<s>
Sunday	O
is	O
a	O
computer	O
virus	O
(	O
program	O
file	O
virus	O
)	O
,	O
a	O
member	O
of	O
the	O
Jerusalem	B-Application
virus	I-Application
family	O
.	O
</s>
<s>
Sunday	O
is	O
a	O
standard	O
patched	O
Jerusalem	B-Application
variant	O
in	O
the	O
way	O
it	O
infects	O
files	O
.	O
</s>
<s>
It	O
is	O
a	O
directly	O
modified	O
version	O
of	O
the	O
original	O
Jerusalem.1803	O
.	O
</s>
<s>
Like	O
the	O
original	O
Jerusalem	B-Application
,	O
infected	O
files	O
occasionally	O
become	O
corrupted	O
.	O
</s>
<s>
Sunday	O
is	O
less	O
easily	O
identified	O
than	O
the	O
original	O
Jerusalem	B-Application
,	O
in	O
part	O
because	O
of	O
corrected	O
errors	O
and	O
in	O
part	O
because	O
its	O
payload	O
is	O
poorly	O
written	O
and	O
fails	O
to	O
execute	O
.	O
</s>
<s>
Unlike	O
the	O
original	O
Jerusalem	B-Application
,	O
files	O
will	O
not	O
be	O
infected	O
many	O
times	O
.	O
</s>
<s>
Interrupt	B-Application
21	O
will	O
be	O
hooked	O
.	O
</s>
<s>
This	O
is	O
to	O
print	O
the	O
previously	O
indicated	O
text	O
on	O
the	O
screen	O
and	O
then	O
delete	O
all	O
files	O
run	O
while	O
the	O
virus	O
is	O
memory	O
resident	O
,	O
as	O
the	O
original	O
Jerusalem	B-Application
did	O
every	O
Friday	O
the	O
13th	O
.	O
</s>
<s>
Like	O
all	O
DOS	B-Device
viruses	O
,	O
Sunday	O
suffered	O
with	O
the	O
debut	O
of	O
Windows	B-Application
.	O
</s>
