<s>
Screen	B-Application
Design	I-Application
Aid	I-Application
(	O
SDA	O
)	O
is	O
a	O
utility	O
for	O
the	O
IBM	B-Device
System/34	I-Device
and	O
System/36	B-Device
midrange	B-Device
computers	I-Device
.	O
</s>
<s>
The	O
System/38	B-Device
,	O
and	O
IBM	B-Application
i	I-Application
platforms	O
also	O
have	O
a	O
utility	O
Screen	B-Application
Design	I-Application
Aid	I-Application
,	O
but	O
its	O
syntax	O
and	O
functionality	O
are	O
different	O
.	O
</s>
<s>
S/34	O
and	O
S/36	B-Device
applications	O
usually	O
involve	O
the	O
operator	O
to	O
a	O
critical	O
degree	O
,	O
whether	O
accepting	O
the	O
bulk	O
of	O
input	O
through	O
display	O
stations	O
or	O
controlling	O
them	O
.	O
</s>
<s>
The	O
System/36	B-Device
version	O
of	O
SDA	O
gained	O
the	O
H	O
specification	O
,	O
which	O
describes	O
the	O
displays	O
used	O
when	O
the	O
operator	O
presses	O
the	O
"	O
Help	O
"	O
key	O
.	O
</s>
<s>
If	O
"	O
Help	O
"	O
was	O
not	O
coded	O
at	O
all	O
,	O
a	O
keyboard	O
error	O
occurs	O
,	O
stating	O
that	O
the	O
Help	B-Protocol
key	I-Protocol
is	O
not	O
allowed	O
now	O
.	O
</s>
<s>
When	O
the	O
IBM	B-Device
System/34	I-Device
was	O
sold	O
,	O
a	O
common	O
monitor	O
would	O
be	O
a	O
monochrome	O
12-inch	O
IBM	O
5251	O
;	O
in	O
the	O
System/36	B-Device
heyday	O
,	O
a	O
common	O
monitor	O
would	O
be	O
the	O
12-inch	O
IBM	O
5291	O
or	O
the	O
color	O
14-inch	O
IBM	O
3486	O
.	O
</s>
<s>
Later	O
in	O
the	O
S/36	B-Device
life	O
,	O
third	O
parties	O
began	O
to	O
rise	O
in	O
popularity	O
with	O
such	O
names	O
as	O
IIS	O
,	O
Decision	O
Data	O
,	O
and	O
Emerald	O
.	O
</s>
<s>
Not	O
only	O
do	O
the	O
third-party	O
monitors	O
cost	O
much	O
less	O
,	O
they	O
offer	O
multiple	O
session	O
capability	O
,	O
programmable	O
color	O
palettes	O
,	O
larger	O
display	O
areas	O
,	O
and	O
a	O
direct	O
PC	O
printer	B-Device
port	I-Device
which	O
allows	O
S/36	B-Device
users	O
to	O
access	O
inexpensive	O
inkjet	O
printers	O
without	O
a	O
separate	O
adapter	O
.	O
</s>
<s>
All	O
S/34	O
and	O
S/36	B-Device
display	O
stations	O
use	O
5250	O
protocol	O
;	O
S/34	O
allows	O
either	O
960-character	O
displays	O
or	O
1920-character	O
displays	O
;	O
S/36	B-Device
allows	O
either	O
1920-character	O
displays	O
or	O
(	O
rare	O
)	O
3564-character	O
displays	O
.	O
</s>
<s>
SDA	O
is	O
used	O
to	O
build	O
display	O
formats	O
which	O
are	O
similar	O
to	O
the	O
Microsoft	B-Application
Access	I-Application
convention	O
of	O
forms	O
.	O
</s>
