<s>
Ada	B-Application
is	O
a	O
computer	O
virus	O
that	O
can	O
affect	O
any	O
of	O
the	O
DOS	B-Device
operating	O
systems	O
.	O
</s>
<s>
Ada	B-Application
was	O
first	O
discovered	O
in	O
1991	O
.	O
</s>
<s>
Ada	B-Application
virus	I-Application
was	O
first	O
discovered	O
in	O
Argentina	O
in	O
.	O
</s>
<s>
Ada	B-Application
is	O
a	O
memory	O
resident	O
virus	O
that	O
infects	O
files	O
.	O
</s>
<s>
The	O
Ada	B-Application
virus	I-Application
mainly	O
targets	O
.COM	O
files	O
,	O
specifically	O
COMMAND.COM	O
and	O
stays	O
in	O
the	O
memory	O
of	O
the	O
computer	O
it	O
infects	O
after	O
the	O
program	O
it	O
infected	O
executes	O
.	O
</s>
<s>
ADA	B-Application
VIRUS	I-Application
DISINI	O
!	O
</s>
<s>
Another	O
version	O
of	O
Ada	B-Application
has	O
these	O
text	O
strings	O
along	O
with	O
the	O
strings	O
BASURA	O
BASURA	O
repeated	O
numerous	O
times	O
.	O
</s>
<s>
Computers	O
infected	O
with	O
the	O
Ada	B-Application
virus	I-Application
often	O
have	O
a	O
slow	O
clicking	O
sound	O
emitting	O
from	O
their	O
speakers	O
;	O
this	O
clicking	O
may	O
sometimes	O
change	O
in	O
pitch	O
.	O
</s>
<s>
While	O
infected	O
with	O
the	O
Ada	B-Application
virus	I-Application
,	O
system	O
memory	O
measured	O
by	O
the	O
DOS	B-Device
CHKDSK	B-Device
decreases	O
by	O
21,296	O
bytes	O
to	O
21,312	O
bytes	O
.	O
</s>
<s>
There	O
is	O
only	O
one	O
way	O
to	O
infect	O
a	O
computer	O
with	O
the	O
Ada	B-Application
virus	I-Application
;	O
by	O
executing	O
an	O
infected	O
file	O
.	O
</s>
