<s>
Portable	B-Language
Standard	I-Language
Lisp	I-Language
(	O
PSL	O
)	O
is	O
a	O
programming	O
language	O
,	O
a	O
dialect	O
of	O
the	O
language	O
Lisp	B-Language
.	O
</s>
<s>
PSL	O
was	O
inspired	O
by	O
its	O
predecessor	O
,	O
Standard	O
Lisp	B-Language
and	O
the	O
Portable	B-Architecture
Lisp	B-Language
Compiler	B-Language
.	O
</s>
<s>
It	O
is	O
tail-recursive	B-Language
,	O
late	O
binding	O
(	O
or	O
dynamically	O
bound	O
)	O
,	O
and	O
was	O
developed	O
by	O
researchers	O
at	O
the	O
University	O
of	O
Utah	O
in	O
1980	O
,	O
which	O
released	O
PSL	O
3.1	O
;	O
development	O
was	O
handed	O
over	O
to	O
developers	O
at	O
Hewlett-Packard	O
in	O
1982	O
who	O
released	O
PSL	O
3.3	O
and	O
up	O
.	O
</s>
<s>
Portable	B-Language
Standard	I-Language
Lisp	I-Language
was	O
available	O
as	O
a	O
kit	O
containing	O
a	O
screen	B-Application
editor	I-Application
,	O
a	O
compiler	B-Language
,	O
and	O
an	O
interpreter	B-Application
for	O
several	O
hardware	O
and	O
operating	O
system	O
computing	B-Device
platforms	I-Device
,	O
including	O
Motorola	B-Device
68000	I-Device
series	I-Device
,	O
DECSYSTEM-20s	B-Device
,	O
Cray-1s	B-Device
,	O
VAX	B-Device
,	O
and	O
many	O
others	O
.	O
</s>
<s>
Its	O
main	O
modern	O
use	O
is	O
as	O
the	O
underlying	O
language	O
for	O
implementations	O
of	O
Reduce	B-Language
.	O
</s>
<s>
Like	O
most	O
older	O
Lisps	B-Language
,	O
in	O
the	O
first	O
step	O
,	O
PSL	O
compiles	B-Language
Lisp	B-Language
code	O
to	O
LAP	O
code	O
,	O
which	O
is	O
another	O
cross-platform	B-Operating_System
language	O
.	O
</s>
<s>
However	O
,	O
where	O
older	O
lisps	B-Language
mostly	O
compiled	B-Language
LAP	O
directly	O
to	O
assembly	B-Language
language	I-Language
or	O
some	O
architecture	O
dependent	O
intermediate	O
,	O
PSL	O
compiles	B-Language
the	O
LAP	O
to	O
C	B-Language
code	O
,	O
which	O
would	O
run	O
in	O
a	O
virtual	O
machine	O
language	O
;	O
so	O
programs	O
written	O
in	O
it	O
are	O
as	O
portable	B-Architecture
as	O
C	B-Language
in	O
principle	O
,	O
which	O
is	O
very	O
portable	B-Architecture
.	O
</s>
<s>
The	O
compiler	B-Language
was	O
written	O
in	O
PSL	O
or	O
a	O
more	O
primitive	O
dialect	O
named	O
System	O
Lisp	B-Language
or	O
SYSLISP	O
as	O
"	O
...	O
an	O
experiment	O
in	O
writing	O
a	O
production-quality	O
Lisp	B-Language
in	O
Lisp	B-Language
itself	O
as	O
much	O
as	O
possible	O
,	O
with	O
only	O
minor	O
amounts	O
of	O
code	O
written	O
by	O
hand	O
in	O
assembly	B-Language
language	I-Language
or	O
other	O
systems	O
languages.	O
"	O
</s>
<s>
so	O
the	O
whole	O
ensemble	O
could	O
bootstrap	B-Application
itself	O
,	O
and	O
improvements	O
to	O
the	O
compiler	B-Language
improved	O
the	O
compiler	B-Language
.	O
</s>
<s>
Some	O
later	O
releases	O
had	O
a	O
compatibility	O
package	O
for	O
Common	B-Language
Lisp	I-Language
,	O
but	O
this	O
is	O
not	O
sustained	O
in	O
the	O
modern	O
versions	O
.	O
</s>
<s>
Portable	B-Language
Standard	I-Language
Lisp	I-Language
has	O
fewer	O
features	O
than	O
other	O
Lisps	B-Language
,	O
such	O
as	O
Common	B-Language
Lisp	I-Language
,	O
and	O
some	O
people	O
found	O
it	O
unpleasant	O
to	O
use	O
.	O
</s>
<s>
Richard	O
P	O
.	O
Gabriel	O
wrote	O
in	O
his	O
popular	O
essay	O
Lisp	B-Language
:	O
Good	O
News	O
,	O
Bad	O
News	O
,	O
How	O
to	O
Win	O
Big	O
,	O
"	O
the	O
third	O
most	O
standard	O
Lisp	B-Language
was	O
Portable	B-Language
Standard	I-Language
Lisp	I-Language
,	O
which	O
ran	O
on	O
many	O
machines	O
,	O
but	O
very	O
few	O
people	O
wanted	O
to	O
use	O
it	O
;	O
"	O
.	O
</s>
