<s>
The	O
Doctor	B-Device
V64	I-Device
(	O
also	O
referred	O
to	O
simply	O
as	O
the	O
V64	O
)	O
is	O
a	O
development	O
and	O
backup	B-Device
device	I-Device
made	O
by	O
Bung	O
Enterprises	O
Ltd	O
that	O
is	O
used	O
in	O
conjunction	O
with	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
also	O
had	O
the	O
ability	O
to	O
play	O
video	O
CDs	O
and	O
audio	O
CDs	O
.	O
</s>
<s>
It	O
was	O
the	O
first	O
commercially-available	O
backup	B-Device
device	I-Device
for	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
unit	O
.	O
</s>
<s>
The	O
Partner	O
N64	B-Operating_System
development	O
kit	O
,	O
which	O
was	O
manufactured	O
by	O
Silicon	O
Graphics	O
and	O
sold	O
officially	O
by	O
Nintendo	O
,	O
was	O
a	O
comparatively	O
expensive	O
development	O
machine	O
.	O
</s>
<s>
The	O
CPU	B-General_Concept
of	O
the	O
V64	O
is	O
a	O
6502	B-General_Concept
,	O
and	O
the	O
operating	O
system	O
is	O
contained	O
in	O
a	O
BIOS	B-Operating_System
.	O
</s>
<s>
The	O
V64	O
unit	O
contains	O
a	O
CD-ROM	O
drive	O
which	O
sits	O
underneath	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
and	O
plugs	O
into	O
the	O
expansion	O
slot	O
on	O
the	O
underside	O
of	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
.	O
</s>
<s>
The	O
expansion	O
slot	O
is	O
essentially	O
a	O
mirror	O
image	O
of	O
the	O
cartridge	O
slot	O
on	O
the	O
top	O
of	O
the	O
unit	O
,	O
with	O
the	O
same	O
electrical	O
connections	O
;	O
thus	O
,	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
reads	O
data	O
from	O
the	O
Doctor	B-Device
V64	I-Device
in	O
the	O
same	O
manner	O
as	O
it	O
would	O
from	O
a	O
cartridge	O
plugged	O
into	O
the	O
normal	O
slot	O
.	O
</s>
<s>
In	O
order	O
to	O
get	O
around	O
Nintendo	O
's	O
lockout	O
chip	O
,	O
when	O
using	O
the	O
V64	O
,	O
a	O
game	O
cartridge	O
is	O
plugged	O
into	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
through	O
an	O
adaptor	O
which	O
connects	O
only	O
the	O
lockout	O
chip	O
.	O
</s>
<s>
Most	O
N64	B-Operating_System
games	O
are	O
saved	O
to	O
the	O
cart	O
itself	O
instead	O
of	O
external	O
memory	O
cards	O
.	O
</s>
<s>
These	O
devices	O
were	O
inserted	O
into	O
the	O
top-slot	O
of	O
the	O
N64	B-Operating_System
with	O
the	O
game	O
cartridge	O
being	O
then	O
inserted	O
into	O
the	O
top	O
of	O
them	O
to	O
just	O
provide	O
the	O
security	O
bypass	O
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
could	O
be	O
used	O
to	O
read	O
the	O
data	O
from	O
a	O
game	O
cartridge	O
and	O
transfer	O
the	O
data	O
to	O
a	O
PC	O
via	O
the	O
parallel	B-Device
port	I-Device
.	O
</s>
<s>
This	O
allowed	O
developers	O
and	O
homebrew	O
programmers	O
to	O
upload	O
their	O
game	O
images	O
to	O
the	O
Doctor	B-Device
V64	I-Device
without	O
having	O
to	O
create	O
a	O
CD	O
backup	O
each	O
time	O
.	O
</s>
<s>
Following	O
the	O
Doctor	B-Device
V64	I-Device
's	O
success	O
,	O
Bung	O
released	O
the	O
Doctor	B-Device
V64	I-Device
Jr.	O
in	O
December	O
1998	O
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
Jr.	O
has	O
no	O
CD	O
drive	O
and	O
plugs	O
into	O
the	O
normal	O
cartridge	O
slot	O
on	O
the	O
top	O
of	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
.	O
</s>
<s>
Data	O
is	O
loaded	O
into	O
the	O
Doctor	B-Device
V64	I-Device
Jr.	O
'	O
s	O
battery-backed	O
RAM	O
from	O
a	O
PC	O
via	O
a	O
parallel	B-Device
port	I-Device
connection	O
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
Jr.	O
has	O
up	O
to	O
512	O
megabits	O
(	O
64	O
MB	O
)	O
of	O
memory	O
storage	O
.	O
</s>
<s>
This	O
was	O
done	O
to	O
provide	O
for	O
future	O
Nintendo	B-Operating_System
64	I-Operating_System
carts	O
that	O
employed	O
larger	O
memory	O
storage	O
,	O
but	O
the	O
high	O
costs	O
associated	O
with	O
ordering	O
large	O
storage	O
carts	O
kept	O
this	O
occurrence	O
at	B-Device
a	O
minimum	O
.	O
</s>
<s>
Only	O
a	O
handful	O
of	O
512-megabit	O
games	O
were	O
released	O
for	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
system	O
.	O
</s>
<s>
In	O
1998	O
and	O
1999	O
,	O
there	O
was	O
a	O
homebrew	O
competition	O
known	O
as	O
"	O
Presence	O
of	O
Mind	O
"	O
(	O
POM	O
)	O
,	O
an	O
N64	B-Operating_System
demo	O
competition	O
led	O
by	O
dextrose.com	O
.	O
</s>
<s>
The	O
contest	O
consisted	O
of	O
submitting	O
a	O
user-developed	O
N64	B-Operating_System
program	O
,	O
game	O
,	O
or	O
utility	O
.	O
</s>
<s>
Bung	O
Enterprises	O
promoted	O
the	O
event	O
and	O
supplied	O
prizes	O
(	O
usually	O
Doctor	B-Device
V64	I-Device
related	O
accessories	O
)	O
.	O
</s>
<s>
Though	O
a	O
contest	O
was	O
planned	O
for	O
2000	O
,	O
the	O
interest	O
in	O
the	O
N64	B-Operating_System
was	O
already	O
fading	O
,	O
and	O
so	O
did	O
the	O
event	O
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
unit	O
was	O
the	O
first	O
commercially	O
available	O
backup	B-Device
device	I-Device
for	O
the	O
Nintendo	B-Operating_System
64	I-Operating_System
unit	O
.	O
</s>
<s>
Original	O
Doctor	B-Device
V64	I-Device
units	O
sold	O
by	O
Bung	O
did	O
not	O
allow	O
the	O
playing	O
of	O
backups	O
.	O
</s>
<s>
This	O
usually	O
required	O
a	O
user	O
to	O
download	O
and	O
install	O
a	O
modified	O
Doctor	B-Device
V64	I-Device
BIOS	B-Operating_System
.	O
</s>
<s>
During	O
the	O
N64	B-Operating_System
's	O
lifetime	O
,	O
Nintendo	O
revised	O
the	O
N64	B-Operating_System
's	O
model	O
,	O
making	O
the	O
serial	O
port	O
area	O
smaller	O
.	O
</s>
<s>
This	O
slight	O
change	O
in	O
the	O
N64	B-Operating_System
's	O
plastic	O
casing	O
made	O
the	O
connection	O
to	O
the	O
Doctor	B-Device
V64	I-Device
difficult	O
to	O
achieve	O
without	O
user	O
modification	O
.	O
</s>
<s>
This	O
revision	O
may	O
have	O
been	O
a	O
direct	O
reaction	O
from	O
Nintendo	O
to	O
discourage	O
the	O
use	O
of	O
V64	O
devices	O
,	O
and	O
may	O
also	O
explain	O
why	O
Bung	O
decided	O
to	O
discontinue	O
the	O
use	O
of	O
this	O
port	O
in	O
the	O
later	O
Doctor	B-Device
V64	I-Device
Jr.	O
models	O
.	O
</s>
<s>
Nintendo	O
made	O
many	O
legal	O
efforts	O
worldwide	O
in	O
order	O
to	O
stop	O
the	O
sale	O
of	O
Doctor	B-Device
V64	I-Device
units	O
.	O
</s>
<s>
Eventually	O
,	O
Nintendo	O
managed	O
to	O
have	O
the	O
courts	O
prohibit	O
the	O
sale	O
of	O
Doctor	B-Device
V64	I-Device
units	O
in	O
the	O
United	O
States	O
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
implemented	O
text-based	O
menu-driven	O
screens	O
.	O
</s>
<s>
Though	O
the	O
menu	O
was	O
mainly	O
designed	O
for	O
game	O
developers	O
,	O
it	O
is	O
possible	O
to	O
back	O
up	O
cartridges	O
with	O
it	O
(	O
through	O
the	O
use	O
of	O
an	O
unofficial	O
V64	O
BIOS	B-Operating_System
)	O
.	O
</s>
<s>
Some	O
of	O
the	O
menu	O
items	O
related	O
to	O
game	O
backups	O
were	O
removed	O
from	O
the	O
V64	O
's	O
BIOS	B-Operating_System
near	O
the	O
end	O
of	O
its	O
life	O
due	O
to	O
pressure	O
from	O
Nintendo	O
.	O
</s>
<s>
These	O
items	O
are	O
only	O
available	O
by	O
obtaining	O
a	O
patched	O
V64	O
BIOS	B-Operating_System
.	O
</s>
<s>
Backup	O
Card	O
Auto	O
→	O
PC	O
Same	O
as	O
the	O
previous	O
option	O
,	O
but	O
would	O
transfer	O
the	O
data	O
to	O
a	O
PC	O
through	O
the	O
V64	O
's	O
parallel	B-Device
port	I-Device
.	O
</s>
<s>
Upload	O
DRAM	O
Data	O
→	O
PC	O
Used	O
in	O
conjunction	O
with	O
the	O
option	O
"	O
Backup	O
Card	O
Auto	O
→	O
DRAM	O
"	O
,	O
this	O
option	O
would	O
transfer	O
the	O
contents	O
of	O
Doctor	B-Device
V64	I-Device
's	O
RAM	O
to	O
a	O
PC	O
through	O
the	O
use	O
of	O
V64	O
's	O
parallel	B-Device
port	I-Device
.	O
</s>
<s>
Upload	O
V64	O
BIOS	B-Operating_System
to	O
PC	O
Another	O
advanced	O
option	O
for	O
DV64	O
developers	O
.	O
</s>
<s>
It	O
would	O
transfer	O
the	O
Doctor	B-Device
V64	I-Device
's	O
own	O
program	O
code	O
to	O
the	O
PC	O
through	O
a	O
parallel	O
connection	O
.	O
</s>
<s>
Later	O
bios	B-Operating_System
revisions	O
would	O
do	O
this	O
automatically	O
,	O
deprecating	O
this	O
option	O
.	O
</s>
<s>
Most	O
early	O
V64	O
models	O
shipped	O
with	O
a	O
standard	O
IDE	B-Protocol
8X	O
CD-ROM	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
replace	O
the	O
unit	O
with	O
a	O
faster	O
IDE	B-Protocol
CD-ROM	O
unit	O
(	O
such	O
as	O
the	O
52X	O
model	O
in	O
the	O
image	O
on	O
this	O
page	O
)	O
.	O
</s>
<s>
Many	O
Doctor	B-Device
V64s	I-Device
shipped	O
internationally	O
were	O
ordered	O
without	O
an	O
installed	O
CD-ROM	O
drive	O
,	O
to	O
save	O
on	O
shipping	O
costs	O
associated	O
with	O
weight	O
,	O
to	O
avoid	O
import	O
duty	O
on	O
the	O
drive	O
,	O
and	O
to	O
allow	O
users	O
to	O
customize	O
the	O
units	O
in	O
response	O
to	O
the	O
ever-increasing	O
speeds	O
of	O
drives	O
available	O
.	O
</s>
<s>
The	O
variance	O
in	O
the	O
power	O
draw	O
of	O
different	O
manufacturers	O
drives	O
at	B-Device
different	O
speeds	O
caused	O
issues	O
with	O
disc	O
spin-ups	O
exceeding	O
the	O
wattage	O
rating	O
of	O
the	O
included	O
Bung	O
PSU	O
.	O
</s>
<s>
Supported	O
media	O
has	O
to	O
be	O
recorded	O
in	O
Mode	O
1	O
,	O
ISO	B-Application
9660	I-Application
format	O
.	O
</s>
<s>
Doctor	B-Device
V64s	I-Device
only	O
support	O
the	O
8.3	O
DOS	O
naming	O
convention	O
.	O
</s>
<s>
The	O
Doctor	B-Device
V64	I-Device
uses	O
a	O
4	O
Pin	O
MiniDIN	O
jack	O
(	O
as	O
used	O
for	O
S-Video	O
)	O
for	O
connecting	O
the	O
power	O
supply	O
cord	O
.	O
</s>
<s>
Power	O
supplies	O
included	O
with	O
Doctor	B-Device
V64s	I-Device
were	O
very	O
unreliable	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
modify	O
an	O
AT	B-Device
PC	O
power	O
supply	O
for	O
V64	O
use	O
.	O
</s>
<s>
The	O
ROM	O
extensions	O
"	O
.v64	O
"	O
and	O
"	O
.z64	O
"	O
started	O
out	O
as	O
the	O
preferred	O
naming	O
conventions	O
by	O
Doctor	B-Device
V64	I-Device
and	O
Z64	B-Application
users	O
,	O
respectively	O
.	O
</s>
<s>
It	O
would	O
also	O
imply	O
the	O
file	O
's	O
"	O
endianness	O
"	O
as	O
those	O
units	O
employed	O
little	O
endian	O
(	O
V64	O
)	O
and	O
big	O
endian	O
(	O
Z64	B-Application
)	O
byte	O
alignment	O
.	O
</s>
<s>
"	O
.n64	O
"	O
was	O
used	O
as	O
well	O
but	O
not	O
as	O
much	O
(	O
it	O
became	O
more	O
popular	O
as	O
N64	B-Operating_System
emulators	O
began	O
to	O
appear	O
)	O
.	O
</s>
<s>
The	O
terms	O
"	O
.v64	O
"	O
and	O
"	O
.z64	O
"	O
are	O
still	O
widely	O
used	O
today	O
by	O
the	O
emulation	O
community	O
.	O
</s>
<s>
Acclaim	O
Entertainment	O
subsidiary	O
Iguana	O
Entertainment	O
used	O
Doctor	B-Device
V64	I-Device
units	O
as	O
their	O
development	O
hardware	O
of	O
choice	O
during	O
the	O
N64	B-Operating_System
era	O
.	O
</s>
<s>
They	O
were	O
best	O
known	O
for	O
developing	O
the	O
Turok	B-Application
,	O
NBA	B-Application
Jam	I-Application
,	O
NFL	B-Device
Quarterback	I-Device
Club	I-Device
,	O
and	O
South	B-Application
Park	I-Application
video	O
games	O
.	O
</s>
