<s>
In	O
computers	O
,	O
a	O
printer	B-Application
driver	I-Application
or	O
a	O
print	B-Device
processor	O
is	O
a	O
piece	O
of	O
software	O
on	O
a	O
computer	O
that	O
converts	O
the	O
data	O
to	O
be	O
printed	O
to	O
a	O
format	O
that	O
a	O
printer	O
can	O
understand	O
.	O
</s>
<s>
The	O
purpose	O
of	O
printer	B-Application
drivers	I-Application
is	O
to	O
allow	O
applications	O
to	O
do	O
printing	O
without	O
being	O
aware	O
of	O
the	O
technical	O
details	O
of	O
each	O
printer	O
model	O
.	O
</s>
<s>
Printer	B-Application
drivers	I-Application
should	O
not	O
be	O
confused	O
with	O
print	B-Device
spoolers	I-Device
,	O
which	O
queue	B-Device
print	B-General_Concept
jobs	I-General_Concept
and	O
send	O
them	O
successively	O
to	O
a	O
printer	O
.	O
</s>
<s>
Unix	B-Application
and	O
other	O
Unix-like	B-Operating_System
systems	I-Operating_System
such	O
as	O
Linux	B-Application
and	O
OS	B-Operating_System
X	I-Operating_System
use	O
CUPS	O
(	O
short	O
for	O
Common	O
Unix	B-Application
Printing	O
System	O
)	O
,	O
a	O
modular	O
printing	O
system	O
for	O
Unix-like	B-Operating_System
computer	O
operating	O
systems	O
,	O
which	O
allows	O
a	O
computer	O
to	O
act	O
as	O
a	O
print	B-Application
server	I-Application
.	O
</s>
<s>
A	O
computer	O
running	O
CUPS	O
is	O
a	O
host	O
that	O
can	O
accept	O
print	B-General_Concept
jobs	I-General_Concept
from	O
client	O
computers	O
,	O
process	O
them	O
,	O
and	O
send	O
them	O
to	O
the	O
appropriate	O
printer	O
.	O
</s>
<s>
Printer	B-Application
drivers	I-Application
are	O
typically	O
implemented	O
as	O
filters	O
.	O
</s>
<s>
They	O
are	O
usually	O
named	O
the	O
front	O
end	O
of	O
the	O
printing	O
system	O
,	O
while	O
the	O
printer	B-Device
spoolers	I-Device
constitute	O
the	O
back	O
end	O
.	O
</s>
<s>
DOS	B-Device
supports	O
predefined	O
character	O
devices	O
PRN	B-Application
:	I-Application
,	O
LPT1	O
:	O
,	O
LPT2	O
:	O
and	O
LPT3	O
:	O
associated	O
with	O
parallel	O
printers	O
supported	O
in	O
the	O
system	O
.	O
</s>
<s>
Similarly	O
,	O
serial	O
printers	O
can	O
be	O
used	O
with	O
AUX	B-Application
:	I-Application
,	O
COM1	O
:	O
,	O
COM2	O
:	O
,	O
COM3	O
:	O
and	O
COM4	O
:	O
.	O
</s>
<s>
Users	O
can	O
use	O
commands	O
like	O
,	O
for	O
example	O
,	O
"	O
COPY	O
file1	O
LPT1	O
:	O
"	O
to	O
print	B-Device
the	O
content	O
of	O
a	O
file	O
to	O
a	O
printer	O
.	O
</s>
<s>
Therefore	O
,	O
this	O
method	O
of	O
printing	O
is	O
either	O
for	O
files	O
already	O
stored	O
in	O
the	O
corresponding	O
printer	O
's	O
language	O
or	O
for	O
generic	O
text	B-General_Concept
files	I-General_Concept
without	O
more	O
than	O
simple	O
line-oriented	O
formatting	O
.	O
</s>
<s>
DOS	B-Device
also	O
provides	O
a	O
dynamically	O
loadable	O
print	B-Device
spooler	I-Device
named	O
PRINT	B-Device
as	O
well	O
as	O
optional	O
support	O
to	O
support	O
screen	O
captures	O
also	O
in	O
graphics	O
mode	O
through	O
GRAPHICS	O
.	O
</s>
<s>
If	O
the	O
optional	O
character	O
device	O
driver	O
PRINTER.SYS	O
is	O
loaded	O
,	O
DOS	B-Device
provides	O
its	O
code	O
page	O
switching	O
support	O
also	O
for	O
the	O
associated	O
printersdifferent	O
types	O
of	O
dot	O
matrix	O
and	O
ink	O
jet	O
printers	O
are	O
supported	O
by	O
default	O
.	O
</s>
<s>
Beyond	O
this	O
,	O
there	O
are	O
no	O
system-wide	O
printer-specific	O
drivers	O
for	O
use	O
at	O
application	O
level	O
under	O
MS-DOS/PCDOS	O
.	O
</s>
<s>
Under	O
DR-DOS	B-Application
,	O
however	O
,	O
the	O
SCRIPT	O
command	O
can	O
be	O
loaded	O
to	O
run	O
in	O
the	O
background	O
in	O
order	O
to	O
intercept	O
and	O
convert	O
printer	O
output	O
from	O
applications	O
into	O
PostScript	B-Language
to	O
support	O
PS-capable	O
printers	O
also	O
by	O
applications	O
not	O
supporting	O
them	O
directly	O
.	O
</s>
<s>
a	O
word	B-General_Concept
processor	I-General_Concept
)	O
may	O
be	O
shipped	O
with	O
its	O
own	O
printer	B-Application
drivers	I-Application
,	O
which	O
were	O
essentially	O
descriptions	O
of	O
printer	O
escape	O
sequences	O
.	O
</s>
<s>
In	O
the	O
days	O
when	O
DOS	B-Device
was	O
widely	O
used	O
,	O
many	O
printers	O
had	O
emulation	O
modes	O
for	O
Epson	O
FX-80	O
and	O
IBM	O
Proprinter	O
commands	O
.	O
</s>
<s>
Many	O
more	O
recent	O
laser	O
printers	O
also	O
have	O
emulation	O
modes	O
for	O
HP	B-Language
PCL	I-Language
(	O
HP	O
LaserJet	O
)	O
or	O
PostScript	B-Language
printers	O
which	O
will	O
work	O
in	O
DOS	B-Device
.	O
</s>
<s>
On	O
Microsoft	B-Application
Windows	I-Application
systems	O
,	O
printer	B-Application
drivers	I-Application
make	O
use	O
of	O
GDI	B-Operating_System
(	O
Unidrv	O
or	O
PScript-based	O
)	O
or	O
XPS	B-Device
(	O
XPSDrv	O
)	O
.	O
</s>
<s>
Programs	O
then	O
use	O
the	O
same	O
standard	O
APIs	B-Application
to	O
draw	O
text	O
and	O
pictures	O
both	O
on	O
screen	O
and	O
on	O
paper	O
.	O
</s>
<s>
Printers	O
which	O
use	O
GDI	B-Operating_System
natively	O
are	O
commonly	O
referred	O
to	O
as	O
Winprinters	O
and	O
are	O
considered	O
incompatible	O
with	O
other	O
operating	O
systems	O
,	O
although	O
there	O
is	O
software	O
(	O
such	O
as	O
PrintFil	O
)	O
which	O
will	O
make	O
these	O
printers	O
work	O
in	O
a	O
DOS	B-Device
prompt	O
within	O
Windows	O
.	O
</s>
<s>
Win32	B-Library
APIs	I-Library
also	O
allow	O
applications	O
to	O
send	O
data	O
directly	O
to	O
the	O
spooler	B-Device
,	O
bypassing	O
the	O
printer	B-Application
driver	I-Application
;	O
however	O
,	O
few	O
applications	O
actually	O
use	O
this	O
option	O
.	O
</s>
<s>
The	O
printer	B-Application
driver	I-Application
is	O
usually	O
located	O
on	O
the	O
C:\Windows\System32\DriverStore\FileRepository	O
folder	O
on	O
a	O
Windows	O
machine	O
.	O
</s>
<s>
All	O
printer	B-Application
drivers	I-Application
were	O
stored	O
in	O
that	O
directory	O
,	O
and	O
covered	O
the	O
standard	O
printers	O
in	O
1985-1989	O
circa	O
,	O
included	O
Epson	O
FX	O
standard	O
driver	O
,	O
Xerox	O
4020	O
,	O
HP	O
,	O
etcetera	O
.	O
</s>
<s>
Any	O
Amiga	O
printer	B-Application
driver	I-Application
had	O
to	O
communicate	O
though	O
the	O
standard	O
Amiga	O
printer.device	O
(	O
the	O
default	O
standard	O
hardware	O
device	O
of	O
Amiga	O
dealing	O
with	O
printers	O
)	O
,	O
and	O
the	O
standard	O
parallel.device	O
(	O
which	O
controlled	O
parallel	O
port	O
)	O
and	O
the	O
driver	O
would	O
then	O
control	O
the	O
printer	O
on	O
its	O
own	O
.	O
</s>
<s>
Amiga	O
printer	B-Application
drivers	I-Application
were	O
an	O
innovation	O
for	O
their	O
time	O
.	O
</s>
<s>
They	O
had	O
the	O
ability	O
to	O
print	B-Device
up	O
to	O
4096	O
colors	O
.	O
</s>
<s>
Amiga	O
also	O
had	O
support	O
for	O
a	O
virtual	O
device	O
"	O
PRT	O
:	O
"	O
to	O
refer	O
to	O
printer.device	O
so	O
,	O
for	O
example	O
the	O
command	O
"	O
COPY	O
file	O
TO	O
PRT	O
:	O
"	O
caused	O
the	O
file	O
to	O
be	O
printed	O
directly	O
bypassing	O
parallel.device	O
and	O
the	O
default	O
printer	B-Application
driver	I-Application
.	O
</s>
<s>
The	O
printer	B-Application
driver	I-Application
then	O
translated	O
these	O
standard	O
sequences	O
into	O
the	O
special	O
sequences	O
a	O
certain	O
printer	O
understands	O
.	O
</s>
<s>
This	O
function	O
is	O
generally	O
called	O
on	O
by	O
printer	B-Application
drivers	I-Application
to	O
send	O
their	O
buffer(s )	O
to	O
the	O
printer	O
.	O
</s>
<s>
Amiga	O
lacked	O
a	O
standard	O
Printer	B-Device
Spooler	I-Device
.	O
</s>
<s>
The	O
Printer	O
preferences	O
were	O
divided	O
in	O
three	O
main	O
panels	O
:	O
Prefs:Printer	O
which	O
selects	O
main	O
printer	O
and	O
other	O
basic	O
elements	O
such	O
as	O
"	O
Print	B-Device
Spacing	O
"	O
and	O
"	O
Paper	O
Size	O
"	O
.	O
</s>
<s>
PrinterPS	O
controlled	O
Postscript	B-Language
Printers	O
.	O
</s>
<s>
The	O
printer	B-Application
drivers	I-Application
surprisingly	O
remained	O
almost	O
same	O
of	O
Workbench	O
1.3	O
,	O
with	O
4096	O
limits	O
.	O
</s>
<s>
This	O
fact	O
led	O
Amiga	O
users	O
to	O
prefer	O
third	O
party	O
Printer	O
Systems	O
with	O
their	O
own	O
drivers	O
,	O
like	O
TurboPrint	B-Device
and	O
PrintStudio	O
,	O
which	O
introduced	O
not	O
only	O
recent	O
drivers	O
,	O
but	O
also	O
featured	O
a	O
functioning	O
Printer	B-Device
Spooler	I-Device
into	O
Amiga	O
,	O
and	O
featured	O
16	O
million	O
colors	O
printing	O
.	O
</s>
<s>
MorphOS	B-Operating_System
uses	O
a	O
special	O
version	O
of	O
TurboPrint	B-Device
to	O
pilot	O
recent	O
printers	O
.	O
</s>
<s>
Many	O
Amiga	O
programs	O
like	O
DTP	O
programs	O
as	O
PageStream	B-Device
featured	O
in	O
the	O
past	O
its	O
own	O
printer	B-Application
drivers	I-Application
.	O
</s>
<s>
The	O
embedded	O
firmware	O
of	O
a	O
printer	O
could	O
thus	O
eliminate	O
the	O
need	O
to	O
install	O
any	O
driver	O
on	O
a	O
computer	O
,	O
by	O
accepting	O
print	B-Device
data	O
in	O
a	O
general	O
purpose	O
format	O
(	O
e.g.	O
</s>
<s>
PDF	B-Application
)	O
via	O
a	O
networking	O
protocol	O
.	O
</s>
<s>
These	O
drivers	O
can	O
convert	O
print	B-Device
data	O
from	O
one	O
general	O
purpose	O
format	O
(	O
e.g.	O
</s>
<s>
PDF	B-Application
,	O
DVI	O
etc	O
)	O
to	O
another	O
general	O
purpose	O
format	O
(	O
e.g.	O
</s>
<s>
PS	B-Language
)	O
.	O
</s>
<s>
These	O
drivers	O
convert	O
print	B-Device
data	O
from	O
one	O
format	O
(	O
e.g.	O
</s>
<s>
PS	B-Language
)	O
to	O
a	O
final	O
device-specific	O
format	O
that	O
the	O
printer	O
hardware	O
can	O
process	O
and	O
create	O
a	O
print	B-Device
.	O
</s>
<s>
These	O
drivers	O
act	O
as	O
the	O
last	O
stage	O
in	O
delivering	O
a	O
print	B-General_Concept
job	I-General_Concept
to	O
the	O
printer	O
.	O
</s>
<s>
PPD	B-Language
is	O
a	O
popular	O
packaging	O
format	O
for	O
drivers	O
that	O
accept	O
Postscript	B-Language
data	O
or	O
PDF	B-Application
data	O
as	O
input	O
.	O
</s>
<s>
PostScript	B-Language
Printer	I-Language
Description	I-Language
file	O
Usually	O
the	O
operating	O
system	O
needs	O
to	O
know	O
the	O
characteristics	O
of	O
a	O
printer	O
.	O
</s>
<s>
The	O
PPD	B-Language
files	I-Language
are	O
the	O
normal	O
way	O
to	O
supply	O
this	O
information	O
.	O
</s>
<s>
They	O
have	O
the	O
advantage	O
of	O
being	O
system	O
independent	O
,	O
and	O
there	O
is	O
a	O
freely	O
available	O
large	O
database	O
of	O
them	O
,	O
Foomatic	B-Application
.	O
</s>
<s>
CUPS	O
filter	O
This	O
format	O
is	O
used	O
by	O
CUPS	O
on	O
Linux	B-Application
systems	O
.	O
</s>
