<s>
Shared	B-Language
Variables	I-Language
are	O
a	O
feature	O
of	O
the	O
programming	O
language	O
APL	B-Language
which	O
allows	O
APL	B-Language
programs	O
running	O
on	O
one	O
processor	O
to	O
share	O
information	O
with	O
another	O
processor	O
.	O
</s>
<s>
Although	O
originally	O
developed	O
for	O
mainframe	B-Architecture
computers	I-Architecture
,	O
Shared	B-Language
Variables	I-Language
were	O
also	O
used	O
in	O
personal	B-Device
computer	I-Device
implementations	O
of	O
APL	B-Language
.	O
</s>
<s>
Shared	B-Language
Variables	I-Language
could	O
be	O
used	O
to	O
control	O
peripheral	B-Device
devices	I-Device
,	O
or	O
to	O
communicate	O
with	O
external	O
files	O
,	O
database	O
management	O
systems	O
,	O
or	O
other	O
users	O
.	O
</s>
<s>
Shared	B-Language
Variables	I-Language
were	O
first	O
introduced	O
by	O
International	O
Business	O
Machines	O
Corporation	O
(	O
IBM	O
)	O
in	O
their	O
APL.SV	O
software	O
product	O
in	O
1973	O
,	O
and	O
are	O
still	O
available	O
,	O
in	O
APLs	B-Language
from	O
IBM	O
and	O
Dyalog	O
,	O
for	O
the	O
operating	O
systems	O
Linux	B-Application
and	O
Windows	B-Application
.	O
</s>
<s>
When	O
APL	B-Language
\360	I-Language
was	O
first	O
introduced	O
in	O
1968	O
,	O
there	O
were	O
no	O
built-in	O
means	O
by	O
which	O
a	O
user	O
could	O
directly	O
access	O
data	O
from	O
outside	O
of	O
the	O
APL	B-Language
system	O
.	O
</s>
<s>
Thus	O
,	O
starting	O
in	O
1969	O
,	O
IBM	O
developed	O
the	O
shared	B-Language
variable	I-Language
facility	O
.	O
</s>
<s>
Following	O
APL.SV	O
,	O
the	O
IBM	O
VS	O
APL	B-Language
and	O
APL2	O
program	O
products	O
also	O
supported	O
shared	B-Language
variables	I-Language
,	O
as	O
did	O
the	O
IBM	B-Device
5100	I-Device
line	O
of	O
computers	O
.	O
</s>
<s>
Shared	B-Language
Variable	I-Language
Processors	O
were	O
available	O
to	O
allow	O
APL	B-Language
access	O
to	O
the	O
following	O
:	O
</s>
<s>
In	O
the	O
early	O
1980s	O
,	O
I	O
.	O
P	O
.	O
Sharp	O
Associates	O
,	O
which	O
offered	O
a	O
rich	O
and	O
advanced	O
APL	B-Language
,	O
introduced	O
Shared	B-Language
Variables	I-Language
in	O
their	O
product	O
.	O
</s>
<s>
Many	O
of	O
the	O
Shared	B-Language
Variable	I-Language
Processors	O
available	O
for	O
IBM	O
products	O
were	O
also	O
written	O
for	O
Sharp	O
APL	B-Language
,	O
notably	O
TSIO	O
(	O
called	O
PJAM	O
)	O
,	O
AP124	O
,	O
AP126	O
,	O
and	O
AP127	O
.	O
</s>
<s>
Further	O
,	O
as	O
I	O
.	O
P	O
.	O
Sharp	O
also	O
offered	O
IPSANET	B-Protocol
which	O
allowed	O
in-house	O
clients	O
of	O
SHARP	O
APL	B-Language
to	O
be	O
connected	O
to	O
the	O
network	O
,	O
a	O
Network	O
Shared	B-Language
Variable	I-Language
Processor	O
(	O
NSVP	O
)	O
allowed	O
programs	O
from	O
one	O
mainframe	B-Architecture
site	O
to	O
access	O
another	O
.	O
</s>
<s>
Shared	B-Language
Variables	I-Language
were	O
one	O
technique	O
used	O
by	O
APL	B-Language
implementors	O
and	O
vendors	O
to	O
increase	O
the	O
richness	O
of	O
the	O
APL	B-Language
language	I-Language
,	O
doing	O
so	O
without	O
changing	O
the	O
core	O
implementation	O
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
more	O
powerful	O
personal	B-Device
computing	I-Device
,	O
the	O
exodus	O
of	O
the	O
APL	B-Language
user	O
community	O
to	O
smaller	O
computers	O
was	O
inevitable	O
.	O
</s>
<s>
APL	B-Language
was	O
first	O
available	O
on	O
Intel	B-General_Concept
8008	I-General_Concept
,	O
8080	B-General_Concept
,	O
and	O
Zilog	B-General_Concept
Z80	I-General_Concept
based	O
hardware	O
,	O
later	O
the	O
original	O
IBM	O
PC	O
,	O
and	O
as	O
of	O
2015	O
,	O
on	O
the	O
32	O
-	O
and	O
64-bit	O
Linux	B-Application
and	O
Windows	B-Application
workstations	O
.	O
</s>
<s>
Although	O
Dyalog	O
APL	B-Language
included	O
an	O
implementation	O
of	O
shared	B-Language
variables	I-Language
for	O
communication	O
with	O
the	O
now-deprecated	O
Microsoft	B-Application
Windows	I-Application
Dynamic	B-Operating_System
Data	I-Operating_System
Exchange	I-Operating_System
(	O
DDE	O
)	O
,	O
only	O
IBM	O
continued	O
to	O
use	O
Shared	B-Language
Variables	I-Language
as	O
a	O
means	O
to	O
supply	O
new	O
features	O
to	O
their	O
versions	O
of	O
the	O
APL2	O
language	O
for	O
non-mainframe	O
computers	O
.	O
</s>
<s>
Nearly	O
all	O
other	O
APL	B-Language
vendors	O
chose	O
to	O
implement	O
new	O
functions	O
,	O
such	O
as	O
access	O
to	O
Linux	B-Application
and	O
Windows	B-Application
native	O
features	O
,	O
graphical	B-Application
user	I-Application
interfaces	I-Application
,	O
presentation	O
graphics	O
,	O
database	O
management	O
system	O
interfaces	O
,	O
and	O
so	O
on	O
,	O
more	O
directly	O
in	O
their	O
respective	O
versions	O
of	O
the	O
APL	B-Language
language	I-Language
.	O
</s>
<s>
In	O
modern	O
non-IBM	O
APL	B-Language
implementations	O
,	O
the	O
Shared	B-Language
Variable	I-Language
interface	O
has	O
been	O
largely	O
supplanted	O
by	O
Component	B-Application
Object	I-Application
Model	I-Application
(	O
COM	O
)	O
,	O
ActiveX	B-Application
,	O
and	O
.NET	B-Application
Framework	I-Application
.	O
</s>
