category	O
include	O
MOL-360	B-Language
and	O
PL/S	B-Language
.	O
</s>
<s>
As	O
an	O
example	O
,	O
a	O
typical	O
PL360	B-Language
statement	O
is	O
R9	O
:=	O
R8	O
and	O
R7	O
shll	O
8	O
or	O
R6	O
,	O
signifying	O
that	O
registers	O
8	O
and	O
7	O
should	O
be	O
and'ed	O
together	O
,	O
the	O
result	O
shifted	O
left	O
8	O
bits	O
,	O
the	O
result	O
of	O
that	O
or'ed	O
with	O
the	O
contents	O
of	O
register	O
6	O
,	O
and	O
the	O
final	O
result	O
placed	O
into	O
register	O
9	O
.	O
</s>
<s>
While	O
PL360	B-Language
is	O
at	O
the	O
semantic	O
level	O
of	O
assembly	B-Language
language	I-Language
,	O
another	O
kind	O
of	O
system	B-Language
programming	I-Language
language	I-Language
operates	O
at	O
a	O
higher	O
semantic	O
level	O
,	O
but	O
has	O
specific	O
extensions	O
designed	O
to	O
make	O
the	O
language	O
suitable	O
for	O
system	B-Application
programming	I-Application
.	O
</s>
<s>
An	O
early	O
example	O
of	O
this	O
kind	O
of	O
language	O
is	O
LRLTRAN	O
,	O
which	O
extended	O
Fortran	B-Application
with	O
features	O
for	O
character	O
and	O
bit	O
manipulation	O
,	O
pointers	O
,	O
and	O
directly	O
addressed	O
jump	O
tables	O
.	O
</s>
<s>
Subsequently	O
,	O
languages	O
such	O
as	O
C	B-Language
were	O
developed	O
,	O
where	O
the	O
combination	O
of	O
features	O
was	O
sufficient	O
to	O
write	O
system	B-Application
software	I-Application
,	O
and	O
a	O
compiler	B-Language
could	O
be	O
developed	O
that	O
generated	O
efficient	O
object	O
programs	O
on	O
modest	O
hardware	O
.	O
</s>
<s>
Such	O
a	O
language	O
generally	O
omits	O
features	O
that	O
cannot	O
be	O
implemented	O
efficiently	O
,	O
and	O
adds	O
a	O
small	O
number	O
of	O
machine-dependent	O
features	O
needed	O
to	O
access	O
specific	O
hardware	O
abilities	O
;	O
inline	B-Language
assembly	I-Language
code	O
,	O
such	O
as	O
C	B-Language
's	O
statement	O
,	O
is	O
often	O
used	O
for	O
this	O
purpose	O
.	O
</s>
<s>
Although	O
many	O
such	O
languages	O
were	O
developed	O
,	O
C	B-Language
and	O
C++	B-Language
are	O
the	O
ones	O
which	O
survived	O
.	O
</s>
<s>
System	B-Language
Programming	I-Language
Language	I-Language
(	O
SPL	B-Language
)	O
is	O
also	O
the	O
name	O
of	O
a	O
specific	O
language	O
on	O
the	O
HP	B-Device
3000	I-Device
computer	O
series	O
,	O
used	O
for	O
its	O
operating	O
system	O
HP	B-Operating_System
Multi-Programming	I-Operating_System
Executive	I-Operating_System
(	O
MPE	O
)	O
,	O
and	O
other	O
parts	O
of	O
its	O
system	B-Application
software	I-Application
.	O
</s>
<s>
Language	O
Originator	O
Birth	O
date	O
Influenced	O
by	O
Used	O
for	O
ESPOL	B-Language
Burroughs	O
Corporation	O
1961	O
ALGOL	B-Language
60	I-Language
MCP	B-Application
PL/I	B-Language
IBM	O
,	O
SHARE	O
1964	O
ALGOL	B-Language
,	O
FORTRAN	B-Application
,	O
some	O
COBOL	O
Multics	B-Application
PL/S	B-Language
IBM	O
1960	O
's	O
PL/I	B-Language
OS/360	B-Application
PL360	B-Language
Niklaus	O
Wirth	O
1968	O
ALGOL	B-Language
60	I-Language
ALGOL	B-Language
W	I-Language
Pascal	B-Application
Niklaus	O
Wirth	O
1970	O
ALGOL	B-Language
W	I-Language
Apollo	O
Computer	O
Aegis	O
,	O
Apple	O
MacApp	B-Operating_System
,	O
UCSD	O
p-System	O
BLISS	B-Language
Carnegie	O
Mellon	O
University	O
1970	O
ALGOL-PL/I	O
VMS	B-Operating_System
(	O
portions	O
)	O
Language	B-Device
for	I-Device
Systems	I-Device
Development	I-Device
(	O
LSD	O
)	O
R	O
.	O
Daniel	O
Bergeron	O
,	O
et	O
al	O
.	O
</s>
<s>
(	O
Brown	O
University	O
)	O
1971	O
PL/I	B-Language
C	B-Language
Dennis	O
Ritchie	O
1972	O
BCPL	B-Language
,	O
B	B-Language
(	O
programming	O
language	O
)	O
Most	O
operating	B-Operating_System
system	I-Operating_System
kernels	I-Operating_System
,	O
including	O
Unix-like	B-Operating_System
systems	I-Operating_System
NEWP	B-Language
Burroughs	O
1970	O
's	O
ESPOL	B-Language
,	O
ALGOL	B-Language
MCP	B-Application
PL/8	B-Language
IBM	O
1970	O
's	O
PL/I	B-Language
AIX	B-Application
PL-6	B-Language
Honeywell	O
,	O
Inc	O
.	O
1970	O
's	O
PL/I	B-Language
CP-6	B-Operating_System
SYMPL	B-Language
CDC	O
1970	O
's	O
JOVIAL	B-Language
NOS	B-Operating_System
subsystems	O
,	O
most	O
compilers	B-Language
,	O
FSE	O
editor	O
C++Bjarne	O
Stroustrup	O
1979	O
C	B-Language
,	O
Simula	B-Language
GUI	O
applications	O
(	O
Qt	B-Language
,	O
Windows	O
,	O
etc	O
.	O
</s>
