<s>
Mork	B-Application
is	O
a	O
computer	O
file	O
format	O
used	O
by	O
several	O
email	B-Protocol
clients	I-Protocol
and	O
web	B-Application
browsers	I-Application
produced	O
by	O
Netscape	O
,	O
and	O
later	O
,	O
Mozilla	B-Operating_System
Foundation	I-Operating_System
.	O
</s>
<s>
It	O
was	O
developed	O
by	O
David	B-Application
McCusker	I-Application
with	O
the	O
aim	O
of	O
creating	O
a	O
minimal	O
database	O
replacement	O
that	O
would	O
be	O
reliable	O
,	O
flexible	O
,	O
and	O
efficient	O
,	O
and	O
use	O
a	O
file	O
format	O
close	O
to	O
plain	O
text	O
.	O
</s>
<s>
The	O
format	O
was	O
named	O
after	O
the	O
character	O
Mork	B-Application
from	O
the	O
TV	O
show	O
Mork	B-Application
&	O
Mindy	O
.	O
</s>
<s>
The	O
Mork	B-Application
format	O
was	O
used	O
in	O
most	O
Mozilla-based	O
projects	O
,	O
including	O
the	O
Mozilla	O
browser	B-Application
suite	O
,	O
SeaMonkey	B-Language
,	O
Firefox	B-Application
,	O
and	O
Thunderbird	B-Application
.	O
</s>
<s>
In	O
Firefox	B-Application
,	O
it	O
was	O
used	O
for	O
browsing	O
history	O
data	O
and	O
form	O
history	O
data	O
.	O
</s>
<s>
In	O
Thunderbird	B-Application
,	O
it	O
is	O
still	O
used	O
for	O
many	O
things	O
,	O
such	O
as	O
address	O
book	O
data	O
(	O
.mab	O
files	O
)	O
and	O
the	O
mail	O
folder	O
summaries	O
(	O
.msf	O
files	O
)	O
.	O
</s>
<s>
Mork	B-Application
has	O
many	O
suboptimal	O
properties	O
.	O
</s>
<s>
For	O
example	O
,	O
despite	O
the	O
aim	O
of	O
efficiency	O
,	O
storing	O
Unicode	O
text	O
takes	O
three	O
or	O
six	O
bytes	B-Application
per	O
character	O
.	O
</s>
<s>
The	O
file	O
format	O
has	O
been	O
severely	O
criticized	O
by	O
Jamie	B-Operating_System
Zawinski	I-Operating_System
,	O
a	O
former	O
Netscape	O
engineer	O
.	O
</s>
<s>
In	O
response	O
,	O
McCusker	O
stated	O
that	O
the	O
problems	O
with	O
Mork	B-Application
resulted	O
from	O
"	O
conflicting	O
requirements	O
"	O
and	O
that	O
he	O
merely	O
fixed	O
scalability	O
issues	O
in	O
bad	O
code	O
he	O
"	O
inherited	O
"	O
.	O
</s>
<s>
The	O
Register	O
lambasted	O
the	O
Mork	B-Application
database	O
with	O
their	O
article	O
"	O
Why	O
has	O
Thunderbird	B-Application
turned	O
into	O
a	O
turkey	O
?	O
"	O
</s>
<s>
MozStorage	O
is	O
based	O
on	O
the	O
SQLite	B-Language
database	O
.	O
</s>
<s>
Beginning	O
with	O
Firefox	B-Application
3.0	O
,	O
Firefox	B-Application
uses	O
it	O
for	O
its	O
history	O
,	O
form	O
history	O
and	O
bookmark	O
data	O
.	O
</s>
<s>
The	O
storage	O
engine	O
was	O
also	O
included	O
in	O
Firefox	B-Application
2.0	O
,	O
but	O
only	O
for	O
use	O
with	O
extensions	O
.	O
</s>
<s>
Mork	B-Application
was	O
completely	O
removed	O
from	O
Firefox	B-Application
in	O
2011	O
.	O
</s>
<s>
Plans	O
existed	O
for	O
Mork	B-Application
to	O
be	O
replaced	O
with	O
MozStorage	O
in	O
Thunderbird	B-Application
3.0.	O
,	O
but	O
as	O
of	O
2023	O
still	O
used	O
the	O
Mork	B-Application
file	O
format	O
.	O
</s>
<s>
As	O
of	O
2012	O
,	O
SeaMonkey	B-Language
used	O
Mork	B-Application
for	O
at	O
least	O
its	O
POP	O
and	O
IMAP	O
mail	O
folders	O
indexes	O
.	O
</s>
