<s>
Peripheral	B-Application
Interchange	I-Application
Program	I-Application
(	O
PIP	B-Application
)	O
was	O
a	O
utility	O
to	O
transfer	O
files	O
on	O
and	O
between	O
devices	O
on	O
Digital	O
Equipment	O
Corporation	O
's	O
computers	O
.	O
</s>
<s>
It	O
was	O
first	O
implemented	O
on	O
the	O
PDP-6	B-Device
architecture	O
by	O
Harrison	O
"	O
Dit	O
"	O
Morse	O
early	O
in	O
the	O
1960s	O
.	O
</s>
<s>
It	O
was	O
subsequently	O
implemented	O
for	O
DEC	O
's	O
operating	O
systems	O
for	O
PDP-10	B-Device
,	O
PDP-11	B-Device
,	O
and	O
PDP-8	B-Device
architectures	O
.	O
</s>
<s>
In	O
the	O
1970s	O
and	O
1980s	O
Digital	O
Research	O
implemented	O
PIP	B-Application
on	O
CP/M	B-Application
and	O
MP/M	B-Operating_System
.	O
</s>
<s>
This	O
humorously	O
described	O
both	O
its	O
purpose	O
as	O
a	O
device-independent	O
file	B-Application
copying	I-Application
tool	O
and	O
the	O
difficulties	O
at	O
the	O
time	O
of	O
safely	O
copying	B-Application
files	I-Application
between	O
devices	O
.	O
</s>
<s>
using	O
the	O
left-arrow	O
character	O
from	O
the	O
ASCII-1963	O
character	O
set	O
that	O
the	O
Flexowriter	B-Application
keyboards	O
of	O
the	O
time	O
used	O
.	O
</s>
<s>
The	O
underscore	O
( _	O
)	O
character	O
,	O
which	O
was	O
in	O
the	O
same	O
ASCII	B-Protocol
character	I-Protocol
position	O
that	O
left-arrow	O
had	O
occupied	O
,	O
was	O
still	O
supported	O
to	O
separate	O
the	O
destination	O
and	O
source	O
specifications	O
.	O
</s>
<s>
These	O
consisted	O
of	O
a	O
device	B-Application
name	I-Application
,	O
typically	O
2	O
characters	O
for	O
device	O
type	O
such	O
as	O
DK	O
(	O
disk	O
)	O
,	O
LP	O
(	O
line	O
printer	O
)	O
,	O
MT	O
(	O
magnetic	O
tape	O
)	O
,	O
etc	O
.	O
</s>
<s>
Early	O
versions	O
of	O
VAX/VMS	B-Operating_System
implemented	O
certain	O
DCL	B-Operating_System
commands	O
,	O
such	O
as	O
DIRECTORY	B-Application
and	O
RENAME	B-Device
,	O
by	O
running	O
RSX-11M	B-Application
PIP	B-Application
in	O
compatibility	O
mode	O
.	O
</s>
<s>
This	O
usage	O
of	O
PIP	B-Application
was	O
replaced	O
by	O
VAX-specific	O
code	O
in	O
VAX/VMS	B-Operating_System
2.0	O
,	O
but	O
PIP	B-Application
remained	O
as	O
part	O
of	O
the	O
VAX-11	O
RSX	O
layered	O
product	O
for	O
VMS	B-Operating_System
.	O
</s>
<s>
As	O
late	O
as	O
the	O
mid	O
1980s	O
,	O
PIP	B-Application
was	O
still	O
in	O
common	O
use	O
on	O
TOPS-10	B-Operating_System
,	O
TOPS-20	B-Operating_System
and	O
PDP-11	B-Device
systems	O
.	O
</s>
<s>
Gary	O
Kildall	O
,	O
who	O
developed	O
CP/M	B-Application
and	O
MP/M	B-Operating_System
,	O
based	O
much	O
of	O
the	O
design	O
of	O
its	O
file	O
structure	O
and	O
command	B-Application
processor	O
on	O
operating	O
systems	O
from	O
Digital	O
Equipment	O
,	O
such	O
as	O
RSTS/E	B-Operating_System
for	O
the	O
PDP-11	B-Device
.	O
</s>
<s>
Besides	O
accessing	O
files	O
on	O
a	O
floppy	B-Device
disk	I-Device
,	O
the	O
PIP	B-Application
command	B-Application
in	O
CP/M	B-Application
could	O
also	O
transfer	O
data	O
to	O
and	O
from	O
the	O
following	O
"	O
special	B-Application
files	I-Application
"	O
:	O
</s>
<s>
These	O
were	O
not	O
true	O
device	B-Application
files	I-Application
,	O
however	O
,	O
because	O
their	O
handling	O
was	O
limited	O
to	O
PIP	B-Application
.	O
</s>
<s>
The	O
two	O
custom	O
devices	O
and	O
were	O
implemented	O
as	O
calls	O
to	O
fixed	O
locations	O
at	O
the	O
start	O
of	O
the	O
PIP	B-Application
program	O
;	O
the	O
intention	O
was	O
that	O
the	O
user	O
,	O
or	O
the	O
OEM	O
,	O
could	O
patch	O
these	O
locations	O
to	O
add	O
their	O
own	O
input	O
or	O
output	O
devices	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
usual	O
PIP	B-Application
destination	O
=	O
source	O
syntax	O
,	O
PIP	B-Application
under	O
CP/M	B-Application
still	O
allowed	O
the	O
old	O
PIP	B-Application
destination_source	O
form	O
.	O
</s>
<s>
This	O
behaviour	O
was	O
not	O
documented	O
,	O
and	O
CP/M	B-Application
generally	O
did	O
not	O
have	O
a	O
standard	O
for	O
which	O
characters	O
could	O
appear	O
in	O
file	O
names	O
;	O
therefore	O
other	O
programs	O
could	O
and	O
did	O
create	O
filenames	O
containing	O
underscore	O
characters	O
,	O
which	O
PIP	B-Application
could	O
not	O
handle	O
.	O
</s>
