<s>
SQ	B-Application
(	O
squeeze	O
)	O
is	O
a	O
computer	O
program	O
,	O
devised	O
by	O
Richard	O
(	O
Dick	O
)	O
Greenlaw	O
circa	O
1981	O
,	O
which	O
was	O
used	O
in	O
the	O
early	O
1980s	O
on	O
both	O
DOS	B-Device
and	O
CP/M	B-Application
computer	O
systems	O
to	O
compress	O
files	O
so	O
they	O
use	O
less	O
space	O
.	O
</s>
<s>
Files	O
compressed	O
by	O
SQ	B-Application
are	O
identified	O
by	O
changing	O
the	O
middle	O
initial	O
of	O
the	O
extension	O
to	O
"	O
Q	O
"	O
,	O
so	O
that	O
text	O
files	O
ended	O
with	O
the	O
extension	O
,	O
executable	O
files	O
ended	O
with	O
the	O
extension	O
or	O
,	O
documents	O
with	O
,	O
etc	O
.	O
</s>
<s>
SQ	B-Application
used	O
static	B-General_Concept
Huffman	I-General_Concept
coding	I-General_Concept
as	O
the	O
compression	O
algorithm	O
.	O
</s>
<s>
Groups	O
of	O
files	O
were	O
often	O
combined	O
into	O
an	O
archive	O
using	O
the	O
LU	O
program	O
,	O
which	O
created	O
.LBR	B-Application
files	O
containing	O
all	O
the	O
files	O
needed	O
for	O
a	O
particular	O
group	O
,	O
such	O
as	O
all	O
the	O
files	O
needed	O
to	O
install	O
an	O
application	O
.	O
</s>
<s>
Typically	O
such	O
files	O
were	O
either	O
individually	O
compressed	O
(	O
because	O
LU	O
did	O
not	O
compress	O
files	O
)	O
or	O
the	O
LBR	B-Application
archive	O
was	O
itself	O
compressed	O
with	O
SQ	B-Application
(	O
similarly	O
to	O
the	O
use	O
of	O
tar	B-Application
and	O
gzip	B-Application
together	O
)	O
.	O
</s>
<s>
With	O
the	O
development	O
of	O
the	O
ARC	B-Application
program	O
(	O
which	O
combined	O
both	O
compression	O
and	O
archiving	O
into	O
one	O
program	O
)	O
and	O
its	O
ARC	B-Application
archive	O
file	O
format	O
,	O
SQ	B-Application
essentially	O
became	O
obsolete	O
on	O
most	O
systems	O
,	O
except	O
CP/M	B-Application
,	O
which	O
lacked	O
an	O
ARC	B-Application
port	O
for	O
several	O
years	O
.	O
</s>
<s>
On	O
CP/M	B-Application
systems	O
,	O
the	O
CRUNCH	O
compression	O
program	O
was	O
written	O
to	O
implement	O
the	O
LZW	B-Algorithm
algorithm	I-Algorithm
(	O
as	O
ARC	B-Application
did	O
)	O
and	O
plug	O
the	O
gap	O
.	O
</s>
