<s>
is	O
a	O
mail	O
notification	O
system	O
for	O
Unix	B-Application
.	O
</s>
<s>
The	O
biff	B-Device
utility	O
was	O
the	O
user	O
interface	O
used	O
to	O
change	O
notification	O
preferences	O
.	O
</s>
<s>
The	O
actual	O
act	O
of	O
notifying	O
the	O
user	O
was	O
performed	O
by	O
a	O
daemon	B-Operating_System
called	O
(	O
short	O
for	O
"	O
communications	O
satellite	O
"	O
)	O
.	O
</s>
<s>
The	O
daemon	B-Operating_System
received	O
messages	O
via	O
UDP	B-Protocol
describing	O
the	O
update	O
to	O
the	O
mailbox	O
,	O
and	O
would	O
then	O
inform	O
the	O
user	O
of	O
the	O
new	O
message	O
.	O
</s>
<s>
The	O
general	O
idea	O
of	O
the	O
incoming	O
mail	O
alert	O
has	O
remained	O
very	O
popular	O
even	O
as	O
the	O
original	O
biff	B-Device
and	O
comsat	O
have	O
been	O
almost	O
completely	O
abandoned	O
.	O
</s>
<s>
The	O
concept	O
also	O
extends	O
outside	O
the	O
Unix	B-Application
world	O
—	O
the	O
AOL	O
"	O
You	O
've	O
got	O
mail	O
"	O
voice	O
could	O
be	O
seen	O
as	O
a	O
talking	O
biff	B-Device
.	O
</s>
<s>
was	O
written	O
by	O
John	O
Foderero	O
for	O
4.0BSD	B-Operating_System
.	O
</s>
