<s>
ThunderBYTE	B-Application
Anti-Virus	B-Application
(	O
TBAV	B-Application
)	O
was	O
an	O
early	O
antivirus	B-Application
software	I-Application
product	O
.	O
</s>
<s>
It	O
was	O
mainly	O
designed	O
for	O
DOS	B-Device
,	O
but	O
there	O
were	O
also	O
versions	O
supporting	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
TBAV	B-Application
was	O
known	O
for	O
its	O
fast	O
scan	O
speed	O
,	O
heuristics-based	O
scanner	O
,	O
and	O
Anti-Vir.Dat	O
files	O
tracking	O
known-good	O
file	O
information	O
.	O
</s>
<s>
Originally	O
ThunderBYTE	B-Application
used	O
a	O
dedicated	O
ISA	B-Architecture
card	I-Architecture
to	O
provide	O
protection	O
before	O
the	O
operating	B-General_Concept
system	I-General_Concept
was	O
even	O
loaded	O
.	O
</s>
<s>
It	O
was	O
distributed	O
as	O
shareware	B-License
.	O
</s>
<s>
In	O
1998	O
,	O
TBAV	B-Application
was	O
sold	O
to	O
Norman	O
ASA	O
,	O
which	O
discontinued	O
ThunderBYTE	B-Application
as	O
a	O
product	O
.	O
</s>
