<s>
Lempel	B-Algorithm
–	I-Algorithm
Ziv	I-Algorithm
–	I-Algorithm
Stac	I-Algorithm
(	O
LZS	O
,	O
or	O
Stac	B-Algorithm
compression	I-Algorithm
or	O
Stacker	O
compression	O
)	O
is	O
a	O
lossless	B-Algorithm
data	I-Algorithm
compression	I-Algorithm
algorithm	O
that	O
uses	O
a	O
combination	O
of	O
the	O
LZ77	O
sliding-window	O
compression	O
algorithm	O
and	O
fixed	O
Huffman	B-General_Concept
coding	I-General_Concept
.	O
</s>
<s>
It	O
was	O
originally	O
developed	O
by	O
Stac	O
Electronics	O
for	O
tape	O
compression	O
,	O
and	O
subsequently	O
adapted	O
for	O
hard	B-General_Concept
disk	I-General_Concept
compression	I-General_Concept
and	O
sold	O
as	O
the	O
Stacker	O
disk	B-General_Concept
compression	I-General_Concept
software	O
.	O
</s>
<s>
LZS	O
is	O
specified	O
in	O
the	O
Cisco	B-Protocol
IOS	I-Protocol
stack	O
.	O
</s>
<s>
In	O
1993	O
–	O
94	O
,	O
Stac	O
Electronics	O
successfully	O
sued	O
Microsoft	O
for	O
infringement	O
of	O
LZS	O
patents	O
in	O
the	O
DoubleSpace	B-General_Concept
disk	B-General_Concept
compression	I-General_Concept
program	O
included	O
with	O
MS-DOS	O
6.0	O
.	O
</s>
